Hi, I'm new to python. I need to generate a new raster C from two rasters A and B by first multiplying a constant value with all elements of raster A and then adding A and B. I need to generate raster C for multiple years so I have it looping over the years I need. However, line 41 below is not giving the correct value after multiplication except on the first iteration through the loop at line 27. Can anyone explain why that might be? Why does this code only work on the first iteration? EDIT: the code also works without using the Decimal module but still only gives the correct raster on the first iteration import arcpy import numpy import decimal #inRas = arcpy.Raster("C:/VegModel/CCSSRawData.gdb/vegnorm") #lowerLeft = arcpy.Point(inRas.extent.XMin,inRas.extent.YMin) #cellSize = inRas.meanCellWidth inRasPETcgcm = arcpy . Raster ( "C:/VegModel/CCSSRawData.gdb/petCgcmRS100Clip" ) inRasPETnorm = arcpy . Raster ( "C:/VegModel/CCSSRawData.gdb/petNormRS100Clip" ) lowerLeft = arcpy . Point ( inRasPETnorm . extent . XMin , inRasPETnorm . extent . YMin ) cellSize = inRasPETnorm . meanCellWidth inArrayPETcgcm = arcpy . RasterToNumPyArray ( inRasPETcgcm ) #inArrayPETcgcm = inArrayPETcgcm * 30 inArrayPETnorm = arcpy . RasterToNumPyArray ( inRasPETnorm ) rasHeight , rasWidth = inArrayPETnorm . shape #outArrayPET = inArrayPETnorm + inArrayPETcgcm outArrayPET = inArrayPETnorm decimal . getcontext ( ) . prec = 20 for x in range ( 0 , 3 ) : for i in range ( 0 , 2 ) : for j in range ( 0 , 2 ) : value1 = str ( inArrayPETcgcm [ i , j ] ) value2 = str ( inArrayPETnorm [ i , j ] ) loopValue = str ( x ) #print "value1 is: " #print value1 #print "value2 is: " #print value2 value1 = decimal . Decimal ( value1 ) * decimal . Decimal ( loopValue ) #print "value1 after multiplication is: " #print value1 value3 = value1 + decimal . Decimal ( value2 ) #print "value3 is: " #print value3 outArrayPET [ i , j ] = value3 newRasPET = arcpy . NumPyArrayToRaster ( outArrayPET , lowerLeft , cellSize ) newRasPET . save ( "C:/VegModel/Revise.gdb/pet100ReviseYear%dB" % x )

Thank you for all the time you have put in to help me, Dan. Thank you! When I did this: arrayA = arrayA * x arrayC = arrayB + arrayA where x multiplies the entire arrayA instead of going through cell by cell I could not get x to loop beyond 2. So I wanted to use a smaller section of the original array to post as a sample to test. But I didn't understand that trying to get a smaller section was still going through an array cell by cell. I don't want to go through an array cell by cell. But nothing else was working. Why does the code only work when going cell by cell.

well... there have been 26 views to this thread... no one else has had any comments... and I still can't get a straight answer as to what you are doing or why you keep insisting on processing on a cell by cell basis... In this situation, it is time to bail and let the other viewers leap in with their interpretation of what is being done.. So in summary... you dont work with numpy arrays on a cell-by-cell basis... you use vectorized operations at worse or full array and/or scalar operations as normal. Once you or someone can clarify this situation I will defer to the viewing gallery to leap in with their insights

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Looping through rasters only give correct result on first iteration

XinXia1

Hi,

I'm new to python. I need to generate a new raster C from two rasters A and B by first multiplying a constant value with all elements of raster A and then adding A and B. I need to generate raster C for multiple years so I have it looping over the years I need. However, line 41 below is not giving the correct value after multiplication except on the first iteration through the loop at line 27. Can anyone explain why that might be? Why does this code only work on the first iteration?

EDIT: the code also works without using the Decimal module but still only gives the correct raster on the first iteration

<SPAN class="keyword token">import</SPAN> arcpy
<SPAN class="keyword token">import</SPAN> numpy
<SPAN class="keyword token">import</SPAN> decimal

<SPAN class="comment token">#inRas = arcpy.Raster("C:/VegModel/CCSSRawData.gdb/vegnorm")</SPAN>
<SPAN class="comment token">#lowerLeft = arcpy.Point(inRas.extent.XMin,inRas.extent.YMin)</SPAN>
<SPAN class="comment token">#cellSize = inRas.meanCellWidth</SPAN>

inRasPETcgcm <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>Raster<SPAN class="punctuation token">(</SPAN><SPAN class="string token">"C:/VegModel/CCSSRawData.gdb/petCgcmRS100Clip"</SPAN><SPAN class="punctuation token">)</SPAN>
inRasPETnorm <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>Raster<SPAN class="punctuation token">(</SPAN><SPAN class="string token">"C:/VegModel/CCSSRawData.gdb/petNormRS100Clip"</SPAN><SPAN class="punctuation token">)</SPAN>

lowerLeft <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>Point<SPAN class="punctuation token">(</SPAN>inRasPETnorm<SPAN class="punctuation token">.</SPAN>extent<SPAN class="punctuation token">.</SPAN>XMin<SPAN class="punctuation token">,</SPAN>inRasPETnorm<SPAN class="punctuation token">.</SPAN>extent<SPAN class="punctuation token">.</SPAN>YMin<SPAN class="punctuation token">)</SPAN>
cellSize <SPAN class="operator token">=</SPAN> inRasPETnorm<SPAN class="punctuation token">.</SPAN>meanCellWidth

inArrayPETcgcm <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>RasterToNumPyArray<SPAN class="punctuation token">(</SPAN>inRasPETcgcm<SPAN class="punctuation token">)</SPAN>
<SPAN class="comment token">#inArrayPETcgcm = inArrayPETcgcm * 30</SPAN>
inArrayPETnorm <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>RasterToNumPyArray<SPAN class="punctuation token">(</SPAN>inRasPETnorm<SPAN class="punctuation token">)</SPAN>

rasHeight<SPAN class="punctuation token">,</SPAN> rasWidth <SPAN class="operator token">=</SPAN> inArrayPETnorm<SPAN class="punctuation token">.</SPAN>shape

<SPAN class="comment token">#outArrayPET = inArrayPETnorm + inArrayPETcgcm</SPAN>

outArrayPET <SPAN class="operator token">=</SPAN> inArrayPETnorm

decimal<SPAN class="punctuation token">.</SPAN>getcontext<SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">.</SPAN>prec <SPAN class="operator token">=</SPAN> <SPAN class="number token">20</SPAN>

<SPAN class="keyword token">for</SPAN> x <SPAN class="keyword token">in</SPAN> range <SPAN class="punctuation token">(</SPAN><SPAN class="number token">0</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">3</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">:</SPAN>
&nbsp;&nbsp;&nbsp; <SPAN class="keyword token">for</SPAN> i <SPAN class="keyword token">in</SPAN> range<SPAN class="punctuation token">(</SPAN><SPAN class="number token">0</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">2</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">:</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="keyword token">for</SPAN> j <SPAN class="keyword token">in</SPAN> range<SPAN class="punctuation token">(</SPAN><SPAN class="number token">0</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">2</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">:</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; value1 <SPAN class="operator token">=</SPAN> str<SPAN class="punctuation token">(</SPAN>inArrayPETcgcm<SPAN class="punctuation token">[</SPAN>i<SPAN class="punctuation token">,</SPAN> j<SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">)</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; value2 <SPAN class="operator token">=</SPAN> str<SPAN class="punctuation token">(</SPAN>inArrayPETnorm<SPAN class="punctuation token">[</SPAN>i<SPAN class="punctuation token">,</SPAN> j<SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">)</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; loopValue <SPAN class="operator token">=</SPAN> str<SPAN class="punctuation token">(</SPAN>x<SPAN class="punctuation token">)</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="comment token">#print "value1 is: "</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="comment token">#print value1</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="comment token">#print "value2 is: "</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="comment token">#print value2</SPAN>

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; value1 <SPAN class="operator token">=</SPAN> decimal<SPAN class="punctuation token">.</SPAN>Decimal<SPAN class="punctuation token">(</SPAN>value1<SPAN class="punctuation token">)</SPAN> <SPAN class="operator token">*</SPAN> decimal<SPAN class="punctuation token">.</SPAN>Decimal<SPAN class="punctuation token">(</SPAN>loopValue<SPAN class="punctuation token">)</SPAN>

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="comment token">#print "value1 after multiplication is: "</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="comment token">#print value1</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; value3 <SPAN class="operator token">=</SPAN> value1 <SPAN class="operator token">+</SPAN> decimal<SPAN class="punctuation token">.</SPAN>Decimal<SPAN class="punctuation token">(</SPAN>value2<SPAN class="punctuation token">)</SPAN>

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="comment token">#print "value3 is: "</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="comment token">#print value3</SPAN>

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; outArrayPET<SPAN class="punctuation token">[</SPAN>i<SPAN class="punctuation token">,</SPAN> j<SPAN class="punctuation token">]</SPAN> <SPAN class="operator token">=</SPAN> value3
&nbsp;&nbsp;&nbsp; 
&nbsp;&nbsp;&nbsp; newRasPET <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>NumPyArrayToRaster<SPAN class="punctuation token">(</SPAN>outArrayPET<SPAN class="punctuation token">,</SPAN> lowerLeft<SPAN class="punctuation token">,</SPAN> cellSize<SPAN class="punctuation token">)</SPAN>
&nbsp;&nbsp;&nbsp; newRasPET<SPAN class="punctuation token">.</SPAN>save<SPAN class="punctuation token">(</SPAN><SPAN class="string token">"C:/VegModel/Revise.gdb/pet100ReviseYear%dB"</SPAN> <SPAN class="operator token">%</SPAN>x<SPAN class="punctuation token">)</SPAN>

‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍<SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

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DanPatterson_Retired

this is from a related thread... here is how to work with rasters and conditional statement

https://community.esri.com/thread/188417-how-to-make-raster-conditionals-more-efficient

DanPatterson_Retired

<SPAN class="keyword token">import</SPAN> numpy <SPAN class="keyword token">as</SPAN> np
a <SPAN class="operator token">=</SPAN> np<SPAN class="punctuation token">.</SPAN>arange<SPAN class="punctuation token">(</SPAN><SPAN class="number token">4</SPAN><SPAN class="operator token">*</SPAN><SPAN class="number token">6</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">.</SPAN>reshape<SPAN class="punctuation token">(</SPAN><SPAN class="number token">4</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">6</SPAN><SPAN class="punctuation token">)</SPAN>
b <SPAN class="operator token">=</SPAN> np<SPAN class="punctuation token">.</SPAN>zeros<SPAN class="punctuation token">(</SPAN><SPAN class="number token">4</SPAN><SPAN class="operator token">*</SPAN><SPAN class="number token">6</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">.</SPAN>reshape<SPAN class="punctuation token">(</SPAN><SPAN class="number token">4</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">6</SPAN><SPAN class="punctuation token">)</SPAN>

<SPAN class="keyword token">for</SPAN> i <SPAN class="keyword token">in</SPAN> range <SPAN class="punctuation token">(</SPAN><SPAN class="number token">5</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">:</SPAN>
&nbsp;&nbsp;&nbsp; <SPAN class="keyword token">for</SPAN> j <SPAN class="keyword token">in</SPAN> range <SPAN class="punctuation token">(</SPAN><SPAN class="number token">7</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">:</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; v1 <SPAN class="operator token">=</SPAN> a<SPAN class="punctuation token">[</SPAN>i<SPAN class="punctuation token">:</SPAN>j<SPAN class="punctuation token">]</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; v2 <SPAN class="operator token">=</SPAN> a<SPAN class="punctuation token">[</SPAN>i<SPAN class="punctuation token">:</SPAN>j<SPAN class="punctuation token">]</SPAN> <SPAN class="operator token">+</SPAN> <SPAN class="number token">2</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; b<SPAN class="punctuation token">[</SPAN>i<SPAN class="punctuation token">:</SPAN>j<SPAN class="punctuation token">]</SPAN> <SPAN class="operator token">=</SPAN> v1 <SPAN class="operator token">+</SPAN> v2

<SPAN class="keyword token">print</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="string token">"array a \n{}\narray b \n{}"</SPAN><SPAN class="punctuation token">.</SPAN>format<SPAN class="punctuation token">(</SPAN>a<SPAN class="punctuation token">,</SPAN> b<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

you seem to be mixing up commas and colons...

See this generic example... ie. it is a lesson, not a direct solution

array a 
<SPAN class="punctuation token">[</SPAN><SPAN class="punctuation token">[</SPAN> <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">1</SPAN>&nbsp; <SPAN class="number token">2</SPAN>&nbsp; <SPAN class="number token">3</SPAN>&nbsp; <SPAN class="number token">4</SPAN>&nbsp; <SPAN class="number token">5</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN> <SPAN class="number token">6</SPAN>&nbsp; <SPAN class="number token">7</SPAN>&nbsp; <SPAN class="number token">8</SPAN>&nbsp; <SPAN class="number token">9</SPAN> <SPAN class="number token">10</SPAN> <SPAN class="number token">11</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN><SPAN class="number token">12</SPAN> <SPAN class="number token">13</SPAN> <SPAN class="number token">14</SPAN> <SPAN class="number token">15</SPAN> <SPAN class="number token">16</SPAN> <SPAN class="number token">17</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN><SPAN class="number token">18</SPAN> <SPAN class="number token">19</SPAN> <SPAN class="number token">20</SPAN> <SPAN class="number token">21</SPAN> <SPAN class="number token">22</SPAN> <SPAN class="number token">23</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">]</SPAN>
array b 
<SPAN class="punctuation token">[</SPAN><SPAN class="punctuation token">[</SPAN> <SPAN class="number token">2.000</SPAN>&nbsp; <SPAN class="number token">4.000</SPAN>&nbsp; <SPAN class="number token">6.000</SPAN>&nbsp; <SPAN class="number token">8.000</SPAN>&nbsp; <SPAN class="number token">10.000</SPAN>&nbsp; <SPAN class="number token">12.000</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN> <SPAN class="number token">14.000</SPAN>&nbsp; <SPAN class="number token">16.000</SPAN>&nbsp; <SPAN class="number token">18.000</SPAN>&nbsp; <SPAN class="number token">20.000</SPAN>&nbsp; <SPAN class="number token">22.000</SPAN>&nbsp; <SPAN class="number token">24.000</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN> <SPAN class="number token">26.000</SPAN>&nbsp; <SPAN class="number token">28.000</SPAN>&nbsp; <SPAN class="number token">30.000</SPAN>&nbsp; <SPAN class="number token">32.000</SPAN>&nbsp; <SPAN class="number token">34.000</SPAN>&nbsp; <SPAN class="number token">36.000</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN> <SPAN class="number token">38.000</SPAN>&nbsp; <SPAN class="number token">40.000</SPAN>&nbsp; <SPAN class="number token">42.000</SPAN>&nbsp; <SPAN class="number token">44.000</SPAN>&nbsp; <SPAN class="number token">46.000</SPAN>&nbsp; <SPAN class="number token">48.000</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

If you want array b to be integers, b = np.zeros(3*4, dtype='int').reshape(3,4)

XinXia1

Hi Dan

I'm not good with python yet. I was trying this code to post a sample, but it gave me this error. I think it's something simple that I'm not understanding with python.

Error:

Traceback (most recent call last):
&nbsp; File "C:\PyTest\petCode.py", line 23, in <module>
&nbsp;&nbsp;&nbsp; a<I><J> = v1
IndexError: index 6 is out of bounds for axis 0 with size 6<SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN></J></I>

Code:

<SPAN class="keyword token">import</SPAN> arcpy
<SPAN class="keyword token">import</SPAN> numpy

inRasCgcm <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>Raster<SPAN class="punctuation token">(</SPAN><SPAN class="string token">"C:/PyTest/testResult.gdb/petCRsClip"</SPAN><SPAN class="punctuation token">)</SPAN>
inRasNorm <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>Raster<SPAN class="punctuation token">(</SPAN><SPAN class="string token">"C:/PyTest/testResult.gdb/petNRsClip"</SPAN><SPAN class="punctuation token">)</SPAN>

lowerLeft <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>Point<SPAN class="punctuation token">(</SPAN>inRasNorm<SPAN class="punctuation token">.</SPAN>extent<SPAN class="punctuation token">.</SPAN>XMin<SPAN class="punctuation token">,</SPAN>inRasNorm<SPAN class="punctuation token">.</SPAN>extent<SPAN class="punctuation token">.</SPAN>YMin<SPAN class="punctuation token">)</SPAN>
cellSize <SPAN class="operator token">=</SPAN> inRasNorm<SPAN class="punctuation token">.</SPAN>meanCellWidth

inArrayCgcm <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>RasterToNumPyArray<SPAN class="punctuation token">(</SPAN>inRasCgcm<SPAN class="punctuation token">)</SPAN>
inArrayNorm <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>RasterToNumPyArray<SPAN class="punctuation token">(</SPAN>inRasNorm<SPAN class="punctuation token">)</SPAN>

<SPAN class="comment token">#outArrayPE = numpy.zeros_like(inArrayNorm)</SPAN>

a <SPAN class="operator token">=</SPAN> numpy<SPAN class="punctuation token">.</SPAN>zeros<SPAN class="punctuation token">(</SPAN><SPAN class="number token">4</SPAN><SPAN class="operator token">*</SPAN><SPAN class="number token">6</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">.</SPAN>reshape<SPAN class="punctuation token">(</SPAN><SPAN class="number token">4</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">6</SPAN><SPAN class="punctuation token">)</SPAN>
b <SPAN class="operator token">=</SPAN> numpy<SPAN class="punctuation token">.</SPAN>zeros<SPAN class="punctuation token">(</SPAN><SPAN class="number token">4</SPAN><SPAN class="operator token">*</SPAN><SPAN class="number token">6</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">.</SPAN>reshape<SPAN class="punctuation token">(</SPAN><SPAN class="number token">4</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">6</SPAN><SPAN class="punctuation token">)</SPAN>

<SPAN class="keyword token">for</SPAN> i <SPAN class="keyword token">in</SPAN> range <SPAN class="punctuation token">(</SPAN><SPAN class="number token">5</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">:</SPAN>
&nbsp;&nbsp;&nbsp; <SPAN class="keyword token">for</SPAN> j <SPAN class="keyword token">in</SPAN> range <SPAN class="punctuation token">(</SPAN><SPAN class="number token">7</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">:</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; v1 <SPAN class="operator token">=</SPAN> inArrayCgcm<SPAN class="punctuation token">[</SPAN>i<SPAN class="punctuation token">,</SPAN> j<SPAN class="punctuation token">]</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; v2 <SPAN class="operator token">=</SPAN> inArrayNorm<SPAN class="punctuation token">[</SPAN>i<SPAN class="punctuation token">,</SPAN> j<SPAN class="punctuation token">]</SPAN>

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; a<SPAN class="punctuation token">[</SPAN>i<SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">[</SPAN>j<SPAN class="punctuation token">]</SPAN> <SPAN class="operator token">=</SPAN> v1
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; b<SPAN class="punctuation token">[</SPAN>i<SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">[</SPAN>j<SPAN class="punctuation token">]</SPAN> <SPAN class="operator token">=</SPAN> v2

<SPAN class="keyword token">print</SPAN> <SPAN class="string token">"array a \n"</SPAN>
<SPAN class="keyword token">print</SPAN> a

<SPAN class="keyword token">print</SPAN> <SPAN class="string token">"array b \n"</SPAN>
<SPAN class="keyword token">print</SPAN> b<SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

DanPatterson_Retired

if it makes through 2, then something is wrong with the data... as suggested, slice it to a smaller area, post a sample, or just use the subset for testing

XinXia1

Hi Dan,

Thank you so much for all your help. I changed to shorter file names, but I am getting the same error.

Error:

Traceback (most recent call last):
&nbsp; File "C:\PyTest\petCode.py", line 19, in <module>
&nbsp;&nbsp;&nbsp; newRasPET = arcpy.NumPyArrayToRaster(outArrayPE, lowerLeft, cellSize)
&nbsp; File "C:\Program Files (x86)\ArcGIS\Desktop10.3\ArcPy\arcpy\__init__.py", line 2292, in NumPyArrayToRaster
&nbsp;&nbsp;&nbsp; return _NumPyArrayToRaster(*args, **kwargs)
TypeError: Cannot create raster for numpy array.‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍<SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

The code now makes it 2 iterations with correct raster values thank you for showing me the zeros_like() to properly initialize an array.

Latest code:

<SPAN class="keyword token">import</SPAN> arcpy
<SPAN class="keyword token">import</SPAN> numpy

inRasCgcm <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>Raster<SPAN class="punctuation token">(</SPAN><SPAN class="string token">"C:/PyTest/testResult.gdb/petCRsClip"</SPAN><SPAN class="punctuation token">)</SPAN>
inRasNorm <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>Raster<SPAN class="punctuation token">(</SPAN><SPAN class="string token">"C:/PyTest/testResult.gdb/petNRsClip"</SPAN><SPAN class="punctuation token">)</SPAN>

lowerLeft <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>Point<SPAN class="punctuation token">(</SPAN>inRasNorm<SPAN class="punctuation token">.</SPAN>extent<SPAN class="punctuation token">.</SPAN>XMin<SPAN class="punctuation token">,</SPAN>inRasNorm<SPAN class="punctuation token">.</SPAN>extent<SPAN class="punctuation token">.</SPAN>YMin<SPAN class="punctuation token">)</SPAN>
cellSize <SPAN class="operator token">=</SPAN> inRasNorm<SPAN class="punctuation token">.</SPAN>meanCellWidth

inArrayCgcm <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>RasterToNumPyArray<SPAN class="punctuation token">(</SPAN>inRasCgcm<SPAN class="punctuation token">)</SPAN>
inArrayNorm <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>RasterToNumPyArray<SPAN class="punctuation token">(</SPAN>inRasNorm<SPAN class="punctuation token">)</SPAN>

outArrayPE <SPAN class="operator token">=</SPAN> numpy<SPAN class="punctuation token">.</SPAN>zeros_like<SPAN class="punctuation token">(</SPAN>inArrayNorm<SPAN class="punctuation token">)</SPAN>

<SPAN class="keyword token">for</SPAN> x <SPAN class="keyword token">in</SPAN> range <SPAN class="punctuation token">(</SPAN><SPAN class="number token">1</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">4</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">:</SPAN>
&nbsp;&nbsp;&nbsp; inArrayCgcm <SPAN class="operator token">=</SPAN> inArrayCgcm <SPAN class="operator token">*</SPAN> x
&nbsp;&nbsp;&nbsp; outArrayPE <SPAN class="operator token">=</SPAN> inArrayNorm <SPAN class="operator token">+</SPAN> inArrayCgcm

&nbsp;&nbsp;&nbsp; newRasPET <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>NumPyArrayToRaster<SPAN class="punctuation token">(</SPAN>outArrayPE<SPAN class="punctuation token">,</SPAN> lowerLeft<SPAN class="punctuation token">,</SPAN> cellSize<SPAN class="punctuation token">)</SPAN>
&nbsp;&nbsp;&nbsp; newRasPET<SPAN class="punctuation token">.</SPAN>save<SPAN class="punctuation token">(</SPAN><SPAN class="string token">"C:/PyTest/testResult.gdb/petR{}Year"</SPAN><SPAN class="punctuation token">.</SPAN>format<SPAN class="punctuation token">(</SPAN>x<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">)</SPAN>‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍<SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

The structure of my array and saving location should be okay if I can make it to 2 iterations correctly shouldn't it?

XinXia1

Hi Dan,

Thank you for all your help. I see this code as NOT go through the array cell by cell. It is doing exactly what you are showing above. I AM multiplying the entire array inArrayPETcgcm by the constant x. If inArrayPETcgcm was array A like you have above. Then array A would have:

array dimensions (ndim) = 2

array shape (shape) = (5400, 6318)

Loop x just goes from 1 to 50 as the constants that get multiplied to the entire array.

<SPAN class="keyword token">import</SPAN> arcpy
<SPAN class="keyword token">import</SPAN> numpy

inRasPETcgcm <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>Raster<SPAN class="punctuation token">(</SPAN><SPAN class="string token">"C:/VegModel/CCSSRawData.gdb/petCgcmRS100Clip"</SPAN><SPAN class="punctuation token">)</SPAN>
inRasPETnorm <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>Raster<SPAN class="punctuation token">(</SPAN><SPAN class="string token">"C:/VegModel/CCSSRawData.gdb/petNormRS100Clip"</SPAN><SPAN class="punctuation token">)</SPAN>

lowerLeft <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>Point<SPAN class="punctuation token">(</SPAN>inRasPETnorm<SPAN class="punctuation token">.</SPAN>extent<SPAN class="punctuation token">.</SPAN>XMin<SPAN class="punctuation token">,</SPAN>inRasPETnorm<SPAN class="punctuation token">.</SPAN>extent<SPAN class="punctuation token">.</SPAN>YMin<SPAN class="punctuation token">)</SPAN>
cellSize <SPAN class="operator token">=</SPAN> inRasPETnorm<SPAN class="punctuation token">.</SPAN>meanCellWidth

inArrayPETcgcm <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>RasterToNumPyArray<SPAN class="punctuation token">(</SPAN>inRasPETcgcm<SPAN class="punctuation token">)</SPAN>

inArrayPETnorm <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>RasterToNumPyArray<SPAN class="punctuation token">(</SPAN>inRasPETnorm<SPAN class="punctuation token">)</SPAN>


<SPAN class="keyword token">for</SPAN> x <SPAN class="keyword token">in</SPAN> range <SPAN class="punctuation token">(</SPAN><SPAN class="number token">1</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">51</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">:</SPAN>
&nbsp;&nbsp;&nbsp; inArrayPETcgcm <SPAN class="operator token">=</SPAN> inArrayPETcgcm <SPAN class="operator token">*</SPAN> x

&nbsp;&nbsp;&nbsp; outArrayPET <SPAN class="operator token">=</SPAN> inArrayPETnorm <SPAN class="operator token">+</SPAN> inArrayPETcgcm
&nbsp;&nbsp;&nbsp; 
&nbsp;&nbsp;&nbsp; newRasPET <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>NumPyArrayToRaster<SPAN class="punctuation token">(</SPAN>outArrayPET<SPAN class="punctuation token">,</SPAN> lowerLeft<SPAN class="punctuation token">,</SPAN> cellSize<SPAN class="punctuation token">)</SPAN>
&nbsp;&nbsp;&nbsp; newRasPET<SPAN class="punctuation token">.</SPAN>save<SPAN class="punctuation token">(</SPAN><SPAN class="string token">"C:/VegModel/Revise.gdb/pet100ReviseYear%dB"</SPAN> <SPAN class="operator token">%</SPAN>x<SPAN class="punctuation token">)</SPAN>‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍<SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

How are you reading this code as going through the array cell by cell? I'm honestly so confused? If I am wrong please let me know.

DanPatterson_Retired

You don't go through arrays cell by cell.. If you want to 'do something' to an array, you apply the function or whatever all at once. ... last crack..

>>> a = np.arange(3*4).reshape(3,4)
>>> a
array([[ 0, 1, 2, 3],
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; [ 4, 5, 6, 7],
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; [ 8, 9, 10, 11]])
>>> a*3
array([[ 0, 3, 6, 9],
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; [12, 15, 18, 21],
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; [24, 27, 30, 33]])
>>> (a * 3)/a.max()
array([[ 0.000, 0.273, 0.545, 0.818],
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; [ 1.091, 1.364, 1.636, 1.909],
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; [ 2.182, 2.455, 2.727, 3.000]])‍‍‍‍‍‍‍‍‍‍‍‍‍
<SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

XinXia1

Hi Dan,

I know going through an array cell by cell is very inefficient. So the first code I tried did not got through my array cell by cell. The first code I tried looked like this:

<SPAN class="keyword token">import</SPAN> arcpy
<SPAN class="keyword token">import</SPAN> numpy

inRasPETcgcm <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>Raster<SPAN class="punctuation token">(</SPAN><SPAN class="string token">"C:/VegModel/CCSSRawData.gdb/petCgcmRS100Clip"</SPAN><SPAN class="punctuation token">)</SPAN>
inRasPETnorm <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>Raster<SPAN class="punctuation token">(</SPAN><SPAN class="string token">"C:/VegModel/CCSSRawData.gdb/petNormRS100Clip"</SPAN><SPAN class="punctuation token">)</SPAN>

lowerLeft <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>Point<SPAN class="punctuation token">(</SPAN>inRasPETnorm<SPAN class="punctuation token">.</SPAN>extent<SPAN class="punctuation token">.</SPAN>XMin<SPAN class="punctuation token">,</SPAN>inRasPETnorm<SPAN class="punctuation token">.</SPAN>extent<SPAN class="punctuation token">.</SPAN>YMin<SPAN class="punctuation token">)</SPAN>
cellSize <SPAN class="operator token">=</SPAN> inRasPETnorm<SPAN class="punctuation token">.</SPAN>meanCellWidth

inArrayPETcgcm <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>RasterToNumPyArray<SPAN class="punctuation token">(</SPAN>inRasPETcgcm<SPAN class="punctuation token">)</SPAN>

inArrayPETnorm <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>RasterToNumPyArray<SPAN class="punctuation token">(</SPAN>inRasPETnorm<SPAN class="punctuation token">)</SPAN>


<SPAN class="keyword token">for</SPAN> x <SPAN class="keyword token">in</SPAN> range <SPAN class="punctuation token">(</SPAN><SPAN class="number token">1</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">51</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">:</SPAN>
&nbsp;&nbsp;&nbsp; inArrayPETcgcm <SPAN class="operator token">=</SPAN> inArrayPETcgcm <SPAN class="operator token">*</SPAN> x

&nbsp;&nbsp;&nbsp; outArrayPET <SPAN class="operator token">=</SPAN> inArrayPETnorm <SPAN class="operator token">+</SPAN> inArrayPETcgcm
&nbsp;&nbsp;&nbsp; 
&nbsp;&nbsp;&nbsp; newRasPET <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>NumPyArrayToRaster<SPAN class="punctuation token">(</SPAN>outArrayPET<SPAN class="punctuation token">,</SPAN> lowerLeft<SPAN class="punctuation token">,</SPAN> cellSize<SPAN class="punctuation token">)</SPAN>
&nbsp;&nbsp;&nbsp; newRasPET<SPAN class="punctuation token">.</SPAN>save<SPAN class="punctuation token">(</SPAN><SPAN class="string token">"C:/VegModel/Revise.gdb/pet100ReviseYear%dB"</SPAN> <SPAN class="operator token">%</SPAN>x<SPAN class="punctuation token">)</SPAN><SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

This code would also give me the incorrect values after the first iteration, and it would crash after only 2 iterations giving me an error like this:

Traceback (most recent call last):
&nbsp; File "C:\VegModel\PETyearlyChange.py", line 20, in <module>
&nbsp;&nbsp;&nbsp; newRasPET = arcpy.NumPyArrayToRaster(outArrayPET, lowerLeft, cellSize)
&nbsp; File "C:\Program Files (x86)\ArcGIS\Desktop10.3\ArcPy\arcpy\__init__.py", line 2292, in NumPyArrayToRaster
&nbsp;&nbsp;&nbsp; return _NumPyArrayToRaster(*args, **kwargs)
TypeError: Cannot create raster for numpy array.<SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

I don't know how to fix this error. Are my arrays to big to fit into RAM? Do I have to clear or release the memory after each iteration? Do I need to go multiprocessing?

I will try to subsample my arrays and return with the results.

DanPatterson_Retired

here is a simpler version explaining what happens to x, i and j

a <SPAN class="operator token">=</SPAN> np<SPAN class="punctuation token">.</SPAN>arange<SPAN class="punctuation token">(</SPAN><SPAN class="number token">4</SPAN><SPAN class="operator token">*</SPAN><SPAN class="number token">6</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">.</SPAN>reshape<SPAN class="punctuation token">(</SPAN><SPAN class="number token">4</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">6</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">[</SPAN><SPAN class="punctuation token">:</SPAN><SPAN class="number token">3</SPAN><SPAN class="punctuation token">,</SPAN><SPAN class="punctuation token">:</SPAN><SPAN class="number token">3</SPAN><SPAN class="punctuation token">]</SPAN>
result <SPAN class="operator token">=</SPAN> <SPAN class="punctuation token">[</SPAN><SPAN class="punctuation token">]</SPAN>
b <SPAN class="operator token">=</SPAN> a <SPAN class="operator token">+</SPAN> <SPAN class="number token">2</SPAN>&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="comment token"># just add 2 to array a to make b different than a</SPAN>
<SPAN class="keyword token">print</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="string token">"array a\n{}\narray b\n{}"</SPAN><SPAN class="punctuation token">.</SPAN>format<SPAN class="punctuation token">(</SPAN>a<SPAN class="punctuation token">,</SPAN> b<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">)</SPAN>
<SPAN class="keyword token">for</SPAN> x <SPAN class="keyword token">in</SPAN> range<SPAN class="punctuation token">(</SPAN><SPAN class="number token">3</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">:</SPAN>
&nbsp;&nbsp;&nbsp; <SPAN class="keyword token">for</SPAN> i <SPAN class="keyword token">in</SPAN> range<SPAN class="punctuation token">(</SPAN><SPAN class="number token">2</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">:</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="keyword token">for</SPAN> j <SPAN class="keyword token">in</SPAN> range<SPAN class="punctuation token">(</SPAN><SPAN class="number token">2</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">:</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; v1 <SPAN class="operator token">=</SPAN> a<SPAN class="punctuation token">[</SPAN>i<SPAN class="punctuation token">,</SPAN>j<SPAN class="punctuation token">]</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; v1 <SPAN class="operator token">=</SPAN> v1<SPAN class="operator token">*</SPAN>x
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; v2 <SPAN class="operator token">=</SPAN> b<SPAN class="punctuation token">[</SPAN>i<SPAN class="punctuation token">,</SPAN>j<SPAN class="punctuation token">]</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; tot <SPAN class="operator token">=</SPAN> v1 <SPAN class="operator token">+</SPAN> v2
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="keyword token">print</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="string token">"x... {} v1*x +&nbsp; v2 =>&nbsp; {} + {} = {}"</SPAN><SPAN class="punctuation token">.</SPAN>format<SPAN class="punctuation token">(</SPAN>x<SPAN class="punctuation token">,</SPAN> v1<SPAN class="punctuation token">,</SPAN> v2<SPAN class="punctuation token">,</SPAN> tot<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">)</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; result<SPAN class="punctuation token">.</SPAN>append<SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">[</SPAN>x<SPAN class="punctuation token">,</SPAN> i<SPAN class="punctuation token">,</SPAN> j<SPAN class="punctuation token">,</SPAN> v1<SPAN class="punctuation token">,</SPAN> v2<SPAN class="punctuation token">,</SPAN> tot<SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">)</SPAN>
result <SPAN class="operator token">=</SPAN> np<SPAN class="punctuation token">.</SPAN>array<SPAN class="punctuation token">(</SPAN>result<SPAN class="punctuation token">)</SPAN>
<SPAN class="keyword token">print</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="string token">"final result...\n x, i, j, v1, v2, tot\n{}"</SPAN><SPAN class="punctuation token">.</SPAN>format<SPAN class="punctuation token">(</SPAN>result<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

with the result

final result<SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN>
 x<SPAN class="punctuation token">,</SPAN> i<SPAN class="punctuation token">,</SPAN> j<SPAN class="punctuation token">,</SPAN> v1<SPAN class="punctuation token">,</SPAN> v2<SPAN class="punctuation token">,</SPAN> tot
<SPAN class="punctuation token">[</SPAN><SPAN class="punctuation token">[</SPAN> <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">2</SPAN>&nbsp; <SPAN class="number token">2</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN> <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">1</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">3</SPAN>&nbsp; <SPAN class="number token">3</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN> <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">1</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">8</SPAN>&nbsp; <SPAN class="number token">8</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN> <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">1</SPAN>&nbsp; <SPAN class="number token">1</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">9</SPAN>&nbsp; <SPAN class="number token">9</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN> <SPAN class="number token">1</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">2</SPAN>&nbsp; <SPAN class="number token">2</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN> <SPAN class="number token">1</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">1</SPAN>&nbsp; <SPAN class="number token">1</SPAN>&nbsp; <SPAN class="number token">3</SPAN>&nbsp; <SPAN class="number token">4</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN> <SPAN class="number token">1</SPAN>&nbsp; <SPAN class="number token">1</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">6</SPAN>&nbsp; <SPAN class="number token">8</SPAN> <SPAN class="number token">14</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN> <SPAN class="number token">1</SPAN>&nbsp; <SPAN class="number token">1</SPAN>&nbsp; <SPAN class="number token">1</SPAN>&nbsp; <SPAN class="number token">7</SPAN>&nbsp; <SPAN class="number token">9</SPAN> <SPAN class="number token">16</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN> <SPAN class="number token">2</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">2</SPAN>&nbsp; <SPAN class="number token">2</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN> <SPAN class="number token">2</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">1</SPAN>&nbsp; <SPAN class="number token">2</SPAN>&nbsp; <SPAN class="number token">3</SPAN>&nbsp; <SPAN class="number token">5</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN> <SPAN class="number token">2</SPAN>&nbsp; <SPAN class="number token">1</SPAN>&nbsp; <SPAN class="number token">0</SPAN> <SPAN class="number token">12</SPAN>&nbsp; <SPAN class="number token">8</SPAN> <SPAN class="number token">20</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN> <SPAN class="number token">2</SPAN>&nbsp; <SPAN class="number token">1</SPAN>&nbsp; <SPAN class="number token">1</SPAN> <SPAN class="number token">14</SPAN>&nbsp; <SPAN class="number token">9</SPAN> <SPAN class="number token">23</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

DanPatterson_Retired

I am still not sure why you are cycling through one cell in an array.

Here is a simpler demo...

<SPAN class="keyword token">import</SPAN> numpy <SPAN class="keyword token">as</SPAN> np

a <SPAN class="operator token">=</SPAN> np<SPAN class="punctuation token">.</SPAN>arange<SPAN class="punctuation token">(</SPAN><SPAN class="number token">4</SPAN><SPAN class="operator token">*</SPAN><SPAN class="number token">6</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">.</SPAN>reshape<SPAN class="punctuation token">(</SPAN><SPAN class="number token">4</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">6</SPAN><SPAN class="punctuation token">)</SPAN>
result <SPAN class="operator token">=</SPAN> <SPAN class="punctuation token">[</SPAN><SPAN class="punctuation token">]</SPAN>
b <SPAN class="operator token">=</SPAN> a <SPAN class="operator token">+</SPAN> <SPAN class="number token">2</SPAN>&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="comment token"># just add 2 to array a to make b different than a</SPAN>
<SPAN class="keyword token">print</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="string token">"array a\n{}\narray b\n{}"</SPAN><SPAN class="punctuation token">.</SPAN>format<SPAN class="punctuation token">(</SPAN>a<SPAN class="punctuation token">,</SPAN> b<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">)</SPAN>
<SPAN class="keyword token">for</SPAN> i <SPAN class="keyword token">in</SPAN> range<SPAN class="punctuation token">(</SPAN><SPAN class="number token">3</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">:</SPAN>
&nbsp;&nbsp;&nbsp; <SPAN class="keyword token">for</SPAN> j <SPAN class="keyword token">in</SPAN> range<SPAN class="punctuation token">(</SPAN><SPAN class="number token">3</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">:</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; v1 <SPAN class="operator token">=</SPAN> a<SPAN class="punctuation token">[</SPAN>i<SPAN class="punctuation token">,</SPAN>j<SPAN class="punctuation token">]</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; v2 <SPAN class="operator token">=</SPAN> b<SPAN class="punctuation token">[</SPAN>i<SPAN class="punctuation token">,</SPAN>j<SPAN class="punctuation token">]</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; tot <SPAN class="operator token">=</SPAN> v1 <SPAN class="operator token">+</SPAN> v2
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="keyword token">print</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="string token">"v1 + v2 =>&nbsp; {} + {} = {}"</SPAN><SPAN class="punctuation token">.</SPAN>format<SPAN class="punctuation token">(</SPAN>v1<SPAN class="punctuation token">,</SPAN> v2<SPAN class="punctuation token">,</SPAN> tot<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">)</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; result<SPAN class="punctuation token">.</SPAN>append<SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">[</SPAN>i<SPAN class="punctuation token">,</SPAN> j<SPAN class="punctuation token">,</SPAN> v1<SPAN class="punctuation token">,</SPAN> v2<SPAN class="punctuation token">,</SPAN> tot<SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">)</SPAN>
result <SPAN class="operator token">=</SPAN> np<SPAN class="punctuation token">.</SPAN>array<SPAN class="punctuation token">(</SPAN>result<SPAN class="punctuation token">)</SPAN>
<SPAN class="keyword token">print</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="string token">"final result...\n i, j, v1, v2, tot\n{}"</SPAN><SPAN class="punctuation token">.</SPAN>format<SPAN class="punctuation token">(</SPAN>result<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">)</SPAN>‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍<SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

and here is the result

array a
<SPAN class="punctuation token">[</SPAN><SPAN class="punctuation token">[</SPAN> <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">1</SPAN>&nbsp; <SPAN class="number token">2</SPAN>&nbsp; <SPAN class="number token">3</SPAN>&nbsp; <SPAN class="number token">4</SPAN>&nbsp; <SPAN class="number token">5</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN> <SPAN class="number token">6</SPAN>&nbsp; <SPAN class="number token">7</SPAN>&nbsp; <SPAN class="number token">8</SPAN>&nbsp; <SPAN class="number token">9</SPAN> <SPAN class="number token">10</SPAN> <SPAN class="number token">11</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN><SPAN class="number token">12</SPAN> <SPAN class="number token">13</SPAN> <SPAN class="number token">14</SPAN> <SPAN class="number token">15</SPAN> <SPAN class="number token">16</SPAN> <SPAN class="number token">17</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN><SPAN class="number token">18</SPAN> <SPAN class="number token">19</SPAN> <SPAN class="number token">20</SPAN> <SPAN class="number token">21</SPAN> <SPAN class="number token">22</SPAN> <SPAN class="number token">23</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">]</SPAN>
array b
<SPAN class="punctuation token">[</SPAN><SPAN class="punctuation token">[</SPAN> <SPAN class="number token">2</SPAN>&nbsp; <SPAN class="number token">3</SPAN>&nbsp; <SPAN class="number token">4</SPAN>&nbsp; <SPAN class="number token">5</SPAN>&nbsp; <SPAN class="number token">6</SPAN>&nbsp; <SPAN class="number token">7</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN> <SPAN class="number token">8</SPAN>&nbsp; <SPAN class="number token">9</SPAN> <SPAN class="number token">10</SPAN> <SPAN class="number token">11</SPAN> <SPAN class="number token">12</SPAN> <SPAN class="number token">13</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN><SPAN class="number token">14</SPAN> <SPAN class="number token">15</SPAN> <SPAN class="number token">16</SPAN> <SPAN class="number token">17</SPAN> <SPAN class="number token">18</SPAN> <SPAN class="number token">19</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN><SPAN class="number token">20</SPAN> <SPAN class="number token">21</SPAN> <SPAN class="number token">22</SPAN> <SPAN class="number token">23</SPAN> <SPAN class="number token">24</SPAN> <SPAN class="number token">25</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">]</SPAN>
v1 <SPAN class="operator token">+</SPAN> v2 <SPAN class="operator token">=</SPAN><SPAN class="operator token">></SPAN>&nbsp; <SPAN class="number token">0</SPAN> <SPAN class="operator token">+</SPAN> <SPAN class="number token">2</SPAN> <SPAN class="operator token">=</SPAN> <SPAN class="number token">2</SPAN>
v1 <SPAN class="operator token">+</SPAN> v2 <SPAN class="operator token">=</SPAN><SPAN class="operator token">></SPAN>&nbsp; <SPAN class="number token">1</SPAN> <SPAN class="operator token">+</SPAN> <SPAN class="number token">3</SPAN> <SPAN class="operator token">=</SPAN> <SPAN class="number token">4</SPAN>
v1 <SPAN class="operator token">+</SPAN> v2 <SPAN class="operator token">=</SPAN><SPAN class="operator token">></SPAN>&nbsp; <SPAN class="number token">2</SPAN> <SPAN class="operator token">+</SPAN> <SPAN class="number token">4</SPAN> <SPAN class="operator token">=</SPAN> <SPAN class="number token">6</SPAN>
v1 <SPAN class="operator token">+</SPAN> v2 <SPAN class="operator token">=</SPAN><SPAN class="operator token">></SPAN>&nbsp; <SPAN class="number token">6</SPAN> <SPAN class="operator token">+</SPAN> <SPAN class="number token">8</SPAN> <SPAN class="operator token">=</SPAN> <SPAN class="number token">14</SPAN>
v1 <SPAN class="operator token">+</SPAN> v2 <SPAN class="operator token">=</SPAN><SPAN class="operator token">></SPAN>&nbsp; <SPAN class="number token">7</SPAN> <SPAN class="operator token">+</SPAN> <SPAN class="number token">9</SPAN> <SPAN class="operator token">=</SPAN> <SPAN class="number token">16</SPAN>
v1 <SPAN class="operator token">+</SPAN> v2 <SPAN class="operator token">=</SPAN><SPAN class="operator token">></SPAN>&nbsp; <SPAN class="number token">8</SPAN> <SPAN class="operator token">+</SPAN> <SPAN class="number token">10</SPAN> <SPAN class="operator token">=</SPAN> <SPAN class="number token">18</SPAN>
v1 <SPAN class="operator token">+</SPAN> v2 <SPAN class="operator token">=</SPAN><SPAN class="operator token">></SPAN>&nbsp; <SPAN class="number token">12</SPAN> <SPAN class="operator token">+</SPAN> <SPAN class="number token">14</SPAN> <SPAN class="operator token">=</SPAN> <SPAN class="number token">26</SPAN>
v1 <SPAN class="operator token">+</SPAN> v2 <SPAN class="operator token">=</SPAN><SPAN class="operator token">></SPAN>&nbsp; <SPAN class="number token">13</SPAN> <SPAN class="operator token">+</SPAN> <SPAN class="number token">15</SPAN> <SPAN class="operator token">=</SPAN> <SPAN class="number token">28</SPAN>
v1 <SPAN class="operator token">+</SPAN> v2 <SPAN class="operator token">=</SPAN><SPAN class="operator token">></SPAN>&nbsp; <SPAN class="number token">14</SPAN> <SPAN class="operator token">+</SPAN> <SPAN class="number token">16</SPAN> <SPAN class="operator token">=</SPAN> <SPAN class="number token">30</SPAN>
final result<SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN>
 i<SPAN class="punctuation token">,</SPAN> j<SPAN class="punctuation token">,</SPAN> v1<SPAN class="punctuation token">,</SPAN> v2<SPAN class="punctuation token">,</SPAN> tot
<SPAN class="punctuation token">[</SPAN><SPAN class="punctuation token">[</SPAN> <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">2</SPAN>&nbsp; <SPAN class="number token">2</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN> <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">1</SPAN>&nbsp; <SPAN class="number token">1</SPAN>&nbsp; <SPAN class="number token">3</SPAN>&nbsp; <SPAN class="number token">4</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN> <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">2</SPAN>&nbsp; <SPAN class="number token">2</SPAN>&nbsp; <SPAN class="number token">4</SPAN>&nbsp; <SPAN class="number token">6</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN> <SPAN class="number token">1</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">6</SPAN>&nbsp; <SPAN class="number token">8</SPAN> <SPAN class="number token">14</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN> <SPAN class="number token">1</SPAN>&nbsp; <SPAN class="number token">1</SPAN>&nbsp; <SPAN class="number token">7</SPAN>&nbsp; <SPAN class="number token">9</SPAN> <SPAN class="number token">16</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN> <SPAN class="number token">1</SPAN>&nbsp; <SPAN class="number token">2</SPAN>&nbsp; <SPAN class="number token">8</SPAN> <SPAN class="number token">10</SPAN> <SPAN class="number token">18</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN> <SPAN class="number token">2</SPAN>&nbsp; <SPAN class="number token">0</SPAN> <SPAN class="number token">12</SPAN> <SPAN class="number token">14</SPAN> <SPAN class="number token">26</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN> <SPAN class="number token">2</SPAN>&nbsp; <SPAN class="number token">1</SPAN> <SPAN class="number token">13</SPAN> <SPAN class="number token">15</SPAN> <SPAN class="number token">28</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN> <SPAN class="number token">2</SPAN>&nbsp; <SPAN class="number token">2</SPAN> <SPAN class="number token">14</SPAN> <SPAN class="number token">16</SPAN> <SPAN class="number token">30</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">]</SPAN>
‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍<SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

I suspect this isn't what you want because of your slicing the arrays by

So again, since you only have a 2D array, why are you slicing out single cells.

EDIT

Why don't you slice out your array and show some real numbers with a result, say for the first 5 values for X.

You can subsample your arrays, using slicing as follows

<SPAN class="operator token">>></SPAN><SPAN class="operator token">></SPAN> a
array<SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">[</SPAN><SPAN class="punctuation token">[</SPAN> <SPAN class="number token">0</SPAN><SPAN class="punctuation token">,</SPAN>&nbsp; <SPAN class="number token">1</SPAN><SPAN class="punctuation token">,</SPAN>&nbsp; <SPAN class="number token">2</SPAN><SPAN class="punctuation token">,</SPAN>&nbsp; <SPAN class="number token">3</SPAN><SPAN class="punctuation token">,</SPAN>&nbsp; <SPAN class="number token">4</SPAN><SPAN class="punctuation token">,</SPAN>&nbsp; <SPAN class="number token">5</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">,</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="punctuation token">[</SPAN> <SPAN class="number token">6</SPAN><SPAN class="punctuation token">,</SPAN>&nbsp; <SPAN class="number token">7</SPAN><SPAN class="punctuation token">,</SPAN>&nbsp; <SPAN class="number token">8</SPAN><SPAN class="punctuation token">,</SPAN>&nbsp; <SPAN class="number token">9</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">10</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">11</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">,</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="punctuation token">[</SPAN><SPAN class="number token">12</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">13</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">14</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">15</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">16</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">17</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">,</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="punctuation token">[</SPAN><SPAN class="number token">18</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">19</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">20</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">21</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">22</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">23</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">)</SPAN>
<SPAN class="operator token">>></SPAN><SPAN class="operator token">></SPAN> a1 <SPAN class="operator token">=</SPAN> a<SPAN class="punctuation token">[</SPAN><SPAN class="punctuation token">:</SPAN><SPAN class="number token">3</SPAN><SPAN class="punctuation token">,</SPAN><SPAN class="punctuation token">:</SPAN><SPAN class="number token">3</SPAN><SPAN class="punctuation token">]</SPAN>
<SPAN class="operator token">>></SPAN><SPAN class="operator token">></SPAN> b
array<SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">[</SPAN><SPAN class="punctuation token">[</SPAN> <SPAN class="number token">2</SPAN><SPAN class="punctuation token">,</SPAN>&nbsp; <SPAN class="number token">3</SPAN><SPAN class="punctuation token">,</SPAN>&nbsp; <SPAN class="number token">4</SPAN><SPAN class="punctuation token">,</SPAN>&nbsp; <SPAN class="number token">5</SPAN><SPAN class="punctuation token">,</SPAN>&nbsp; <SPAN class="number token">6</SPAN><SPAN class="punctuation token">,</SPAN>&nbsp; <SPAN class="number token">7</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">,</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="punctuation token">[</SPAN> <SPAN class="number token">8</SPAN><SPAN class="punctuation token">,</SPAN>&nbsp; <SPAN class="number token">9</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">10</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">11</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">12</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">13</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">,</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="punctuation token">[</SPAN><SPAN class="number token">14</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">15</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">16</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">17</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">18</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">19</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">,</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="punctuation token">[</SPAN><SPAN class="number token">20</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">21</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">22</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">23</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">24</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">25</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">)</SPAN>
<SPAN class="operator token">>></SPAN><SPAN class="operator token">></SPAN> b1 <SPAN class="operator token">=</SPAN> b<SPAN class="punctuation token">[</SPAN><SPAN class="punctuation token">:</SPAN><SPAN class="number token">3</SPAN><SPAN class="punctuation token">,</SPAN><SPAN class="punctuation token">:</SPAN><SPAN class="number token">3</SPAN><SPAN class="punctuation token">]</SPAN>
<SPAN class="operator token">>></SPAN><SPAN class="operator token">></SPAN> 
<SPAN class="operator token">>></SPAN><SPAN class="operator token">></SPAN> 
<SPAN class="operator token">>></SPAN><SPAN class="operator token">></SPAN> a1
array<SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">[</SPAN><SPAN class="punctuation token">[</SPAN> <SPAN class="number token">0</SPAN><SPAN class="punctuation token">,</SPAN>&nbsp; <SPAN class="number token">1</SPAN><SPAN class="punctuation token">,</SPAN>&nbsp; <SPAN class="number token">2</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">,</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="punctuation token">[</SPAN> <SPAN class="number token">6</SPAN><SPAN class="punctuation token">,</SPAN>&nbsp; <SPAN class="number token">7</SPAN><SPAN class="punctuation token">,</SPAN>&nbsp; <SPAN class="number token">8</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">,</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="punctuation token">[</SPAN><SPAN class="number token">12</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">13</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">14</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">)</SPAN>
<SPAN class="operator token">>></SPAN><SPAN class="operator token">></SPAN> b1
array<SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">[</SPAN><SPAN class="punctuation token">[</SPAN> <SPAN class="number token">2</SPAN><SPAN class="punctuation token">,</SPAN>&nbsp; <SPAN class="number token">3</SPAN><SPAN class="punctuation token">,</SPAN>&nbsp; <SPAN class="number token">4</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">,</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="punctuation token">[</SPAN> <SPAN class="number token">8</SPAN><SPAN class="punctuation token">,</SPAN>&nbsp; <SPAN class="number token">9</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">10</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">,</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="punctuation token">[</SPAN><SPAN class="number token">14</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">15</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">16</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

XinXia1

I'm not sure what you mean when you say running calculation on the array. I'm trying to do exactly what your code is showing.

Each array contains floats and have the following:

array dimensions (ndim) = 2

array shape (shape) = (5400, 6318)

I actually don't want my array C (outArrayPET) to be a clone of inarrayPETnorm I didn't know how to initialize it. I'll try doing what you have with:

c <SPAN class="" style="color: #a67f59; background: rgba(255, 255, 255, 0.498039); border: 0px; font-weight: inherit;">=</SPAN> np<SPAN class="" style="color: #999999; border: 0px; font-weight: inherit;">.</SPAN>zeros_like<SPAN class="" style="color: #999999; border: 0px; font-weight: inherit;">(</SPAN>b<SPAN class="" style="color: #999999; border: 0px; font-weight: inherit;">)</SPAN>

Also could you explain what the + 2 is for in line 5 of your code:

b <SPAN class="" style="color: #a67f59; background: rgba(255, 255, 255, 0.498039); border: 0px; font-weight: inherit;">=</SPAN> np<SPAN class="" style="color: #999999; border: 0px; font-weight: inherit;">.</SPAN>arange<SPAN class="" style="color: #999999; border: 0px; font-weight: inherit;">(</SPAN>rows<SPAN class="" style="color: #a67f59; background: rgba(255, 255, 255, 0.498039); border: 0px; font-weight: inherit;">*</SPAN>cols<SPAN class="" style="color: #999999; border: 0px; font-weight: inherit;">)</SPAN><SPAN class="" style="color: #999999; border: 0px; font-weight: inherit;">.</SPAN>reshape<SPAN class="" style="color: #999999; border: 0px; font-weight: inherit;">(</SPAN>rows<SPAN class="" style="color: #999999; border: 0px; font-weight: inherit;">,</SPAN> cols<SPAN class="" style="color: #999999; border: 0px; font-weight: inherit;">)</SPAN> <SPAN class="" style="color: #a67f59; background: rgba(255, 255, 255, 0.498039); border: 0px; font-weight: inherit;">+</SPAN> <SPAN class="" style="color: #990000; border: 0px; font-weight: inherit;">2</SPAN>

I ran this code again with print statements:

<SPAN class="keyword token">import</SPAN> arcpy
<SPAN class="keyword token">import</SPAN> numpy

inRasPETcgcm <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>Raster<SPAN class="punctuation token">(</SPAN><SPAN class="string token">"C:/VegModel/CCSSRawData.gdb/petCgcmRS100Clip"</SPAN><SPAN class="punctuation token">)</SPAN>
inRasPETnorm <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>Raster<SPAN class="punctuation token">(</SPAN><SPAN class="string token">"C:/VegModel/CCSSRawData.gdb/petNormRS100Clip"</SPAN><SPAN class="punctuation token">)</SPAN>

lowerLeft <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>Point<SPAN class="punctuation token">(</SPAN>inRasPETnorm<SPAN class="punctuation token">.</SPAN>extent<SPAN class="punctuation token">.</SPAN>XMin<SPAN class="punctuation token">,</SPAN>inRasPETnorm<SPAN class="punctuation token">.</SPAN>extent<SPAN class="punctuation token">.</SPAN>YMin<SPAN class="punctuation token">)</SPAN>
cellSize <SPAN class="operator token">=</SPAN> inRasPETnorm<SPAN class="punctuation token">.</SPAN>meanCellWidth

inArrayPETcgcm <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>RasterToNumPyArray<SPAN class="punctuation token">(</SPAN>inRasPETcgcm<SPAN class="punctuation token">)</SPAN>

inArrayPETnorm <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>RasterToNumPyArray<SPAN class="punctuation token">(</SPAN>inRasPETnorm<SPAN class="punctuation token">)</SPAN>

outArrayPET <SPAN class="operator token">=</SPAN> inArrayPETnorm

<SPAN class="keyword token">for</SPAN> x <SPAN class="keyword token">in</SPAN> range <SPAN class="punctuation token">(</SPAN><SPAN class="number token">1</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">3</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">:</SPAN>
&nbsp;&nbsp;&nbsp; <SPAN class="keyword token">for</SPAN> i <SPAN class="keyword token">in</SPAN> range<SPAN class="punctuation token">(</SPAN><SPAN class="number token">0</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">2</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">:</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="keyword token">for</SPAN> j <SPAN class="keyword token">in</SPAN> range<SPAN class="punctuation token">(</SPAN><SPAN class="number token">0</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">2</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">:</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; value1 <SPAN class="operator token">=</SPAN> inArrayPETcgcm<SPAN class="punctuation token">[</SPAN>i<SPAN class="punctuation token">,</SPAN> j<SPAN class="punctuation token">]</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; value2 <SPAN class="operator token">=</SPAN> inArrayPETnorm<SPAN class="punctuation token">[</SPAN>i<SPAN class="punctuation token">,</SPAN> j<SPAN class="punctuation token">]</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="keyword token">print</SPAN> <SPAN class="string token">"value1 before calculation is: "</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="keyword token">print</SPAN> value1
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="keyword token">print</SPAN> <SPAN class="string token">"value2 is before calculation: "</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="keyword token">print</SPAN> value2

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; value1 <SPAN class="operator token">=</SPAN> value1 <SPAN class="operator token">*</SPAN> x

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="keyword token">print</SPAN> <SPAN class="string token">"value1 after multiplication is: "</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="keyword token">print</SPAN> value1
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; value3 <SPAN class="operator token">=</SPAN> value1 <SPAN class="operator token">+</SPAN> value2

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="keyword token">print</SPAN> <SPAN class="string token">"value3 after addition is: "</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="keyword token">print</SPAN> value3

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; outArrayPET<SPAN class="punctuation token">[</SPAN>i<SPAN class="punctuation token">,</SPAN> j<SPAN class="punctuation token">]</SPAN> <SPAN class="operator token">=</SPAN> value3
&nbsp;&nbsp;&nbsp; 
&nbsp;&nbsp;&nbsp; newRasPET <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>NumPyArrayToRaster<SPAN class="punctuation token">(</SPAN>outArrayPET<SPAN class="punctuation token">,</SPAN> lowerLeft<SPAN class="punctuation token">,</SPAN> cellSize<SPAN class="punctuation token">)</SPAN>
&nbsp;&nbsp;&nbsp; newRasPET<SPAN class="punctuation token">.</SPAN>save<SPAN class="punctuation token">(</SPAN><SPAN class="string token">"C:/VegModel/Revise.gdb/pet100ReviseYear%dB"</SPAN> <SPAN class="operator token">%</SPAN>x<SPAN class="punctuation token">)</SPAN>


<SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

value2 has somehow changed in the second iteration (the bottom 4 groups) of the x loop. The output gave me the following:

value1 before calculation is: 
2.50291
value2 is before calculation: 
453.256
value1 after multiplication is: 
2.50291275978
value3 after addition is: 
455.759107828


value1 before calculation is: 
2.50291
value2 is before calculation: 
453.256
value1 after multiplication is: 
2.50291275978
value3 after addition is: 
455.759107828


value1 before calculation is: 
2.50291
value2 is before calculation: 
453.256
value1 after multiplication is: 
2.50291275978
value3 after addition is: 
455.759107828


value1 before calculation is: 
2.50291
value2 is before calculation: 
453.256
value1 after multiplication is: 
2.50291275978
value3 after addition is: 
455.759107828


value1 before calculation is: 
2.50291
value2 is before calculation: 
455.759
value1 after multiplication is: 
5.00582551956
value3 after addition is: 
460.764919758


value1 before calculation is: 
2.50291
value2 is before calculation: 
455.759
value1 after multiplication is: 
5.00582551956
value3 after addition is: 
460.764919758


value1 before calculation is: 
2.50291
value2 is before calculation: 
455.759
value1 after multiplication is: 
5.00582551956
value3 after addition is: 
460.764919758


value1 before calculation is: 
2.50291
value2 is before calculation: 
455.759
value1 after multiplication is: 
5.00582551956
value3 after addition is: 
460.764919758

‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍<SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

I have no clue where the value2 of 455.759 is coming from in the second iteration of the x loop

DanPatterson_Retired

a simpler version of what you have so far..

rows <SPAN class="operator token">=</SPAN> <SPAN class="number token">4</SPAN>
cols <SPAN class="operator token">=</SPAN> <SPAN class="number token">6</SPAN>
N <SPAN class="operator token">=</SPAN> <SPAN class="number token">5</SPAN>&nbsp;&nbsp;&nbsp; <SPAN class="comment token"># your 51</SPAN>
a <SPAN class="operator token">=</SPAN> np<SPAN class="punctuation token">.</SPAN>arange<SPAN class="punctuation token">(</SPAN>rows<SPAN class="operator token">*</SPAN>cols<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">.</SPAN>reshape<SPAN class="punctuation token">(</SPAN>rows<SPAN class="punctuation token">,</SPAN> cols<SPAN class="punctuation token">)</SPAN>
b <SPAN class="operator token">=</SPAN> np<SPAN class="punctuation token">.</SPAN>arange<SPAN class="punctuation token">(</SPAN>rows<SPAN class="operator token">*</SPAN>cols<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">.</SPAN>reshape<SPAN class="punctuation token">(</SPAN>rows<SPAN class="punctuation token">,</SPAN> cols<SPAN class="punctuation token">)</SPAN> <SPAN class="operator token">+</SPAN> <SPAN class="number token">2</SPAN>
c <SPAN class="operator token">=</SPAN> np<SPAN class="punctuation token">.</SPAN>zeros_like<SPAN class="punctuation token">(</SPAN>b<SPAN class="punctuation token">)</SPAN>
<SPAN class="keyword token">print</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="string token">"Input arrays... a and b\n{}\n...\n{}"</SPAN><SPAN class="punctuation token">.</SPAN>format<SPAN class="punctuation token">(</SPAN>a<SPAN class="punctuation token">,</SPAN> b<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">)</SPAN>
<SPAN class="keyword token">for</SPAN> x <SPAN class="keyword token">in</SPAN> range <SPAN class="punctuation token">(</SPAN><SPAN class="number token">1</SPAN><SPAN class="punctuation token">,</SPAN> N<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">:</SPAN>
&nbsp;&nbsp;&nbsp; <SPAN class="keyword token">for</SPAN> i <SPAN class="keyword token">in</SPAN> range<SPAN class="punctuation token">(</SPAN><SPAN class="number token">0</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">2</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">:</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="keyword token">for</SPAN> j <SPAN class="keyword token">in</SPAN> range<SPAN class="punctuation token">(</SPAN><SPAN class="number token">0</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">2</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">:</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; value1 <SPAN class="operator token">=</SPAN> a<SPAN class="punctuation token">[</SPAN>i<SPAN class="punctuation token">,</SPAN> j<SPAN class="punctuation token">]</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; value2 <SPAN class="operator token">=</SPAN> b<SPAN class="punctuation token">[</SPAN>i<SPAN class="punctuation token">,</SPAN> j<SPAN class="punctuation token">]</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; value1 <SPAN class="operator token">=</SPAN> value1 <SPAN class="operator token">*</SPAN> x
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; value3 <SPAN class="operator token">=</SPAN> value1 <SPAN class="operator token">+</SPAN> value2
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; c<SPAN class="punctuation token">[</SPAN>i<SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">[</SPAN>j<SPAN class="punctuation token">]</SPAN> <SPAN class="operator token">=</SPAN> value3&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="comment token"># note change</SPAN>
&nbsp;&nbsp;&nbsp; <SPAN class="keyword token">print</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="string token">"c at {}, {}\n{}"</SPAN><SPAN class="punctuation token">.</SPAN>format<SPAN class="punctuation token">(</SPAN>i<SPAN class="punctuation token">,</SPAN> j<SPAN class="punctuation token">,</SPAN> c<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

and the results so far

Input arrays<SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN> a <SPAN class="operator token">and</SPAN> b
<SPAN class="punctuation token">[</SPAN><SPAN class="punctuation token">[</SPAN> <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">1</SPAN>&nbsp; <SPAN class="number token">2</SPAN>&nbsp; <SPAN class="number token">3</SPAN>&nbsp; <SPAN class="number token">4</SPAN>&nbsp; <SPAN class="number token">5</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN> <SPAN class="number token">6</SPAN>&nbsp; <SPAN class="number token">7</SPAN>&nbsp; <SPAN class="number token">8</SPAN>&nbsp; <SPAN class="number token">9</SPAN> <SPAN class="number token">10</SPAN> <SPAN class="number token">11</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN><SPAN class="number token">12</SPAN> <SPAN class="number token">13</SPAN> <SPAN class="number token">14</SPAN> <SPAN class="number token">15</SPAN> <SPAN class="number token">16</SPAN> <SPAN class="number token">17</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN><SPAN class="number token">18</SPAN> <SPAN class="number token">19</SPAN> <SPAN class="number token">20</SPAN> <SPAN class="number token">21</SPAN> <SPAN class="number token">22</SPAN> <SPAN class="number token">23</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">]</SPAN>
<SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN>
<SPAN class="punctuation token">[</SPAN><SPAN class="punctuation token">[</SPAN> <SPAN class="number token">2</SPAN>&nbsp; <SPAN class="number token">3</SPAN>&nbsp; <SPAN class="number token">4</SPAN>&nbsp; <SPAN class="number token">5</SPAN>&nbsp; <SPAN class="number token">6</SPAN>&nbsp; <SPAN class="number token">7</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN> <SPAN class="number token">8</SPAN>&nbsp; <SPAN class="number token">9</SPAN> <SPAN class="number token">10</SPAN> <SPAN class="number token">11</SPAN> <SPAN class="number token">12</SPAN> <SPAN class="number token">13</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN><SPAN class="number token">14</SPAN> <SPAN class="number token">15</SPAN> <SPAN class="number token">16</SPAN> <SPAN class="number token">17</SPAN> <SPAN class="number token">18</SPAN> <SPAN class="number token">19</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN><SPAN class="number token">20</SPAN> <SPAN class="number token">21</SPAN> <SPAN class="number token">22</SPAN> <SPAN class="number token">23</SPAN> <SPAN class="number token">24</SPAN> <SPAN class="number token">25</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">]</SPAN>
c at <SPAN class="number token">1</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">1</SPAN>
<SPAN class="punctuation token">[</SPAN><SPAN class="punctuation token">[</SPAN> <SPAN class="number token">2</SPAN>&nbsp; <SPAN class="number token">4</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN><SPAN class="number token">14</SPAN> <SPAN class="number token">16</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN> <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN> <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">]</SPAN>
c at <SPAN class="number token">1</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">1</SPAN>
<SPAN class="punctuation token">[</SPAN><SPAN class="punctuation token">[</SPAN> <SPAN class="number token">2</SPAN>&nbsp; <SPAN class="number token">5</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN><SPAN class="number token">20</SPAN> <SPAN class="number token">23</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN> <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN> <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">]</SPAN>
c at <SPAN class="number token">1</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">1</SPAN>
<SPAN class="punctuation token">[</SPAN><SPAN class="punctuation token">[</SPAN> <SPAN class="number token">2</SPAN>&nbsp; <SPAN class="number token">6</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN><SPAN class="number token">26</SPAN> <SPAN class="number token">30</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN> <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN> <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">]</SPAN>
c at <SPAN class="number token">1</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">1</SPAN>
<SPAN class="punctuation token">[</SPAN><SPAN class="punctuation token">[</SPAN> <SPAN class="number token">2</SPAN>&nbsp; <SPAN class="number token">7</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN><SPAN class="number token">32</SPAN> <SPAN class="number token">37</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN> <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN><SPAN class="punctuation token">]</SPAN>
 <SPAN class="punctuation token">[</SPAN> <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN>&nbsp; <SPAN class="number token">0</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">]</SPAN>
<SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

which isn't what you want. So if the output array c, which is your outArrayPet which is a clone of inarrayPetNorm.

Could you provide some insight on...

the array dimensions (ie a.ndim)
What is each array's shape (ie a.shape )
are you trying to perform some sort of running calculation on the array?

XinXia1

Hi Dan,

I want the file saved after the i loop is completed or after each iteration of the x loop. The intent is that I have raster A and B. I need to multiple 1, 2, 3, ... 48, 49, 50 to raster A and add the result to raster B. I have outlined what I have tried below.

The initial code I tried is this:

<SPAN class="keyword token">import</SPAN> arcpy
<SPAN class="keyword token">import</SPAN> numpy

inRasPETcgcm <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>Raster<SPAN class="punctuation token">(</SPAN><SPAN class="string token">"C:/VegModel/CCSSRawData.gdb/petCgcmRS100Clip"</SPAN><SPAN class="punctuation token">)</SPAN>
inRasPETnorm <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>Raster<SPAN class="punctuation token">(</SPAN><SPAN class="string token">"C:/VegModel/CCSSRawData.gdb/petNormRS100Clip"</SPAN><SPAN class="punctuation token">)</SPAN>

lowerLeft <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>Point<SPAN class="punctuation token">(</SPAN>inRasPETnorm<SPAN class="punctuation token">.</SPAN>extent<SPAN class="punctuation token">.</SPAN>XMin<SPAN class="punctuation token">,</SPAN>inRasPETnorm<SPAN class="punctuation token">.</SPAN>extent<SPAN class="punctuation token">.</SPAN>YMin<SPAN class="punctuation token">)</SPAN>
cellSize <SPAN class="operator token">=</SPAN> inRasPETnorm<SPAN class="punctuation token">.</SPAN>meanCellWidth

inArrayPETcgcm <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>RasterToNumPyArray<SPAN class="punctuation token">(</SPAN>inRasPETcgcm<SPAN class="punctuation token">)</SPAN>

inArrayPETnorm <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>RasterToNumPyArray<SPAN class="punctuation token">(</SPAN>inRasPETnorm<SPAN class="punctuation token">)</SPAN>


<SPAN class="keyword token">for</SPAN> x <SPAN class="keyword token">in</SPAN> range <SPAN class="punctuation token">(</SPAN><SPAN class="number token">1</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">51</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">:</SPAN>
&nbsp;&nbsp;&nbsp; inArrayPETcgcm <SPAN class="operator token">=</SPAN> inArrayPETcgcm <SPAN class="operator token">*</SPAN> x

&nbsp;&nbsp;&nbsp; outArrayPET <SPAN class="operator token">=</SPAN> inArrayPETnorm <SPAN class="operator token">+</SPAN> inArrayPETcgcm
&nbsp;&nbsp;&nbsp; 
&nbsp;&nbsp;&nbsp; newRasPET <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>NumPyArrayToRaster<SPAN class="punctuation token">(</SPAN>outArrayPET<SPAN class="punctuation token">,</SPAN> lowerLeft<SPAN class="punctuation token">,</SPAN> cellSize<SPAN class="punctuation token">)</SPAN>
&nbsp;&nbsp;&nbsp; newRasPET<SPAN class="punctuation token">.</SPAN>save<SPAN class="punctuation token">(</SPAN><SPAN class="string token">"C:/VegModel/Revise.gdb/pet100ReviseYear%dB"</SPAN> <SPAN class="operator token">%</SPAN>x<SPAN class="punctuation token">)</SPAN>

<SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

But that code crashes after 2 iterations and give an error message like this:

Traceback (most recent call last):
&nbsp; File "C:\VegModel\PETyearlyChange.py", line 20, in <module>
&nbsp;&nbsp;&nbsp; newRasPET = arcpy.NumPyArrayToRaster(outArrayPET, lowerLeft, cellSize)
&nbsp; File "C:\Program Files (x86)\ArcGIS\Desktop10.3\ArcPy\arcpy\__init__.py", line 2292, in NumPyArrayToRaster
&nbsp;&nbsp;&nbsp; return _NumPyArrayToRaster(*args, **kwargs)
TypeError: Cannot create raster for numpy array.<SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

Plus, of the 2 rasters that got saved before crashing only the raster in the first iteration is correct. So then I tried code that looks like this:

<SPAN class="keyword token">import</SPAN> arcpy
<SPAN class="keyword token">import</SPAN> numpy

inRasPETcgcm <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>Raster<SPAN class="punctuation token">(</SPAN><SPAN class="string token">"C:/VegModel/CCSSRawData.gdb/petCgcmRS100Clip"</SPAN><SPAN class="punctuation token">)</SPAN>
inRasPETnorm <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>Raster<SPAN class="punctuation token">(</SPAN><SPAN class="string token">"C:/VegModel/CCSSRawData.gdb/petNormRS100Clip"</SPAN><SPAN class="punctuation token">)</SPAN>

lowerLeft <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>Point<SPAN class="punctuation token">(</SPAN>inRasPETnorm<SPAN class="punctuation token">.</SPAN>extent<SPAN class="punctuation token">.</SPAN>XMin<SPAN class="punctuation token">,</SPAN>inRasPETnorm<SPAN class="punctuation token">.</SPAN>extent<SPAN class="punctuation token">.</SPAN>YMin<SPAN class="punctuation token">)</SPAN>
cellSize <SPAN class="operator token">=</SPAN> inRasPETnorm<SPAN class="punctuation token">.</SPAN>meanCellWidth

inArrayPETcgcm <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>RasterToNumPyArray<SPAN class="punctuation token">(</SPAN>inRasPETcgcm<SPAN class="punctuation token">)</SPAN>

inArrayPETnorm <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>RasterToNumPyArray<SPAN class="punctuation token">(</SPAN>inRasPETnorm<SPAN class="punctuation token">)</SPAN>

rasHeight<SPAN class="punctuation token">,</SPAN> rasWidth <SPAN class="operator token">=</SPAN> inArrayPETnorm<SPAN class="punctuation token">.</SPAN>shape

outArrayPET <SPAN class="operator token">=</SPAN> inArrayPETnorm

<SPAN class="keyword token">for</SPAN> x <SPAN class="keyword token">in</SPAN> range <SPAN class="punctuation token">(</SPAN><SPAN class="number token">1</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">51</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">:</SPAN>
&nbsp;&nbsp;&nbsp; <SPAN class="keyword token">for</SPAN> i <SPAN class="keyword token">in</SPAN> range<SPAN class="punctuation token">(</SPAN><SPAN class="number token">0</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">2</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">:</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="keyword token">for</SPAN> j <SPAN class="keyword token">in</SPAN> range<SPAN class="punctuation token">(</SPAN><SPAN class="number token">0</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">2</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">:</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; value1 <SPAN class="operator token">=</SPAN> inArrayPETcgcm<SPAN class="punctuation token">[</SPAN>i<SPAN class="punctuation token">,</SPAN> j<SPAN class="punctuation token">]</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; value2 <SPAN class="operator token">=</SPAN> inArrayPETnorm<SPAN class="punctuation token">[</SPAN>i<SPAN class="punctuation token">,</SPAN> j<SPAN class="punctuation token">]</SPAN>

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; value1 <SPAN class="operator token">=</SPAN> value1 <SPAN class="operator token">*</SPAN> x

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; value3 <SPAN class="operator token">=</SPAN> value1 <SPAN class="operator token">+</SPAN> value2

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; outArrayPET<SPAN class="punctuation token">[</SPAN>i<SPAN class="punctuation token">,</SPAN> j<SPAN class="punctuation token">]</SPAN> <SPAN class="operator token">=</SPAN> value3
&nbsp;&nbsp;&nbsp; 
&nbsp;&nbsp;&nbsp; newRasPET <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>NumPyArrayToRaster<SPAN class="punctuation token">(</SPAN>outArrayPET<SPAN class="punctuation token">,</SPAN> lowerLeft<SPAN class="punctuation token">,</SPAN> cellSize<SPAN class="punctuation token">)</SPAN>
&nbsp;&nbsp;&nbsp; newRasPET<SPAN class="punctuation token">.</SPAN>save<SPAN class="punctuation token">(</SPAN><SPAN class="string token">"C:/VegModel/Revise.gdb/pet100ReviseYear%dB"</SPAN> <SPAN class="operator token">%</SPAN>x<SPAN class="punctuation token">)</SPAN>

<SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

This code is able to make it to 50 without crashing. It also doesn't use Decimal. But again, only the raster from the first iteration is correct.

XinXia1

Hi Dan,

Thank you, I understand what you are staying about not needing the Decimal module. However, I have run it without the using Decimal and I am still only getting a correct raster on the first iteration of the loop at line 27. I want to save each iteration to a new file after the outer most for loop at line 27. If I indent it more doesn't it mean I'll be saving each iteration to a new file on the inner nested for loops?

DanPatterson_Retired

well if you are trying to save each iteration to a new file, then your last 2 lines need to be indented more since they are outside of the loop it appears.

And again, dump the Decimal module... it is giving you false precision. Rasters may be 32 bit floats (ie. in the case of esri grids)..., numpy arrays 64 bit at least then back to a raster...

Finally, if you are working with arrays, you don't work on a cell-by-cell basis as in my example...I haven't examined your code closely, to see what its intent was...just got caught up on the false precision

XinXia1

Hi Dan,

Thank you for the tip. I did try it also without using the Decimal module, which works fine. However, my problem is that I am only getting a correct raster result in the first loop through at line 27. All subsequent iterations gives me the wrong values in the rasters, which I have checked by using the identify tool and picking random values to do the math. I should also mention that my actual raster is something like 6000 by 3000. I'm pretty sure arcpy can handle the math of multiplication (line 41) and addition (line 45), but I have no idea why only the first iteration give a correct result. Is it a memory problem? Or do I need to clear the values after each iteration?

DanPatterson_Retired

Why are you using the Decimal module? You already have a numpy array, just continue doing your work with it then save it back out to arcmap if you really need to.

ft <SPAN class="operator token">=</SPAN> <SPAN class="punctuation token">{</SPAN><SPAN class="string token">'bool'</SPAN><SPAN class="punctuation token">:</SPAN> <SPAN class="keyword token">lambda</SPAN> x<SPAN class="punctuation token">:</SPAN> repr<SPAN class="punctuation token">(</SPAN>x<SPAN class="punctuation token">.</SPAN>astype<SPAN class="punctuation token">(</SPAN><SPAN class="string token">'int32'</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">,</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="string token">'float'</SPAN><SPAN class="punctuation token">:</SPAN> <SPAN class="string token">'{: 0.10f}'</SPAN><SPAN class="punctuation token">.</SPAN>format<SPAN class="punctuation token">}</SPAN>
np<SPAN class="punctuation token">.</SPAN>set_printoptions<SPAN class="punctuation token">(</SPAN>edgeitems<SPAN class="operator token">=</SPAN><SPAN class="number token">3</SPAN><SPAN class="punctuation token">,</SPAN> linewidth<SPAN class="operator token">=</SPAN><SPAN class="number token">100</SPAN><SPAN class="punctuation token">,</SPAN> precision<SPAN class="operator token">=</SPAN><SPAN class="number token">10</SPAN><SPAN class="punctuation token">,</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; suppress<SPAN class="operator token">=</SPAN><SPAN class="token boolean">True</SPAN><SPAN class="punctuation token">,</SPAN> threshold<SPAN class="operator token">=</SPAN><SPAN class="number token">100</SPAN><SPAN class="punctuation token">,</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; formatter<SPAN class="operator token">=</SPAN>ft<SPAN class="punctuation token">)</SPAN>
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b <SPAN class="operator token">=</SPAN> a<SPAN class="operator token">*</SPAN> <SPAN class="number token">0.2</SPAN>
a
array<SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">[</SPAN><SPAN class="punctuation token">[</SPAN> <SPAN class="number token">0.0000000000</SPAN><SPAN class="punctuation token">,</SPAN>&nbsp; <SPAN class="number token">1.0000000000</SPAN><SPAN class="punctuation token">,</SPAN>&nbsp; <SPAN class="number token">2.0000000000</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">,</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="punctuation token">[</SPAN> <SPAN class="number token">3.0000000000</SPAN><SPAN class="punctuation token">,</SPAN>&nbsp; <SPAN class="number token">4.0000000000</SPAN><SPAN class="punctuation token">,</SPAN>&nbsp; <SPAN class="number token">5.0000000000</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">,</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="punctuation token">[</SPAN> <SPAN class="number token">6.0000000000</SPAN><SPAN class="punctuation token">,</SPAN>&nbsp; <SPAN class="number token">7.0000000000</SPAN><SPAN class="punctuation token">,</SPAN>&nbsp; <SPAN class="number token">8.0000000000</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">)</SPAN>
b
array<SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">[</SPAN><SPAN class="punctuation token">[</SPAN> <SPAN class="number token">0.0000000000</SPAN><SPAN class="punctuation token">,</SPAN>&nbsp; <SPAN class="number token">0.2000000000</SPAN><SPAN class="punctuation token">,</SPAN>&nbsp; <SPAN class="number token">0.4000000000</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">,</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="punctuation token">[</SPAN> <SPAN class="number token">0.6000000000</SPAN><SPAN class="punctuation token">,</SPAN>&nbsp; <SPAN class="number token">0.8000000000</SPAN><SPAN class="punctuation token">,</SPAN>&nbsp; <SPAN class="number token">1.0000000000</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">,</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="punctuation token">[</SPAN> <SPAN class="number token">1.2000000000</SPAN><SPAN class="punctuation token">,</SPAN>&nbsp; <SPAN class="number token">1.4000000000</SPAN><SPAN class="punctuation token">,</SPAN>&nbsp; <SPAN class="number token">1.6000000000</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">)</SPAN>
<SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

The dtype is float64 which given your equations, I am not sure Decimal is needed given that its use can be circumvented in many situations by scaling and/or use of integer math.

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