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Calculates NDSSI from multispectral composite images from a folder

MohsinMeraj

I an new to arcpy and python. I have been trying to calculate NDSSI from 100 composite raster images from a folder using python script. Any how i tried my luck using a script but its not working. Taking list of rasters from one workspace and calculate NDSSI and store results in .tif format in another folder.

import arcpy, string
from arcpy import envfrom arcpy.sa import*
arcpy.CheckOutExtension("spatial")
env.workspace = r'E:\Landsat All Images\Processing\LT5\Composite'
outws = r'E:\Landsat All Images\Processing\LT5\NDSSI'
rasters = arcpy.ListRasters("*.tif")
for raster in rasters:
<SPAN class="" style="color: #2b91af; border: 0px; font-size: 13px;">Blue</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;">=</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;"> raster </SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;">+</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="color: #7d2727; border: 0px; font-size: 13px;">"\Band_1"</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;">NIR </SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;">=</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;"> raster </SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;">+</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="color: #7d2727; border: 0px; font-size: 13px;">"\Band_4"</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;"></SPAN><SPAN class="" style="color: #2b91af; border: 0px; font-size: 13px;">Num</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;">=</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;"> arcpy</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;">.</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;">sa</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;">.</SPAN><SPAN class="" style="color: #2b91af; border: 0px; font-size: 13px;">Float</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;">(</SPAN><SPAN class="" style="color: #2b91af; border: 0px; font-size: 13px;">Raster</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;">(</SPAN><SPAN class="" style="color: #2b91af; border: 0px; font-size: 13px;">Blue</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;">)</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;">-</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="color: #2b91af; border: 0px; font-size: 13px;">Raster</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;">(</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;">NIR</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;">))</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;"></SPAN><SPAN class="" style="color: #2b91af; border: 0px; font-size: 13px;">Denom</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;">=</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;"> arcpy</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;">.</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;">sa</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;">.</SPAN><SPAN class="" style="color: #2b91af; border: 0px; font-size: 13px;">Float</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;">(</SPAN><SPAN class="" style="color: #2b91af; border: 0px; font-size: 13px;">Raster</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;">(</SPAN><SPAN class="" style="color: #2b91af; border: 0px; font-size: 13px;">Blue</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;">)</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;">+</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="color: #2b91af; border: 0px; font-size: 13px;">Raster</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;">(</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;">NIR</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;">))</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;">NIR_eq </SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;">=</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;"> arcpy</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;">.</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;">sa</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;">.</SPAN><SPAN class="" style="color: #2b91af; border: 0px; font-size: 13px;">Divide</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;">(</SPAN><SPAN class="" style="color: #2b91af; border: 0px; font-size: 13px;">Num</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;">,</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="color: #2b91af; border: 0px; font-size: 13px;">Denom</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;">)</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;"> NIR_eq</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;">.</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;">save</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;">(</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;">outws</SPAN><SPAN class="" style="color: #303336; border: 0px; font-size: 13px;">)
<SPAN style="color: #242729; background-color: #ffffff;">print "Processing complete"</SPAN></SPAN>

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Accepted answers

XanderBakker

I just executed the code below and it worked for me:

<SPAN class="comment token"># Calculates NDVI from multispectral imagery</SPAN>
<SPAN class="keyword token">import</SPAN> arcpy
<SPAN class="keyword token">import</SPAN> os

<SPAN class="keyword token">from</SPAN> arcpy <SPAN class="keyword token">import</SPAN> env
arcpy<SPAN class="punctuation token">.</SPAN>CheckOutExtension<SPAN class="punctuation token">(</SPAN><SPAN class="string token">"Spatial"</SPAN><SPAN class="punctuation token">)</SPAN>
arcpy<SPAN class="punctuation token">.</SPAN>env<SPAN class="punctuation token">.</SPAN>overwriteOutput <SPAN class="operator token">=</SPAN> <SPAN class="token boolean">True</SPAN>

<SPAN class="comment token"># env.workspace = r'E:\Landsat All Images\Processing\LT5\Composite'</SPAN>
inws <SPAN class="operator token">=</SPAN> r<SPAN class="string token">'C:\Esri EPM\Drone2Map\EPM\products\2D\ortho_tiles'</SPAN>
outws <SPAN class="operator token">=</SPAN> r<SPAN class="string token">'C:\Esri EPM\Drone2Map\EPM\products\2D'</SPAN>
env<SPAN class="punctuation token">.</SPAN>workspace <SPAN class="operator token">=</SPAN> inws

rasters <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>ListRasters<SPAN class="punctuation token">(</SPAN><SPAN class="string token">"*.tif"</SPAN><SPAN class="punctuation token">)</SPAN>
<SPAN class="keyword token">for</SPAN> raster <SPAN class="keyword token">in</SPAN> rasters<SPAN class="punctuation token">:</SPAN>
&nbsp;&nbsp;&nbsp; <SPAN class="comment token"># You may need to change the band combinations.</SPAN>
&nbsp;&nbsp;&nbsp; <SPAN class="comment token"># This is for 4-band NAIP imagery or Landsat TM.</SPAN>
&nbsp;&nbsp;&nbsp; Blue <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>Raster<SPAN class="punctuation token">(</SPAN>os<SPAN class="punctuation token">.</SPAN>path<SPAN class="punctuation token">.</SPAN>join<SPAN class="punctuation token">(</SPAN>inws<SPAN class="punctuation token">,</SPAN> raster <SPAN class="operator token">+</SPAN> <SPAN class="string token">"\Band_1"</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">)</SPAN>
&nbsp;&nbsp;&nbsp; NIR <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>Raster<SPAN class="punctuation token">(</SPAN>os<SPAN class="punctuation token">.</SPAN>path<SPAN class="punctuation token">.</SPAN>join<SPAN class="punctuation token">(</SPAN>inws<SPAN class="punctuation token">,</SPAN> raster <SPAN class="operator token">+</SPAN> <SPAN class="string token">"\Band_4"</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">)</SPAN>

&nbsp;&nbsp;&nbsp; NIR_eq <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>sa<SPAN class="punctuation token">.</SPAN>Float<SPAN class="punctuation token">(</SPAN>Blue <SPAN class="operator token">-</SPAN> NIR<SPAN class="punctuation token">)</SPAN> <SPAN class="operator token">/</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>sa<SPAN class="punctuation token">.</SPAN>Float<SPAN class="punctuation token">(</SPAN>Blue <SPAN class="operator token">+</SPAN> NIR<SPAN class="punctuation token">)</SPAN>
&nbsp;&nbsp;&nbsp; out_name <SPAN class="operator token">=</SPAN> raster<SPAN class="punctuation token">.</SPAN>lower<SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">.</SPAN>replace<SPAN class="punctuation token">(</SPAN><SPAN class="string token">'.tif'</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="string token">'_NDVI.tif'</SPAN><SPAN class="punctuation token">)</SPAN>
&nbsp;&nbsp;&nbsp; out_ras <SPAN class="operator token">=</SPAN> os<SPAN class="punctuation token">.</SPAN>path<SPAN class="punctuation token">.</SPAN>join<SPAN class="punctuation token">(</SPAN>outws<SPAN class="punctuation token">,</SPAN> out_name<SPAN class="punctuation token">)</SPAN>
&nbsp;&nbsp;&nbsp; NIR_eq<SPAN class="punctuation token">.</SPAN>save<SPAN class="punctuation token">(</SPAN>out_ras<SPAN class="punctuation token">)</SPAN>

<SPAN class="keyword token">print</SPAN> <SPAN class="string token">"Processing complete"</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>

All comments

Luke_Pinner

Please never just say "it's not working". You are much more likely to get an answer by specifying what should happen and what actually happens, i.e does your script actually run at all, does it output the wrong result, does it output nothing, does it crash with an exception, what was the exception message, does python crash, does any smoke come out of your pc, does your pc vanish in a fiery explosion? Etc...

DanPatterson_Retired

You will need to format your code using the appropriate syntax highlighter.... It won't run as shown and impossible to dissect any errors that may be due to code structure or format.... have a look at

/blogs/dan_patterson/2016/08/14/script-formatting

MohsinMeraj

Thank You Dan for Guidance....I am beginner in programming. Here is code with using online syntax highlighter.

<SPAN class="comment token"># Calculates NDVI from multispectral imagery</SPAN>

<SPAN class="keyword token">import</SPAN> arcpy<SPAN class="punctuation token">,</SPAN> string

<SPAN class="keyword token">from</SPAN> arcpy <SPAN class="keyword token">import</SPAN> env
<SPAN class="keyword token">from</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>sa <SPAN class="keyword token">import</SPAN><SPAN class="operator token">*</SPAN>

arcpy<SPAN class="punctuation token">.</SPAN>CheckOutExtension<SPAN class="punctuation token">(</SPAN><SPAN class="string token">"spatial"</SPAN><SPAN class="punctuation token">)</SPAN>

env<SPAN class="punctuation token">.</SPAN>workspace <SPAN class="operator token">=</SPAN> r<SPAN class="string token">'E:\Landsat All Images\Processing\LT5\Composite'</SPAN>

outws <SPAN class="operator token">=</SPAN> r<SPAN class="string token">'E:\Landsat All Images\Processing\LT5\NDSSI'</SPAN>

rasters <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>ListRasters<SPAN class="punctuation token">(</SPAN><SPAN class="string token">"*.tif"</SPAN><SPAN class="punctuation token">)</SPAN>


<SPAN class="keyword token">for</SPAN> raster <SPAN class="keyword token">in</SPAN> rasters<SPAN class="punctuation token">:</SPAN>

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<SPAN class="comment token"># You may need to change the band combinations.&nbsp; </SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<SPAN class="comment token"># This is for 4-band NAIP imagery or Landsat TM.</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Blue <SPAN class="operator token">=</SPAN> raster <SPAN class="operator token">+</SPAN> <SPAN class="string token">"\Band_1"</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;NIR <SPAN class="operator token">=</SPAN> raster <SPAN class="operator token">+</SPAN> <SPAN class="string token">"\Band_4"</SPAN>

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Blue_out <SPAN class="operator token">=</SPAN> <SPAN class="string token">"Blue.tif"</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;NIR_out <SPAN class="operator token">=</SPAN> <SPAN class="string token">"NIR.tif"</SPAN>

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;arcpy<SPAN class="punctuation token">.</SPAN>CopyRaster_management<SPAN class="punctuation token">(</SPAN>Blue<SPAN class="punctuation token">,</SPAN>Blue_out<SPAN class="punctuation token">)</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;arcpy<SPAN class="punctuation token">.</SPAN>CopyRaster_management<SPAN class="punctuation token">(</SPAN>NIR<SPAN class="punctuation token">,</SPAN> NIR_out<SPAN class="punctuation token">)</SPAN>

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Num <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>sa<SPAN class="punctuation token">.</SPAN>Float<SPAN class="punctuation token">(</SPAN>Raster<SPAN class="punctuation token">(</SPAN>Blue<SPAN class="punctuation token">)</SPAN> <SPAN class="operator token">-</SPAN> Raster<SPAN class="punctuation token">(</SPAN>NIR<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">)</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Denom <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>sa<SPAN class="punctuation token">.</SPAN>Float<SPAN class="punctuation token">(</SPAN>Raster<SPAN class="punctuation token">(</SPAN>Blue<SPAN class="punctuation token">)</SPAN> <SPAN class="operator token">+</SPAN> Raster<SPAN class="punctuation token">(</SPAN>NIR<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">)</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;NIR_eq <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>sa<SPAN class="punctuation token">.</SPAN>Divide<SPAN class="punctuation token">(</SPAN>Num<SPAN class="punctuation token">,</SPAN> Denom<SPAN class="punctuation token">)</SPAN>

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;NIR_eq<SPAN class="punctuation token">.</SPAN>save<SPAN class="punctuation token">(</SPAN>outws<SPAN class="punctuation token">)</SPAN>
<SPAN class="keyword token">print</SPAN> <SPAN class="string token">"Processing complete"</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>

DanPatterson_Retired

If memory serves, you will have to specify the filename and not just the environment workspace as in this helpfile example Raster—Help | ArcGIS Desktop

Perhaps NIR_eq.save(outws+"/output.tif"

XanderBakker

Another thing to keep in mind, and what will probably create problems, is that fact that you save the Blue and NIR for each TIF to the same output name (in you input folder). Since you have not specified the "arcpy.env.overwriteOutput = True" it will produce an error for the second raster in the list.

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