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Using arcpy to create slope surfaces

JoeBorgione

ArcGIS Pro 2.5

I have a number of .tif and ,img images that I need to convert into slope surfaces (as discussed here Display A Slope Raster ) and have been following the steps shown here: Slope—Help | Documentation .

However, I get one of two errors depending on where I send the slope.save() to. Here is my script:

<SPAN class="keyword token">import</SPAN> arcpy
<SPAN class="keyword token">from</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>sa <SPAN class="keyword token">import</SPAN> <SPAN class="operator token">*</SPAN>
<SPAN class="keyword token">import</SPAN> os
 
inDir <SPAN class="operator token">=</SPAN> r<SPAN class="string token">'C:\JoesStuff\SouthernImages'</SPAN>
<SPAN class="comment token">#outWS = r'C:\JoesStuff\SouthernImages\SlopeRasters' # to a folder</SPAN>
outWS <SPAN class="operator token">=</SPAN> r<SPAN class="string token">'C:\JoesStuff\SouthernImages\Rasters.gdb'</SPAN>  <SPAN class="comment token"># to a gdb</SPAN>

<SPAN class="keyword token">for</SPAN> i <SPAN class="keyword token">in</SPAN> os<SPAN class="punctuation token">.</SPAN>listdir<SPAN class="punctuation token">(</SPAN>inDir<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">:</SPAN> 
    <SPAN class="keyword token">if</SPAN> i<SPAN class="punctuation token">.</SPAN>endswith<SPAN class="punctuation token">(</SPAN><SPAN class="string token">'.tif'</SPAN><SPAN class="punctuation token">)</SPAN> <SPAN class="operator token">or</SPAN> i<SPAN class="punctuation token">.</SPAN>endswith<SPAN class="punctuation token">(</SPAN><SPAN class="string token">'.img'</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">:</SPAN>
        inRaster <SPAN class="operator token">=</SPAN> os<SPAN class="punctuation token">.</SPAN>path<SPAN class="punctuation token">.</SPAN>join<SPAN class="punctuation token">(</SPAN>inDir<SPAN class="punctuation token">,</SPAN>i<SPAN class="punctuation token">)</SPAN>
        outFile <SPAN class="operator token">=</SPAN> i<SPAN class="punctuation token">.</SPAN>split<SPAN class="punctuation token">(</SPAN><SPAN class="string token">'.'</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">[</SPAN><SPAN class="number token">0</SPAN><SPAN class="punctuation token">]</SPAN>
        outRaster <SPAN class="operator token">=</SPAN> f<SPAN class="string token">'{outWS}\{outFile}Slope'</SPAN>
        outMeasurement <SPAN class="operator token">=</SPAN> <SPAN class="string token">'PERCENT_RISE'</SPAN>
        zFactor <SPAN class="operator token">=</SPAN> <SPAN class="number token">1</SPAN>
        method <SPAN class="operator token">=</SPAN> <SPAN class="string token">'PLANAR'</SPAN>
        zUnit <SPAN class="operator token">=</SPAN> <SPAN class="string token">'METER'</SPAN>
    
    outSlope <SPAN class="operator token">=</SPAN> Slope<SPAN class="punctuation token">(</SPAN>inRaster<SPAN class="punctuation token">,</SPAN> outMeasurement<SPAN class="punctuation token">,</SPAN> zFactor<SPAN class="punctuation token">,</SPAN> method<SPAN class="punctuation token">,</SPAN> zUnit<SPAN class="punctuation token">)</SPAN>
    outSlope<SPAN class="punctuation token">.</SPAN>save<SPAN class="punctuation token">(</SPAN>outRaster<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>

with line 6 commented and line 7 active this error is returned:

RuntimeError: ERROR 010240: Could not save raster dataset to 
C:\JoesStuff\SouthernImages\Rasters.gdb\12TVK1276Slope with output format FGDBR.<SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

if I try to save the slope to a directory by executing line 6 with line 7 commented this error is returned

RuntimeError: ERROR 010240: Could not save raster dataset to 
C:\JoesStuff\SouthernImages\SlopeRasters\12TVK1276Slope with output format GRID.<SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

I know the slope surfaces are being created, because when I comment line 20, and replace it with a print statement, the loop runs just fine. I have run tool manually and it works just great on individual input .tif or .img.

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JoeBorgione

Thanks for the tip Dana! I vacillate between arcpy and straight up python through out my scripting: that list came from an os.listdir() I ran on the directory where I had stashed the originals....

Anonymous User

Hi Joe,

I checked out this thread and the script you created. I'm glad you were able to reach a solution.

I wanted to show you another way to script it, using arcpy.env.workspace, and a boolean variable.

Using arcpy.env.workspace, you don't need to code the full path to every image in your list.

Using a boolean variable (i.e. 'tifOut' and some 'if' logic), you only need to update the code in one place, if you wish to switch from TIF to fgdb.

Please reach out if you have questions.

Happy scripting!
Dana

<SPAN class="comment token"># ----------------------------------------------------#</SPAN>
<SPAN class="comment token"># Program: Loop through images and create Slope output</SPAN>
<SPAN class="comment token"># Save outputs as either TIF or FGDB raster</SPAN>
<SPAN class="comment token"># ----------------------------------------------------#</SPAN>

<SPAN class="comment token"># ----------------------------------------------------#</SPAN>
<SPAN class="comment token"># imports</SPAN>
<SPAN class="keyword token">import</SPAN> arcpy
<SPAN class="keyword token">from</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>sa <SPAN class="keyword token">import</SPAN> <SPAN class="operator token">*</SPAN>
<SPAN class="keyword token">import</SPAN> os
<SPAN class="comment token"># ----------------------------------------------------#</SPAN>

<SPAN class="comment token"># ----------------------------------------------------#</SPAN>
<SPAN class="comment token"># environments</SPAN>
arcpy<SPAN class="punctuation token">.</SPAN>env<SPAN class="punctuation token">.</SPAN>workspace <SPAN class="operator token">=</SPAN> r<SPAN class="string token">'C:\JoesStuff\SouthernImages'</SPAN>
<SPAN class="comment token"># ----------------------------------------------------#</SPAN>

<SPAN class="comment token"># ----------------------------------------------------#</SPAN>
<SPAN class="comment token"># variables: tifOut, fgdbOut, imageList</SPAN>
<SPAN class="comment token"># ----------------------------------------------------#</SPAN>
<SPAN class="comment token"># Set tifOut variable</SPAN>
<SPAN class="comment token"># when True: output to workspace as tif</SPAN>
<SPAN class="comment token"># when False: output to fgdbOut </SPAN>
tifOut <SPAN class="operator token">=</SPAN> <SPAN class="token boolean">False</SPAN>
fgdbOut <SPAN class="operator token">=</SPAN> <SPAN class="string token">'Rasters.gdb'</SPAN>

imageList <SPAN class="operator token">=</SPAN> <SPAN class="punctuation token">[</SPAN><SPAN class="string token">'12TVK1276.tif'</SPAN><SPAN class="punctuation token">,</SPAN>
 <SPAN class="string token">'12TVK1474.tif'</SPAN><SPAN class="punctuation token">,</SPAN>
 <SPAN class="string token">'12TVK1476.tif'</SPAN><SPAN class="punctuation token">,</SPAN>
 <SPAN class="string token">'C12TVK1674.tif'</SPAN><SPAN class="punctuation token">,</SPAN>
 <SPAN class="string token">'12TVK1676.tif'</SPAN><SPAN class="punctuation token">,</SPAN>
 <SPAN class="string token">'12TVK1874.tif'</SPAN><SPAN class="punctuation token">,</SPAN>
 <SPAN class="string token">'12TVK1876.tif'</SPAN><SPAN class="punctuation token">,</SPAN>
 <SPAN class="string token">'12TVK1877.tif'</SPAN><SPAN class="punctuation token">,</SPAN>
 <SPAN class="string token">'12TVK1976.tif'</SPAN><SPAN class="punctuation token">,</SPAN>
 <SPAN class="string token">'12TVK1977.tif'</SPAN><SPAN class="punctuation token">,</SPAN>
 <SPAN class="string token">'hh12TVK1200076000.img'</SPAN><SPAN class="punctuation token">,</SPAN>
 <SPAN class="string token">'hh12TVK1200078000.img'</SPAN><SPAN class="punctuation token">,</SPAN>
 <SPAN class="string token">'hh12TVK1400076000.img'</SPAN><SPAN class="punctuation token">,</SPAN>
 <SPAN class="string token">'hh12TVK1400078000.img'</SPAN><SPAN class="punctuation token">,</SPAN>
 <SPAN class="string token">'hh12TVK1600076000.img'</SPAN><SPAN class="punctuation token">,</SPAN>
 <SPAN class="string token">'hh12TVK1600078000.img'</SPAN><SPAN class="punctuation token">,</SPAN>
 <SPAN class="string token">'hh12TVK1800074000.img'</SPAN><SPAN class="punctuation token">,</SPAN>
 <SPAN class="string token">'hh12TVK1800076000.img'</SPAN><SPAN class="punctuation token">,</SPAN>
 <SPAN class="string token">'hh12TVK1800078000.img'</SPAN><SPAN class="punctuation token">]</SPAN>

<SPAN class="comment token"># ----------------------------------------------------#</SPAN>
<SPAN class="comment token"># Main:</SPAN>
<SPAN class="comment token"># 1. Loop through images</SPAN>
<SPAN class="comment token"># 2. Set up Slope parameters</SPAN>
<SPAN class="comment token">#    a) Check if tifOut is True or False</SPAN>
<SPAN class="comment token"># 3. Execute Slope tool</SPAN>
<SPAN class="comment token"># 4. Save output</SPAN>
<SPAN class="comment token"># ----------------------------------------------------#</SPAN>

<SPAN class="comment token"># 1. Loop through images</SPAN>
<SPAN class="keyword token">for</SPAN> image <SPAN class="keyword token">in</SPAN> imageList<SPAN class="punctuation token">:</SPAN>
    <SPAN class="comment token"># 2. Set up Slope parameters</SPAN>
    inRaster <SPAN class="operator token">=</SPAN> image
    outRaster <SPAN class="operator token">=</SPAN> <SPAN class="string token">'Slope'</SPAN> <SPAN class="operator token">+</SPAN> os<SPAN class="punctuation token">.</SPAN>path<SPAN class="punctuation token">.</SPAN>splitext<SPAN class="punctuation token">(</SPAN>image<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">[</SPAN><SPAN class="number token">0</SPAN><SPAN class="punctuation token">]</SPAN>

    <SPAN class="comment token"># a) Check if tifOut is True or False</SPAN>
    <SPAN class="comment token"># If tifOut is True, add extension</SPAN>
    <SPAN class="keyword token">if</SPAN> tifOut <SPAN class="operator token">==</SPAN> <SPAN class="token boolean">True</SPAN><SPAN class="punctuation token">:</SPAN>
        outRaster <SPAN class="operator token">=</SPAN> outRaster <SPAN class="operator token">+</SPAN> <SPAN class="string token">".tif"</SPAN>
    <SPAN class="comment token"># If tifOut is False, add fgdbOut</SPAN>
    <SPAN class="keyword token">else</SPAN><SPAN class="punctuation token">:</SPAN>  
        outRaster <SPAN class="operator token">=</SPAN> os<SPAN class="punctuation token">.</SPAN>path<SPAN class="punctuation token">.</SPAN>join<SPAN class="punctuation token">(</SPAN>fgdbOut<SPAN class="punctuation token">,</SPAN>outRaster<SPAN class="punctuation token">)</SPAN>
    
    outMeasurement <SPAN class="operator token">=</SPAN> <SPAN class="string token">'PERCENT_RISE'</SPAN>
    zFactor <SPAN class="operator token">=</SPAN> <SPAN class="number token">1</SPAN>
    method <SPAN class="operator token">=</SPAN> <SPAN class="string token">'PLANAR'</SPAN>
    zUnit <SPAN class="operator token">=</SPAN> <SPAN class="string token">'METER'</SPAN>
    <SPAN class="comment token"># 3. Execute Slope tool</SPAN>
    outSlope <SPAN class="operator token">=</SPAN> Slope<SPAN class="punctuation token">(</SPAN>inRaster<SPAN class="punctuation token">,</SPAN> outMeasurement<SPAN class="punctuation token">,</SPAN> zFactor<SPAN class="punctuation token">,</SPAN> method<SPAN class="punctuation token">,</SPAN> zUnit<SPAN class="punctuation token">)</SPAN>
    <SPAN class="comment token"># 4. Save output</SPAN>
    outSlope<SPAN class="punctuation token">.</SPAN>save<SPAN class="punctuation token">(</SPAN>outRaster<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>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</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

wait until you see a 4.1.1 version

JoeBorgione

Actually the laptop I'm using has spyder 3.3 on it since I just went with what ships with Pro 2.5; remember I'm home practicing good social distancing. My desktop back at the office has a spyder 3.3 env as well as spyder 4.0 env; I have some packages I use that would have downgraded the 4.0 env so now I have two. Sounds like I may have three once I'm back there.....

(you're not even gonna give me a hint?)

DanPatterson_Retired

In anticipation of your next question....

Then I suppose I shouldn't tell you what happens if you do the spyder 4.1 update and let you figure it out on your own

JoeBorgione

Okay: got it wired using both of your suggestions. Here's the final script

import arcpy
from arcpy.sa import *
import os
 
inDir = r'C:\JoesStuff\SouthernImages'
#outWS = r'C:\JoesStuff\SouthernImages\SlopeRasters' # to a folder
outWS = r'C:\JoesStuff\SouthernImages\Rasters.gdb'  # to a gdb


imageList = ['C:\\JoesStuff\\SouthernImages\\12TVK1276.tif',
 'C:\\JoesStuff\\SouthernImages\\12TVK1474.tif',
 'C:\\JoesStuff\\SouthernImages\\12TVK1476.tif',
 'C:\\JoesStuff\\SouthernImages\\12TVK1674.tif',
 'C:\\JoesStuff\\SouthernImages\\12TVK1676.tif',
 'C:\\JoesStuff\\SouthernImages\\12TVK1874.tif',
 'C:\\JoesStuff\\SouthernImages\\12TVK1876.tif',
 'C:\\JoesStuff\\SouthernImages\\12TVK1877.tif',
 'C:\\JoesStuff\\SouthernImages\\12TVK1976.tif',
 'C:\\JoesStuff\\SouthernImages\\12TVK1977.tif',
 'C:\\JoesStuff\\SouthernImages\\hh12TVK1200076000.img',
 'C:\\JoesStuff\\SouthernImages\\hh12TVK1200078000.img',
 'C:\\JoesStuff\\SouthernImages\\hh12TVK1400076000.img',
 'C:\\JoesStuff\\SouthernImages\\hh12TVK1400078000.img',
 'C:\\JoesStuff\\SouthernImages\\hh12TVK1600076000.img',
 'C:\\JoesStuff\\SouthernImages\\hh12TVK1600078000.img',
 'C:\\JoesStuff\\SouthernImages\\hh12TVK1800074000.img',
 'C:\\JoesStuff\\SouthernImages\\hh12TVK1800076000.img',
 'C:\\JoesStuff\\SouthernImages\\hh12TVK1800078000.img']


for i in enumerate(imageList): 
    inRaster = i[1]
    outName = f'Slope{i[0]}'  # f'Slope{i[0]}.tif'
    outRaster = f'{outWS}\{outName}'
    outMeasurement = 'PERCENT_RISE'
    zFactor = 1
    method = 'PLANAR'
    zUnit = 'METER'
    
    outSlope = Slope(inRaster, outMeasurement, zFactor, method, zUnit)
    outSlope.save(outRaster)<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>

I read an article earlier today suggesting enumerate() instead of range() in a for loop and went that route. Line 33

can go to an FGDB grid or TIF image depending on which line (6 or 7) is executed.

So in essence you both answered my question so I'll let you duke it out for bragging rights and just assign it 'Assumed Answered'...

JoeBorgione

Let me give that a try: slope.save(C:\path\to\DansSlope.tif), right?

DanPatterson_Retired

*tif is all I use for rasters, I don't even use esri grids anymore and the last thing I would want is for my work to be tied up in a fgdb if I had to use it somewhere else that can't read fgdb . With *.tif, I can look at in image software, process it in python, numpy etc. even esri recommends tif (buried in the help,).

symbology is after the fact.

JoeBorgione

As mentioned, when I run the tool manually, all is good:

Note the values used by default in the symbology: I'm not sure what was going on when I created the slope surfaces mentioned in the other thread getting the values that were nonsensical (to me). These values are what I expect:

Looks like DansSlope is a good ol' FGDBR type, right?

DanPatterson_Retired

the other thread isn't closed

*.tif is the preferred raster format, so the destination of the raster should be a compliant folder path

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