topic Re: Using arcpy to create slope surfaces in ArcGIS Spatial Analyst Questions

Using arcpy to create slope surfaces

JoeBorgione — Sat, 11 Dec 2021 10:11:46 GMT

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:

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

for i in os.listdir(inDir): 
    if i.endswith('.tif') or i.endswith('.img'):
        inRaster = os.path.join(inDir,i)
        outFile = i.split('.')[0]
        outRaster = f'{outWS}\{outFile}Slope'
        outMeasurement = 'PERCENT_RISE'
        zFactor = 1
        method = 'PLANAR'
        zUnit = 'METER'
    
    outSlope = Slope(inRaster, outMeasurement, zFactor, method, zUnit)
    outSlope.save(outRaster)‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

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.‍‍

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.‍‍

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.

Re: Using arcpy to create slope surfaces

DanPatterson_Retired — Thu, 19 Mar 2020 16:01:49 GMT

the other thread isn't closed

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

Re: Using arcpy to create slope surfaces

JoeBorgione — Thu, 19 Mar 2020 16:20:55 GMT

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?

Re: Using arcpy to create slope surfaces

DanPatterson_Retired — Thu, 19 Mar 2020 16:31:51 GMT

*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.

Re: Using arcpy to create slope surfaces

JoeBorgione — Thu, 19 Mar 2020 16:54:59 GMT

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

Re: Using arcpy to create slope surfaces

DanPatterson_Retired — Thu, 19 Mar 2020 17:00:34 GMT

the reason the "grid" format failed... you can't have esri grids begin with a number

Re: Using arcpy to create slope surfaces

SteveLynch — Thu, 19 Mar 2020 17:26:17 GMT

...and a "grid" name cannot exceed 13 characters.

Re: Using arcpy to create slope surfaces

JoeBorgione — Sat, 11 Dec 2021 10:11:48 GMT

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)‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

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'...

Re: Using arcpy to create slope surfaces

DanPatterson_Retired — Thu, 19 Mar 2020 18:48:56 GMT

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

Re: Using arcpy to create slope surfaces

JoeBorgione — Thu, 19 Mar 2020 18:58:48 GMT

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?)

Re: Using arcpy to create slope surfaces

DanPatterson_Retired — Thu, 19 Mar 2020 19:08:59 GMT

wait until you see a 4.1.1 version

Re: Using arcpy to create slope surfaces

Anonymous User — Sat, 11 Dec 2021 10:11:51 GMT

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

# ----------------------------------------------------#
# Program: Loop through images and create Slope output
# Save outputs as either TIF or FGDB raster
# ----------------------------------------------------#

# ----------------------------------------------------#
# imports
import arcpy
from arcpy.sa import *
import os
# ----------------------------------------------------#

# ----------------------------------------------------#
# environments
arcpy.env.workspace = r'C:\JoesStuff\SouthernImages'
# ----------------------------------------------------#

# ----------------------------------------------------#
# variables: tifOut, fgdbOut, imageList
# ----------------------------------------------------#
# Set tifOut variable
# when True: output to workspace as tif
# when False: output to fgdbOut 
tifOut = False
fgdbOut = 'Rasters.gdb'

imageList = ['12TVK1276.tif',
 '12TVK1474.tif',
 '12TVK1476.tif',
 'C12TVK1674.tif',
 '12TVK1676.tif',
 '12TVK1874.tif',
 '12TVK1876.tif',
 '12TVK1877.tif',
 '12TVK1976.tif',
 '12TVK1977.tif',
 'hh12TVK1200076000.img',
 'hh12TVK1200078000.img',
 'hh12TVK1400076000.img',
 'hh12TVK1400078000.img',
 'hh12TVK1600076000.img',
 'hh12TVK1600078000.img',
 'hh12TVK1800074000.img',
 'hh12TVK1800076000.img',
 'hh12TVK1800078000.img']

# ----------------------------------------------------#
# Main:
# 1. Loop through images
# 2. Set up Slope parameters
#    a) Check if tifOut is True or False
# 3. Execute Slope tool
# 4. Save output
# ----------------------------------------------------#

# 1. Loop through images
for image in imageList:
    # 2. Set up Slope parameters
    inRaster = image
    outRaster = 'Slope' + os.path.splitext(image)[0]

    # a) Check if tifOut is True or False
    # If tifOut is True, add extension
    if tifOut == True:
        outRaster = outRaster + ".tif"
    # If tifOut is False, add fgdbOut
    else:  
        outRaster = os.path.join(fgdbOut,outRaster)
    
    outMeasurement = 'PERCENT_RISE'
    zFactor = 1
    method = 'PLANAR'
    zUnit = 'METER'
    # 3. Execute Slope tool
    outSlope = Slope(inRaster, outMeasurement, zFactor, method, zUnit)
    # 4. Save output
    outSlope.save(outRaster)‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

Re: Using arcpy to create slope surfaces

JoeBorgione — Thu, 19 Mar 2020 22:24:59 GMT

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....