Error When Trying to Run Slope Analysis Script

Question

I have written a script which is supposed to loop through all the rasters in a folder and perform a slope analysis on each raster and save the results in another folder.

I keep getting the following error:

< type 'exceptions.RuntimeError'>: ERROR 000875: Output raster: C:\Slope_Outputs\burd_25m_dem_slope's workspace is an invalid output workspace.

Here's my code:

class LicenseError(Exception):
 pass
# Set desktop license used to ArcView
#
import arcview
import arcpy
from arcpy import env
try:
 if arcpy.CheckExtension("Spatial") == "Available":
 arcpy.CheckOutExtension("Spatial")
 else:
 # Raise a custom exception
 raise LicenseError
except LicenseError:
 arcpy.AddMessage("Spatial Analyst license is unavailable")
except:
 print arcpy.GetMessages(2)
from arcpy.sa import *
originLocation = arcpy.GetParameterAsText(0)
slopeMeasurement = arcpy.GetParameterAsText(1)
destinationLocation = arcpy.GetParameterAsText(2)
arcpy.env.workspace = originLocation
rasterList = arcpy.ListRasters("*")
for raster in rasterList:
 finalDestination = destinationLocation+"\\"+raster+"_slope"
 arcpy.AddMessage(finalDestination)
 outSlope=arcpy.sa.Slope(raster, slopeMeasurement)
 arcpy.AddMessage(outSlope)
 outSlope.save(finalDestination)

I'm not really sure why I'm getting this error.

Any ideas?

Answer 1

I have found on this page that the maximum raster name length is 13 characters. I have modified my code to take the first 7 characters of the input raster name and add "_slope" at the end of it.

This works for now, but I think I will modify my code to write to a different file format instead of ESRI GRID or possibly a geodatabase instead.

• Emi: someone told me before that, the file name length should be 8, 11 or 13. He was not sure. 11 length worked for me. So, I told you to keep the name length less or equal 11. thanks for sharing the link :)
• Mike T: How about adding "_slope.tif" at the end? GeoTIFFs are fantastic, with no funny name length limitations.

Answer 2

try changing the workspace name to this C:\Slope_Outputs\burd_25m_dem_slopes. I think the problem might be that you are using unsupported characters in your workspace name. Maybe this post for ESRI will be helpful

• Fezter: There are no unsupported characters in the workspace name. The apostrophe after 'slope' was added by ArcGIS in displaying the error.

Answer 3

I am not sure about it. But Try those:

1. Try change the drive.
2. Try keep the raster name length less than or equal 11.

Answer 4

Perhaps the "\" is causing problems. Try the following:

import os # add this in with your other imports at top of code
finalDestination = destinationLocation + os.sep + raster + "_slope"