Error calculating raster percentiles by polygon boundaries
Hello,
I've been trying the last 2 days to successfully run the python code kindly developed by Xander Bakker here. I used the script further down in that thread posted by 'Extractor' dated Jan 25th, 2019. I am using an elevation raster that has been converted to an integer type. The polygon layer is a feature class in a file geodatabase. Both the raster and feature class are in the same projected coordinate system.
The code runs great for awhile, then I get the error posted in the following screenshot:
Any ideas what is causing the error?
The only thought I had is that the polygon layer is watershed boundaries. Some of the polygons are nested within larger polygons. Could this be the issue? The code successfully processed 2 polygons where one was a subset of the other (polygons 3 and 4). Polygon 12 finished successfully - 12 is a small watershed nested inside polygon 13. The code failed on polygon 13. When viewing "ras13" it looks correct; however, no attribute table was created. I verified that "ras13" is an integer raster. Perhaps the behavior of crashing on nested polygons is unpredictable, or perhaps it is not the cause at all?
The only other thing that makes this polygon area different from the others is it is the largest of the set.
For "ras13":
Any help is appreciated,
Frances
Accepted Solutions
Hi Frances Biles ,
I downloaded the data and could replicate the error. First thing I did was loading the TIFF into the FileGeodatabase and using a separate File Geodatabase for the intermediate products (this normally give better results and working with the IN MEMORY workspace has some limitations with size). Still no luck.
Looking at the data, I notice two large polygons. To avoid limitations by size I separated the two larger polygons from the other smaller polygons and ran the process again using the smaller polygons. It still generated problems in the process. Looking at the temporal products, my ras13 was the last correctly processes raster, and the process halted at number 14. When I loaded the raster I noticed that the raster had no attribute table (hence the error you have seen).
What I also noticed is the large range of values for the DEM comparing ras13 and ras14. So, I used the raster calculator and divided the DEM by 10 explicitely converting the result to integer and tried again and this time it worked for both the small and the large rasters:
Please give it a try and let me know if this worked for you.
Hi Frances Biles ,
I downloaded the data and could replicate the error. First thing I did was loading the TIFF into the FileGeodatabase and using a separate File Geodatabase for the intermediate products (this normally give better results and working with the IN MEMORY workspace has some limitations with size). Still no luck.
Looking at the data, I notice two large polygons. To avoid limitations by size I separated the two larger polygons from the other smaller polygons and ran the process again using the smaller polygons. It still generated problems in the process. Looking at the temporal products, my ras13 was the last correctly processes raster, and the process halted at number 14. When I loaded the raster I noticed that the raster had no attribute table (hence the error you have seen).
What I also noticed is the large range of values for the DEM comparing ras13 and ras14. So, I used the raster calculator and divided the DEM by 10 explicitely converting the result to integer and tried again and this time it worked for both the small and the large rasters:
Please give it a try and let me know if this worked for you.
