I am experiencing errors with Geospatial Modeling Environment (GME) that suddenly developed after things were working perfectly.
1. Description of software installed:
- ArcGIS 10.3.1 for Desktop and ArcGIS Service Pack: 0 (build 0); R version 3.3.2; Geospatial Modelling Environment (Version 0.7.4.0)
2. What I'm trying to do
- I am using the tool "isectpolyrst." My polygon file has 5718 rows with overlapping buffers. Buffer size is 90m around points. I am trying to extract Normalized Difference Vegetation Index raster data (NDVI; from MODIS) to each polygon. NDVI values range from -2000 to 9000.
- I do not get an error message. However, the values of the raster I am trying to extract do not match the output. See #3 below.
- The tool processes very, very quickly. The output value for each polygon is identical (mean = -1.797693e+308).
- These values are not correct (ie there is variation and the values do not match)
- The tricky part is the tool worked properly until a few weeks ago. I did not upgrade GIS, nor did I change the files at all.
3. What I've tried to trouble shoot:
- Double check projections are the same for polygon and raster data.
- Downloading NDVI files again. Perhaps they got corrupted?
- Scaling my data to 0-100 values (subtract by minimum value, divide by range, multiply by 100).
- Converting to different raster file type (TIFF, IMAGINE, GRID)
- Assigning attribute table to NDVI raster data (no luck)
- Try on different machines (all have Windows)
- Using the Zonal Stats as Table II in ArcMap. This is a finicky tool and I can never get it to work on >300 rows
I AM STUMPED!!! Does anyone have any ideas on how to proceed? This is an issue I've heard from other folks, but no one found a work around in GME.