[GIS] Full list of objects not showing up after using Zonal Statistics as Table tool

arcgis-10.1arcgis-desktopspatial-analystzonal statistics

I am using the Zonal Statistics as Table tool in ArcMap 10.1 to compute the sum of raster cell values (brown scale in below image) in a given set of polygons (red in below image).

Image of what the data looks like

For an unknown reason, the output table is not including all the levels of the polygon file I am trying to get information about. I tried on a smaller set of polygons (as these polygons are buffers) and did not have the same problem. I have indeed asked the Zonal Statistics tool to ignore 'Nodata' (as shown in blue), so I am not sure why this is happening.
Suggestions?

Best Answer

The standard Zonal Statistics as Table tool does not support overlapping features. This may seem like a bug, but it's a symptom of the fact that Spatial Analyst rasterizes the any vector zone data before processing. Even without overlapping rasters, I tend to run Polygon to Raster myself ahead of time so I can better control cell sizes and snap rasters of the zone data.

Fortunately for you, there is an easy workaround! The Spatial Analyst Supplemental Tools, created by Esri, includes something called Zonal Statistics As Table 2. As described in the blog post:

The Zonal Statistics as Table 2 tool calculates statistics using the values of a raster within zones and reports the results to a table. This new version offers an improvement over the original Zonal Statistics as Table geoprocessing tool by fully handling overlapping polygons in feature zone input.

You should be able to use this toolbox to perform your desired analysis. I haven't used that toolbox in a year or two, so please report back if you have any compatibility issues with Arc 10.3 or 10.4.

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