topic Re: Zonal Statistics - too many values? in ArcGIS Spatial Analyst Questions

Zonal Statistics - too many values?

JamesHook — Tue, 13 Sep 2011 14:29:44 GMT

I have a large polygon layer representing a few thousand fields, and raster layer with 3 land cover classes. I would like to summarize each field with a single land cover class, and the only tool I can think of to accomplish this is Zonal Statistics.

Problem is, when I try to run Zonal Statistics, I get ERROR 999999, "Too many unique values". What are the limitations on this tool, and is there a better way to perform this summary?

Re: Zonal Statistics - too many values?

JeffreySwain — Wed, 14 Sep 2011 11:34:34 GMT

You may be running into the limit of unique values in a raster. Go to the Customize > ArcMap Options > Raster Dataset. Adjust the 'Maximum number of unique values to render.' The default setting is to limit the processing time, so any adjustment up will increase the processing time.

Re: Zonal Statistics - too many values?

JamesHook — Wed, 14 Sep 2011 18:26:36 GMT

Thanks!

For others who may be interested in a solution, it also worked to reduce the number of zones in the zone feature class. Apparently this is a combination of value raster and zone layer size.