Error: Operation Failed [using Zonal Statistics]
When running the Zonal Statistics function in Spatial Analyst, the following error message may occur:
The zone raster dataset might not have an attribute table. Zonal Statistics requires the zone dataset contain an attribute table.
Solution or Workaround
To create an Attribute Table for the zone dataset, add the layer to the Raster Calculator, [Inlayer], and evaluate.
This procedure creates a temporary raster with the same values as the original layer and with an attribute table. Using this output raster as the zone dataset produces an output from the Zonal Statistics function.
It is recommended that integer rasters have a permanent attribute table.
Under certain conditions, the attribute table will not be automatically generated when an operation creates a Grid raster.
For more details on these conditions, and instructions on how to force the creation of the attribute table, see:
<a href='http://support.esri.com/en/knowledgebase/techarticles/detail/27056' target='_blank'>How To: Create a VAT</a>