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I have a raster image (.tif) that is multi bands (35 band), floating point data type that does not have attribute table, and a grid shapefile of 107 polygon created by the fishnet function in ArcGIS. Now, I need to overlay them to get the mean value of each polygon of that grid from underlying raster image values.

How can I do that using ArcGIS or ENVI?

I tried to use zonal statistics (tabulate) but nothing would be computed as there is no attribute table for the image!

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    Please indicate what software you have available, any sensible answer depends on that. Also please indicate if you have any scripting experience (or desire to learn).
    – Michael Stimson
    Feb 6, 2015 at 0:59
  • I'm thinking that your "grid shapefile of 107 polygon" may perhaps be the output of a vector grid creation process by either ArcGIS for Desktop or QGIS or ...?
    – PolyGeo ♦
    Feb 6, 2015 at 1:27
  • is it clearer now after editing?
    – Nour
    Feb 6, 2015 at 10:37

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You do not need vat's for your 35 band stack. It sounds like the problem is that your zonal raster does not have an attribute table. I would check what bit type the zonal raster is. If it floating point you cannot build a vat and will need to recreate it.

Once you have ascertained that the zonal raster is not float, you can build a vat for it using the ArcGIS Build Raster Attribute Table tool.

I am not sure if the zonal functions in ArcGIS will operate on a raster stack. If not you will need to bring in one raster at a time. When adding data you can double click on a raster and it will display the bands in the stack and you can then add a single raster from the stack.

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