Take the 2-minute tour ×
Geographic Information Systems Stack Exchange is a question and answer site for cartographers, geographers and GIS professionals. It's 100% free, no registration required.

I have a single band raster image of 30m by 30m resolution. I have already created a polygon fishnet (grid) of 300m by 300m with point labels over that. How can I extract the mean pixel value of the raster image overlaying each feature in the fishnet grid? Is it possible with Arcgis? Please inform me.

share|improve this question
add comment

2 Answers

If you have the Spatial Analyst extension, you can use the Zonal Statistics tool with the raster as the value raster, the fishnet feature class as the zones, and the MEAN statistic option. The output will be a raster, where the value of each cell within a given zone will be the mean of all cells in that zone from the input raster.

Another option (which also requires Spatial Analyst) is using the Raster to Point tool, which will create a point for every single cell in the input raster. You will then be able to use the Spatial Join tool to create a new feature class with features identical to the fishnet polygons, but which will have an attribute value of the mean (or some other statistic) of all the points that fall within each polygon. Make sure your join operation is on-to-one and to set the match rule as "mean" for the attribute you're interested in.

share|improve this answer
add comment

nmpeterson - your answer works but I belive that using "Raster to Point" tool still requires Spatial Analyst.

A free workaround for Spatial Analyst's "zonal statistics" in ArcGIS 9.3 would be to download a very similar "zonal statistics" that you can get as part of Hawths Analysis Tools.

share|improve this answer
    
You're right, Raster to Point does also require Spatial Analyst. I just got thrown off because it's in a different toolbox. –  nmpeterson Nov 18 '11 at 20:09
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.