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.
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.