Hope somebody can help me. I performed the interpolation (kriging) and got a geostatistical layer. Then I am using this method Predicting values for specified locations http://webhelp.esri.com/arcgisdesktop/9.3/index.cfm?TopicName=Predicting_values_for_specified_locati... When I set polygons as my specific locations I have the output with predicted values for each polygon in the attribute table. But when I select point locations at centers of the polygons, the predicted values are different. My question is: how ArcGIS predicts values for polygons? Any literature about this? Before I found this way, I was going to produce a grid with very small cells and then calculate average values of cells falling inside each polygon, but it is very time and memory consuming. But for using Predicting for locations I need to know exactly what is the method behind.
With the exception of areal interpolation in ArcGIS 10.1, geostatistical layers can only predict to points. If you supply a polygon feature class to predict to, it will predict the value at the polygon centroid.
To predict the value in a polygon, convert the geostatistical layer to raster (via GA Layer to Grid gp tool), then use Zonal Statistics as Table. You'll then need to join the table back to the polygons.
