IDW Interpolation

PatrickWard

I am trying to create a raster that interpolates weather station rainfall readings (point data) over areas in which there are no weather stations.  When I use the IDW tool, there is an interpolation over the area defined by the northernmost, southernmost, easternmost, and westernmost weather stations, but I would actually like to extend the interpolation beyond these boundaries so that it can later be spatially joined with a polygon shapefile.  Does anyone know if/how this can be accomplished?

DanPatterson_Retired

It would be horrendously easy to simply set the analysis extent to a larger size to extend to your desired boundary, but I would suggest that the results would be meaningless or misleading at best unless you know that such an interpolation would generate valid results beyond the bounds of the input data.   Also, why have you picked IDW as the interpolator given the other options available to you.  Perhaps there is a problem design issue that you could address before settling in on a means to fill in the gaps between stations.