This option only applies to Windgen stations at this time. Based upon a specific Windgen interpolation polygon map and a corresponding "reflected" Windgen stations map, if the lat/lon location falls within an "interpolated region" polygon, then the Windgen record is interpolated from data within three nearby Windgen stations. The lat/lon location is used for the "interpolated" station's location.
¤Note: that since Windgen generated data is dependent upon the statistical parameters in the station record, having an interpolated station that is even slightly different, e.g. even a few feet from another location will give a completely different sequence of weather (wind) data, even though, statitistically, the two interpolated stations would be essentially the same. Thus, care must be taken when selecting the use of the the "interpolated" mode alone. (See NRCS mode for how this issue is addressed there)
¤Note: Interpolation uses the NRCS station set, and will only interpolate off the NRCS station set. To determine which stations are being used, a user can load the Map Viewer and enable both the triangulation and reflection layers (pink lines are reflected stations, which will be given double weight in interpolation).