New Post: IDW Interpolation

I'm trying to interpolate rain data from some stations. I have the accumulated value for each point and need to create a grid for a specific area.
As the goal of my project is to create a plugin for MapWindow, I'm using the "Imports MapWinGeoProc.Interpolation" declaration to import the interpolation procedures.

The IDW method is an option, but the simple code below is not working (using Visual Studio 2010 and MapWindow 4.8.8):

Imports MapWinGeoProc.Interpolation
....
IDW("c:\temp\points.shp", 3, "c:\temp\idw_pnts.asc")

The folowing error is generated in the debug:
"startIndex cannot be larger than length of string".

Points.shp is point shapefile that has the rain data in the field of index 3.


Any help? Is IDW interpolation or MapWinGeoProc library no longer supported?