Thiessen Polygon in arcgis-10.1

Question

I have a point shapefile of rain gauge stations (with data) which I want to use to create a Thiessen polygons over a basin/watershed (another shapefile). All the raingauge points are located within the spatial extents of the basin/watershed. I want my Thiessen polygon to cover the whole basin like this:

I used ArcToolbox/Analysis Tools/Proximity/Create Thiessen Polygons to create it and i got something like this:

I would like my polygons to cover the whole basin area.

Answer 1

You have to set your extents to another shapefile (or see other options). When you have your polygon tool open, you go into Advance (bottom RH corner) > Extents, you should find it.