basemap.transform_scalar usage

basemap folks,

   I'm trying to understand how the transform_scalar function works. What are the units of the native projection grid and how are they determined? I'm trying to scale a scalar data field and overlay it on the map. Does the location of the origin matter when I do this? To be clear here's what I'm trying to do.

1) I have a Numeric array with a scalar field
2) I want to overlay this onto a map projection
3) The data is slightly larger than the map area (in terms of latitude and longitude)
4) From the examples it seams like transform_scalar and then imshow can be used to show the data
5) I can't seem to use transform_scalar properly

Thanks is advance,



Brian Donovan
Research Assistant
ERC for Collaborative Adaptive Sensing of the Atmosphere
University of Massachusetts
AIM: donovanatmirsl
Skype: bcdonovan