converting projections

[ye qi]

Hello everyone:

Problem: converting projectiong MERCATER to LATITUDE/LONGITUDE.

Situation: I am working on NOAA/NGDC Experimental Calibrated Global Vegetation 
Index - biweekly data processed by Keven Gallo.  These data are in MERCATER 
projection and I want to convert them into LATITUDE/LONGITUDE (it has a more
professional name - ?? Caree ??, I can't remember).  I think there should be
a function for this conversion.  Could anyone give me quick guide on how to do
this or direct me to a right reference ?

Thank you.

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Ye Qi
Scripps Institution of Oceanography
University of California, San Diego
La Jolla, CA 92093-0220
Phone: (619)-534-4232
Fax:   (619)-534-0784
Email: qi at cdrgsun.ucsd.edu
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