converting projections

[Gerald I. Evenden]

>Date: Fri, 7 Jan 94 10:19:47 PST
>From: qi at cdrgsun.UCSD.EDU (ye qi)
>Subject: converting projections
>
>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.
>
>===================================
>Ye Qi
>Scripps Institution of Oceanography
>Email: qi at cdrgsun.ucsd.edu
>===================================

Is sounds like a simple case of inverse projection of the Mercator
coordinates into "geographic" (lat/lon) coordinates.  There is another
projection called "Plate Carree" but that is not synonmous with
geographic coordinates.

There are several programs which will handle this process but you
sound like you are not familiar with this general process.  Perhaps
you can email me directly with some specifics of your problem.

Gerald (Jerry) I. Evenden   Internet: gie at charon.er.usgs.gov
voice: (508)563-6766          Postal: P.O. Box 1027
  fax: (508)457-2310                  N.Falmouth, MA 02556-1027