converting projections

ye qi qi at cdrgsun.UCSD.EDU
Fri Jan 7 21:03:31 EST 1994


Dear Dr. Evenden:

I am so glad I have finally got the expert.  In fact, I have just read your 63 
page user mannual on porj but still have no idea how to do it.

Here is my problem.  I have a series of data of the global vegetation index
propared by Kevin Gallo at NOAA/NESDIS.  The actual data coverage is within
75N-55S and 180W-180E and they are in Mercator projection.  I want to change
them to Lat/Lon, in order to match our other data sets.  So it is not just a 
matter of translating one type of coordinates to another, the values (a 
function of coordinates) must be changed as well.

My raster data in Mercator projection has 1038 rows and 2048 colums (for the 
whole earth) needs to be changed to another raster file with 1080 rows and 2160
colums, i.e. 10' x 10' lat/lon.  Each grid cell in the new file has to be 
assigned a value based on its area and the value(s) of its coresponding cell(s).

Several email message I received from the grassu-list suggested to use IDRISI
and arc/info.  I don't have arc/info.  I do have idrisi here but I prefer to 
work on my workstation because of the size of the data sets.  Any advice will
be greatly appreciated.

Thank you very much for your time.


Best regards,


===================================
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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