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Map_proj_forward.pro [message #90580]

Wed, 11 March 2015 15:34

xiaoxiaoxi
Messages: 1
Registered: March 2015

Junior Member

Hi Everyone,

I need to use map_proj_forward function in IDL but the problem is I couldn't find the source code or algorithm behind it anywhere online. Can anyone help me with this please?

Thanks!

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Re: Map_proj_forward.pro [message #90581 is a reply to message #90580]

Wed, 11 March 2015 15:55

David Fanning
Messages: 11724
Registered: August 2001

Senior Member

xiaoxiaoxi writes:

> I need to use map_proj_forward function in IDL but the problem is I couldn't find the source code or algorithm behind it anywhere online. Can anyone help me with this please?

The Map_Proj_**** routines use the US Geological Survey's General
Cartographic Transformation Package (GCTP) version 2 software. This was
state of the art map projection software in the 1980s and is still the
most professional and accurate map projection software available in IDL.
Most other software these days (including ENVI), use the PROJ4 software.

http://www.geography.hunter.cuny.edu/mp/software.html

For most map projections, the GCTP projection information is perfectly
adequate. I've always found the Map_Proj_Forward function to be
accurate.

Cheers,

David

--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.idlcoyote.com/
Sepore ma de ni thue. ("Perhaps thou speakest truth.")

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