comp.lang.idl-pvwave archive: archive » map_proj

Home » Public Forums » archive » map_proj_* help

Show: Today's Messages :: Show Polls :: Message Navigator
E-mail to friend

Re: map_proj_* help [message #66962 is a reply to message #66805]

Mon, 15 June 2009 14:46

David Fanning
Messages: 11724
Registered: August 2001

Senior Member

David Fanning writes:

> OK, I've written this up for general consumption.
> As always (probably the main reason I write these
> articles) I learned even more about the problem as
> I wrote it down. Anyway, the article shows you how to
> navigate both the GeoTiff and the PNG version of this
> image. They have to be done in slightly different ways
> due to unspoken "conventions".
>
> You can find the article here:
>
> http://www.dfanning.com/map_tips/iceshelf.html

Just to wrap this whole sorted tale up, I have asked
the good folks at NSIDC to please add the latitude
which is down from the map origin to the information
provided on their map image page. Without this piece
of information, it would be nearly impossible to navigate
the image successfully.

And I wanted to point out that IDL itself is a bit
confusing in this regard, in that the CENTER_LATITUDE
keyword, which normally identifies the latitude of
the map origin (at least it does in every map projection
I have ever worked with) does no such thing with polar
stereographic map projections. Instead, this keyword
identifies the true-scale latitude or standard latitude
(the terms are often used interchangeably). I've added
a bit more detail on this state of affairs in this article:

http://www.dfanning.com/map_tips/polarstereo.html

Cheers,

David

--
David Fanning, Ph.D.
Coyote's Guide to IDL Programming (www.dfanning.com)
Sepore ma de ni thui. ("Perhaps thou speakest truth.")

Report message to a moderator

[Message index]

		map_proj_* help By: mankoff on Sun, 07 June 2009 09:55
		Re: map_proj_* help By: R.G. Stockwell on Fri, 12 June 2009 13:38
		Re: map_proj_* help By: David Fanning on Fri, 12 June 2009 13:09
		Re: map_proj_* help By: mankoff on Fri, 12 June 2009 13:03
		Re: map_proj_* help By: David Fanning on Fri, 12 June 2009 12:49
		Re: map_proj_* help By: David Fanning on Fri, 12 June 2009 12:40
		Re: map_proj_* help By: David Fanning on Fri, 12 June 2009 12:32
		Re: map_proj_* help By: David Fanning on Sat, 13 June 2009 14:09
		Re: map_proj_* help By: David Fanning on Fri, 12 June 2009 11:51
		Re: map_proj_* help By: Bruce Bowler on Fri, 12 June 2009 11:48
		Re: map_proj_* help By: Bruce Bowler on Fri, 12 June 2009 11:43
		Re: map_proj_* help By: mankoff on Fri, 12 June 2009 11:28
		Re: map_proj_* help By: David Fanning on Fri, 12 June 2009 11:16
		Re: map_proj_* help By: David Fanning on Fri, 12 June 2009 08:47
		Re: map_proj_* help By: David Fanning on Mon, 15 June 2009 14:46

Previous Topic:	idl encoder/decoder of json
Next Topic:	Re: file_search: need work around for filenames with square brackets [ ]

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

] [

]

Current Time: Thu Oct 09 22:24:06 PDT 2025

Total time taken to generate the page: 1.60229 seconds