| Find out which area is covered in a map plot [message #70089] |
Fri, 12 March 2010 07:28  |
M. Suklitsch
Messages: 12
Registered: August 2008
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Junior Member |
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Hi, everybody!
Once in a while I run into the problem that I want to know which area
is actually displayed in a map projection.
For example, I have a Lambert projection displaying Europe and want to
plot wind barbs (using Coyote's WINDBARB routine) on top of it.
Problem is, the wind data is on a regular grid, which means that at
least in the corners (depending on the projection etc.) wind barbs
outside the map get plotted (see http://martin.suklitsch.at/img/1.1999051700.png
for an example of what I mean).
Therefore my question: is there a way to get the outermost lat/lon
values of the projection? If I had this information I could use
IDLgrROI to obtain the indices within my wind array which are located
within the map, set all others to NaN and plot the barbs as usual....
Any help is appreciated!
Best regards,
Martin
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| Re: Find out which area is covered in a map plot [message #70156 is a reply to message #70089] |
Tue, 16 March 2010 00:55  |
M. Suklitsch
Messages: 12
Registered: August 2008
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Junior Member |
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On Mar 15, 1:48 pm, David Fanning <n...@dfanning.com> wrote:
> David Fanning writes:
>> I don't think I said that. I think I said there
>> is no easy way, given that I don't know anything
>> at all about what command you used to set up the
>> map projection. It may be as simple as reading
>> the UV_BOX field of the event structure.
>
> Whoops! I mean "map structure", of course.
>
> Cheers,
>
> David
>
> --
> David Fanning, Ph.D.
> Fanning Software Consulting, Inc.
> Coyote's Guide to IDL Programming:http://www.dfanning.com/
> Sepore ma de ni thui. ("Perhaps thou speakest truth.")
OK, after having started two different replys I think I finally got
your point. But I have to think it through more thoroughly. Thanks
again!
Cheers,
Martin
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| Re: Find out which area is covered in a map plot [message #70160 is a reply to message #70089] |
Mon, 15 March 2010 05:48 |
David Fanning
Messages: 11724
Registered: August 2001
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Senior Member |
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David Fanning writes:
> I don't think I said that. I think I said there
> is no easy way, given that I don't know anything
> at all about what command you used to set up the
> map projection. It may be as simple as reading
> the UV_BOX field of the event structure.
Whoops! I mean "map structure", of course.
Cheers,
David
--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Sepore ma de ni thui. ("Perhaps thou speakest truth.")
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| Re: Find out which area is covered in a map plot [message #70161 is a reply to message #70089] |
Mon, 15 March 2010 05:45 |
David Fanning
Messages: 11724
Registered: August 2001
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Senior Member |
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M. Suklitsch writes:
> Thanks, David. Though I must admit it seems I have missed the spot
> where it says "using MAP_SET is bad". ;-)
>
> Anyway, there's obviously *no* easy way to get the information I need,
> that's the main message I get from your reply.
I don't think I said that. I think I said there
is no easy way, given that I don't know anything
at all about what command you used to set up the
map projection. It may be as simple as reading
the UV_BOX field of the event structure.
Cheers,
David
--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Sepore ma de ni thui. ("Perhaps thou speakest truth.")
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