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Re: Maps and interpolation w/ invalid data points [message #65958 is a reply to message #65956]

Mon, 30 March 2009 11:12

David Fanning
Messages: 11724
Registered: August 2001

Senior Member

mankoff writes:

> I'm having trouble with making smoothed maps with invalid data points.
> I'm able to produce maps with grayed invalid boxes when there is no
> smoothing (bilinear=0 in map_image). I'm able to produce interpolated
> images without getting the rainbows around the invalid points by using
> TRIANGULATE and TRIGRID.
>
> But I'm having trouble combining these two techniques.
>
> My input data is 72 by 44, so map_image replicates most of the data
> points when returning an array around 500 by 300. If /BILINEAR is set
> then I get rainbows around the invalid data points. If it is not set,
> and I run my triangulate & trigrid algorithm it doesn't have much
> effect due to the repetition of similar values due to the enlarged
> warped array. Setting MIN_VALUE and MISSING keywords to map_image
> doesn't help either.
>
> It seems like if I set the output size of the map to be tiny, so that
> map_image did not enlarge the array, then it would work. If producing
> postscript I could blow it up after and it would still look good. But
> this seems like a strange workaround.

I don't follow the reasoning here. Wouldn't you fix
the small 72 by 44 image with your Triangulate and Trigrid
method first, then warp this into your map space with Map_Image?

Cheers,

David

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

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[Message index]

		Re: Maps and interpolation w/ invalid data points By: David Fanning on Mon, 30 March 2009 11:49
		Re: Maps and interpolation w/ invalid data points By: mankoff on Mon, 30 March 2009 11:24
		Re: Maps and interpolation w/ invalid data points By: David Fanning on Mon, 30 March 2009 11:12

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