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Re: Polynomial warping of satellite images [message #12133]

Thu, 02 July 1998 00:00

Liam Gumley
Messages: 473
Registered: November 1994

Senior Member

William Connolley wrote:
> In article 5658@cdc.noaa.gov, Andy Loughe <afl@cdc.noaa.gov> writes:
>> What are the advantages of using POLYWARP or POLY_2D?
>> I thought MAP_IMAGE or MAP_PATCH were supposed to accomplish this task.
>
> I thought that map_image and map_patch assume that the image is pasted into
> a rectangle in lat-lon space, which has its sides EW and NS. Which is a major
> failing, since most satellite passes aren't arranged so conveniently. This was
> true last time I looked, and 5.1 doesn't seem to have improved it. Is use
> of polywarp supposed to get round that problem? I'd be interested if so.

You are correct. MAP_IMAGE and MAP_PATCH require data on a regular
lat/lon grid. Transforming irregularly gridded data to a regular grid is
pretty straightforward for small datasets, but it just isn't possible
(using TRIANGULATE and TRIGRID) to rectify large satellite images. I'm
sure it can be done with POLYWARP - I just need to find out exactly how
(the documentation is a bit obscure).

Cheers,
Liam.

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[Message index]

		Re: Polynomial warping of satellite images By: Liam Gumley on Thu, 02 July 1998 00:00
		Re: Polynomial warping of satellite images By: wmc on Wed, 01 July 1998 00:00
		Re: Polynomial warping of satellite images By: Andy Loughe on Tue, 30 June 1998 00:00

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