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Re: Confusions with map_image! [message #66970 is a reply to message #66858]

Fri, 12 June 2009 17:49

jameskuyper
Messages: 79
Registered: October 2007

Member

David Fanning wrote:
...
> MAP_IMAGE is really a *display* technique (and a
> poor one at that). It would probably be much better
> to fit a map coordinate system to your image, rather
> than fit the image to your coordinate system.

It sounds like the original data he's using are MODIS L2 products, in
which case the the most appropriate coordinate system to use for any
given orbit's worth of data would be virtually any cylindrical
projection with it's axis tilted so that the "equator" of the projection
corresponds roughly to the ground path of the satellite (it can't be an
exact fit). However, he's interested in an entire day's worth of data
covering (incompletely) the entire globe. No single projection is going
to be a good fit for all of the orbits of an entire day's worth of data.
I think he's stuck with fitting his data to his coordinate system, and
not vice versa.

MODIS data, because of the high inclination of it's orbit, heavily
over-samples the polar regions. About the only thing he could do to
adapt his projection to the data is to choose one that exaggerates the
size of the polar regions; but that would only make sense if he's
actually interested in the polar regions.

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[Message index]

		Re: Confusions with map_image! By: hethomas on Fri, 12 June 2009 08:20
		Re: Confusions with map_image! By: David Fanning on Fri, 12 June 2009 08:05
		Re: Confusions with map_image! By: hethomas on Fri, 12 June 2009 07:48
		Re: Confusions with map_image! By: David Fanning on Fri, 12 June 2009 07:32
		Re: Confusions with map_image! By: hethomas on Fri, 12 June 2009 07:02
		Re: Confusions with map_image! By: David Fanning on Fri, 12 June 2009 06:39
		Re: Confusions with map_image! By: hethomas on Fri, 12 June 2009 06:24
		Re: Confusions with map_image! By: David Fanning on Fri, 12 June 2009 05:37
		Re: Confusions with map_image! By: jameskuyper on Fri, 12 June 2009 17:49

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