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20041103: Grid interpolation and WMS

>From: "Rob Redmon" <address@hidden>
>Organization: NOAA
>Keywords: 200411031545.iA3Fj8vV029743

Hi Rob-

>Hi Don, I'm writing regarding our conversation about grid sampling
>and interpolation during the IDV workshop.  

The resampling in VisAD/IDV is done as follows:

The samples are organized in a topology, which may be
triangles (Irregular2D), squares (Gridded2D), tetrahedra
(Irregular3D) or cubes (Gridded3D). For target points
the system finds which topology element contains the
target. For nearest neighbor, it gets the values at the
vertex of that containing topology element closest to the
target point. For weighted average, its computes a
weighted average of all vertices of that containing
topology element, where the weights are bilinear in
2-D and trilinear in 3-D.

(from Bill Hibbard).

>I believe you mentioned
>something about an Australian (?) group that may be writing a related
>package and I'm definitely interested in learning more about that.  

Contact James Kelley (address@hidden) about his Barnes Analysis
code.  Tell him I sent you.  Eventually, we'll add that to the
IDV, but you might want to use it in it's raw form.

>You also mentioned forwarding me some WMS info.

From the Catalog Chooser, try the following URL:

http://globe.digitalearth.gov/viz-bin/wmt.cgi?REQUEST=GetCapabilities&VERSION=1.1

This will bring up an interface that allows you to select some 
images from the GLOBE project's WMS server.  This is really only
alpha code. Pick a field like Air Temperature->Maximum
Temperature (map doesn't do anything right now), then click
Add Source.  From the Data Selector, display the field as
a 3 Color (RGB) image.  It should display in the main window.

>Thanks again for a great workshop!

Thanks for attending and using the IDV.  Let us know if you have
more questions or suggestions.

Don
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