RE: [OpenMap Users] Extending to read from DODS / NetCDF

From: Keith Alphonso <kalphonso_at_diamonddata.com>
Date: Tue, 24 Aug 2004 08:21:21 -0500

We have a NetCDF based layer that we have created, here's how I did it.

If the projection is LLXY, I convert my NetCDF data to integer color values
then create an OMGrid using SimpleColorGenerator to render that grid. This,
however, is not projectable and only works for LLXY projection, but is a lot
faster than the alternative (below).

If the projection is something else I use the NetCDF grid to create an
OMRect for each data point, converting the data point to a color value to
color the rectangle. This works fairly well, but is obviously slow.


-----Original Message-----
From: Tennessee James Leeuwenburg [mailto:tjl_at_bom.gov.au]
Sent: Monday, August 23, 2004 7:30 PM
To: openmap-users_at_bbn.com
Subject: [OpenMap Users] Extending to read from DODS / NetCDF


Hi all,

I am currently using VisAD to render my data, but want to take OpenMap
for a spin also. This means extending Layer and writing DODSLayer or
NetCDFLayer. But I don't really understand how extending layer actually
does the trick, which also results in my not really understand how to go
about extending layer.

What I know how to do is to get the array of floats that represents my
data samples, and munge them into whatever form necessary - be that a 3d
array, or objects, whatever, I can slice and dice to the appropriate
data representation. What I don't understand how to do is to create the
requisite objects inside OpenMap. The FAQ says, "Once you have that, you
can create a list of OMGraphics that OpenMap will place on the map". Is
there an easy way to go from my data arrays to the OMGraphics list? I
have gridded data which I would like to represent as either contour
lines or color-shading, and point data which I would like to represent
as point measurements.

Anyway, I know I don't have the most perfect grasp of the openmap
system, but I'm hoping the user community won't mind some newbie questions!

Cheers,
-T
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Received on Tue Aug 24 2004 - 09:22:33 EDT

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