Re: [OpenMap Users] VPF data coverage

From: Don Dietrick <dietrick_at_bbn.com>
Date: Fri, 9 Jun 2006 10:10:26 -0400

Hi Thomas,

On Jun 1, 2006, at 2:07 PM, Thomas Coffin wrote:

>
> Hi,
>
> We are working with Vmap data and we wondered if it was possible to
> know
> within Openmap which area covers a given vmap data directory. We
> would like
> to display on a projection set at a world or continental scale
> which areas
> ar covered or not by the vmap data sets entered by the user. Ideally
> something like a different color for each pixel on the map,
> depending on the
> existence of vmap data at this point, or more simply something like a
> rectangle covering the vmap dataset.
>
> I found "Westernmost longitude", "Southernmost latitude", etc, in
> the 'lat'
> file at the root of each vmap directory, that could help me, but
> the values
> are empty ("-,-,-"). Is that normal ?

You can run the com.bbn.openmap.layer.vpf.Server class on any vpf
file to see what it contains. When I run it on my data, I get
boundaries for each library under that lat file. You should be able
to use the LibrarySelectionTable object to find the boundaries out
for you.

> I would also be interested by the same information for DTED data.
> The dmed
> file at the root of a dted dataset seems to contain the min and max
> coordinates covered by the data, like "N30N36W120W100". Can these
> values be
> retrieved using Openmap ?

OpenMap doesn't include a class to read the dmed file, we ignore it.
But, you can ask the DTEDFrameCache for the elevation at a certain
latitude/longitude.

The dmed file format is covered in the specification, it wouldn't be
hard to write something to parse and analyze it if you were
interested in doing it.

Regards,


- Don



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Received on Fri Jun 09 2006 - 10:10:52 EDT

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