There is a 30 arc second resolution database of world topography much
of it compiled from an experiment on the space shuttle (mission STS-99
in year 2000) called "Shuttle Radar Topography Mission" (SRTM).
The dataset is free, but big(ish) at about 1.6GB. As far as I can
remember, sea areas are assigned a special elevation which
differentiates it from land. A quick google of "SRTM" yields pages
like this one:
http://eros.usgs.gov/srtm/data/obtainingdata.html.
To get an idea of the kind of resolution available have a look at this
beautiful image:
http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=16853
Joe.
On Jan 29, 2008 3:22 PM, David Ward <synriga_at_yahoo.com> wrote:
>
>
> You might be able to use an a Shape file representing land masses (i.e.
> dcwpo-browse) and test if the location is contain in a polygon. The accuracy
> near shorlines would be definitely be an issue.
>
> Othewise, you will need a terrain database with feature data against which
> you can query.
>
> Cheers,
> David
>
>
>
>
>
> ----- Original Message ----
> From: "Alvarez, Amaury A." <Amaury.Alvarez_at_gd-ais.com>
> To: openmap-users_at_bbn.com
> Sent: Monday, January 28, 2008 7:01:51 PM
> Subject: [OpenMap Users] determining if a lat/lon point is over land or over
> water
>
>
> Does OpenMap provide any support for determining if a
> specific lat/lon geospatial coordinate is over land or over water?
>
> -Amaury
>
> --
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Received on Tue Jan 29 2008 - 10:56:55 EST