Re: Line-of-Sight

Hi Oscar,

On Wednesday, August 22, 2001, at 07:49 AM, OPW Abbenhuis wrote:

> Hi,
>
> I am quite new to OpenMAP. Seen a demo working and was
> quite impressed. Even more when I checked the API documentation.
>
> For a project (simulation model) we need to work with DTED
> and DFED data. I have seen that there already is a layer
> for DTED. This layer has the functionality to get the elevation
> at a certain point, either via the closest point available or via
> interpolation.
>
> I am wondering how difficult it would be to implement
> line of sight which (I think) depends on DTED and maybe
> also DFED data. Or is this also standard functionality?

The TerrainLayer does a couple things with terrain analysis. It can
create a LOS mask from a central point and height, out to a certain
radius. It can also create an elevation profile between two points. It
wouldn't be too hard to come up with a LOS calculation between two
points - it would take parts of the two algorithms.

The one thing that should change with the current architecture is that
the DTEDLayer and TerrainLayer have duplicate frame caches. I;d like to
have the DTED data provided as a service to any component that needs
elevation data. I don't know when those changes will happen (depends on
potential user support/funding).

> In addition we also need to calculate if a line/route
> will intersect with the surface.

That isn't currently implemented, but sounds like a simple extension of
the profile analysis.

We currently don't handle DFAD data, either, but it could certainly be
integrated into the calculations. I would install it into a database
and check it as the route profile is generated.

Hope this helps,

Don

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Donald F. Dietrick, dietrick@bbn.com
BBN Technologies, 10 Moulton Street, Cambridge, MA 02138
617.873.3031 FAX 2794
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