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Re: [Orekit Users] DihedralFielOfView with a Polygon instead of a PVCoordinatesProvider PVTarget point.

You would have line of site field of view to a region long before you fly over it however.  I agree this would be an interesting thing to implement and it being useful.

On Wed, Jan 29, 2014 at 3:44 PM, MAISONOBE Luc <luc.maisonobe@c-s.fr> wrote:
Carlos Krefft <ckrefft@rsmas.miami.edu> a écrit :

I'm looking for a way to make a DihedralFielOfViewDetector detect Visibility against an AOI polygon instead of PVTarget. Is this possible?

It will be possible in the next version, that will depend on Apache Commons Math 3.3. This version of Apache Commons Math includes a way to define arbitrary shapes on the sphere and to compute things like distance to the boundary and hence accurate crossing time. This work for simple polygons on the sphere, but also for more complex cases with zones defined in several disconnected parts, non-convex areas, areas with holes, areas including the pole ...

This will be used for two things in Orekit :

 - creating an event handler for spacecrafts flying over zones of
   interest (say a country, even considering separate islands, or
   excluding inner lakes if you want)
 - creating an event handler for arbitrary shaped on-board fields
   of view.

I think what you want is exactly what we are doing right now!

The code for the first event handler is almost ready (it is just quite slow for complex shapes, so I have to improve it). The code for the second event handler does not exist but can be done in a matter of hours. The most important thing to remember is that this induces a dependency to Apache Commons Math 3.3, and this version of the library is not released yet. It is expected to be released soon, but we have no date.

Any tips or help would be greatly appreciated.

Hope this helps

Kind regards,
Carlos Krefft
University of Miami

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