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

[MAISONOBE Luc <luc.maisonobe@c-s.fr>]

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
Luc

> Kind regards,
> Carlos Krefft
> University of Miami



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