
Geometry : 
Subject: [ggl] Questions about Boost.Geometry
From: Dragos Chirila (dchirila)
Date: 20110518 09:40:46
Dear all,
This is my first message on this list, so please excuse my lack of
experience.
I am developing a small C++ framework (which I plan to release as
opensource soon), focusing on postprocessing of climate datasets. Some
computational geometry is a necessary component (for example, for filtering
data inside a polygon on the sphere). For this component, I am currently
trying to implement a separate library.
However, recently I read about the arrival of Boost.Geometry/GGL in Boost
v1.47, and after trying some of the examples it seems quite exciting.
However, I would like to ask several questions:
1. (Approximately) when will the "official" Boostversion be released? I am
already using other Boost libraries, and my core users would prefer to use a
single, stable Boost package.
2. For an initial version of my software, simple spherical coordinates would
suffice. Therefore, can Boost.Geometry (using the spherical coordinate
system):
a) determine whether a GeoLocation (lon, lat) lies inside a GeoPolygon
(specified as a vector of (lon,lat)pairs)?
* This is not a problem for my geometric routines, since I can use a
cylinder projection, then compute as in the plane case. But can this be
easily achieved with Boost.Geometry?
b) compute the area of intersection between two GeoPolygons?
* This is actually one of my biggest problems, since my (nonspecialist)
solution is to:
 project both GeoPolygons onto a plane cutting the sphere;
 compute the clipping polygon in 2D, then
 project back on the sphere and
 compute the area of the spherical polygon.
This does not feel like a good solution, and has many limitations (depending
on the size of the GeoPolygons, a projection plane might not exist, in which
case I have to divide them and try to repeat the procedure). So, is this
possible (maybe trivial) in Boost.Geometry?
I hope this is the right place for these questions. Any input would be
greatly appreciated!
Respectfully,
Dragos
 ================================================ = Dragos B. Chirila = Computational Physicist, PhD candidate = Alfred Wegener Institut Bremerhaven, University of Bremen = +49017632057856 ================================================  next part  An HTML attachment was scrubbed... URL: http://lists.osgeo.org/pipermail/ggl/attachments/20110517/6726c708/attachment.html
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