
Geometry : 
Subject: [ggl] RE: A few Boost.Geometry questions
From: Bruno Lalande (bruno.lalande)
Date: 20100930 10:30:43
> Concept refinement handles cases where 3D points need to be used in 2D algorithms. ?For things like properties if your algorithm modifies the geometric content of the argument passed by reference the properties will be preserved. ?We could think of the z as a property in this case. ?If it constructs new ones in the output the properties won't be transferred to the output. ?If it uses the copy constructor to construct the new ones it would. ?If you want to support this kind of thing you'll need to test for it since it os easy to overlook.
Actually I'm not sure what you want exactly here, Bill. Let's say you
want the intersection between a shape made of such 2D points with a z
value and another 2D shape (with no z values, or z values you don't
care about). If the algorithm must create a point in the middle of a
segment of the first shape and the z values of the ends of this
segment are 10 and 20, do you want the created point to have z value
15? If yes, it sounds like you simply need an algorithm taking a 3D
geometry on one hand and a 2D geometry on the other hand, right?
Thanks
Bruno
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