Subject: Re: [geometry] 3D box -> 3D multi_polygon conversion
From: Barend Gehrels (barend_at_[hidden])
Date: 2013-06-11 15:25:36
On 11-6-2013 21:13, Tomislav Maric wrote:
> Thank you Barend.
> I'll dig around and try to see what I need to do to get things running
> for 3D. Any suggestions regarding where should I start and what needs to
> be done?
A lot needs to be done there...
Note that converting a box to e.g. a ring is not that simple. A 3D box
has two z-coordinates, which cannot be just converted into a ring with
height, you will loose one coordinate. Unless you define a ring with two
z-coordinates (ground and height), which is basically possible, but that
will make the conversion less generic.
What is basically implemented for 3D is, out of my head:
- the concepts are dimension-agnostic, so for example get/set
- some dimension-agnostic algorithms (of course) as num_points,
num_geometries, reverse, unique, for_each
- distance (3D points or actually N-D points)
- centroid (idem) for point collections
- derived from distance: length (3d segments or linestrings, or n-d) /
- derived from distance: simplify
- conversion to WKT/DSV
- some in details are basically N-D but never tested as such, or will
only work with (probably minor) fixes, such as sectionalize
What we need is a polyhedron, and then operations on it, which will be a
major work on itself.
Bruno has certainly more ideas about this.
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