[postgis-devel] ST_Buffer in 3D supporting Z

[Olivier Courtin]

On May 3, 2012, at 5:31 PM, Sam Hariton wrote:

Hi Sam,

> Is the Paris Sprint likely to result in a decision about GEOS/Boost/CGAL/PostGIS core/etc.?  
> Or is it a longer term discussion than that?

Well PostGIS (quite) always worked with GEOS, and we have good 
reasons to believe that it will continue for a while.

But maybe some new features (or better performances ?) could be 
also provide by others additional libs.
At this stage there's no strong opinion on what we have/want to do.

Paris place could be a way to exchange point of views and/or 
to process experimentations, and maybe prepare later PSC decisions.
(and as Regina said nothing will be set in stone in Paris)

> In the meantime, looking through the ticket list, there's a couple
> tickets (#430 and #428) that look interesting and I'd like to make
> a stab at.  What's the proper etiquette for doing so?


For 430
 - For these one there's mainly ST_AsCollada missing, as
   GeomFromGML, ST_AGML, and ST_AsX3D are already 
   implemented.
   
   An example could be used as a template is lwout_wkt.c
   
   But if we want to implement it for the whole use cases, theres several
   others issues:

   Texture handling will be an issue to think about.
   
   Max number of triangles handled by Collada, too (~21845) 
   so surely a simplification algorithm could be a day a need too ?
   (a bit as ST_Simplify but for 3D)

   Ability to triangulate to switch from PolyhedralSurface to Tin also.
   
   And last be not least Z altitude could be relative to ground or 
   geocentric.


For 428
 - These one is also a bit more tricky. It could be a good idea to 
   explore, if CGAL provide some primitive to handle it rightly.
   (dunno right now)



On theses topic any help is very welcome ! 
:)


--
Olivier Courtin
Oslandia
+33 977 217 501





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