[postgis-tickets] [PostGIS] #2327: [raster] ST_Drape

[PostGIS]

#2327: [raster] ST_Drape
-------------------------+--------------------------------------------------
 Reporter:  dustymugs    |       Owner:  dustymugs     
     Type:  enhancement  |      Status:  new           
 Priority:  medium       |   Milestone:  PostGIS Future
Component:  raster       |     Version:  trunk         
 Keywords:               |  
-------------------------+--------------------------------------------------
 Taking a geometry and a raster, return a new XYM geometry resulting from
 overlaying the geometry on the raster and populating M with values from
 the raster.

 Reference:

 http://vterrain.org/Misc/draping.html

 {{{
 geometry ST_Drape(
   rast raster, nband int,
   geom geometry,
   computed_vertices boolean DEFAULT TRUE
 )
 }}}

 Some things to think about before implementing...

 1. XYM or XYZ output geometry: Assuming the raster is DEM, units are
 typically meter or foot. If X/Y are degrees, populating Z in the DEM's
 units don't make sense.  Maybe a function parameter flag indicating output
 should be XYZ or XYM?

 2. 3D geometry with rasters: The geometry is treated as 2D. Should pixel
 values be put into Z or M?

 3. computed_vertices: The returning geometry should be as detailed as the
 input raster. So, returning geometry will have the same vertices of the
 input geometry and possibly.

 4. Polygons: How to handle the interior of the polygon?  Boundary is easy.
 Multipolygon?  TIN?

-- 
Ticket URL: <http://trac.osgeo.org/postgis/ticket/2327>
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