[postgis-devel] [PostGIS] #1176: [raster] Two raster ST_Intersects

[PostGIS]

#1176: [raster] Two raster ST_Intersects
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 Reporter:  dustymugs       |       Owner:  dustymugs    
     Type:  enhancement     |      Status:  assigned     
 Priority:  medium          |   Milestone:  PostGIS 2.0.0
Component:  postgis raster  |     Version:  trunk        
 Keywords:                  |  
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Comment(by bnordgren):

 Replying to [comment:14 pracine]:
 > I know this seems to be a nice case for Bryce's iterator but I still
 need a demonstration that this iterator is more
 simple/flexible/fast/useful than the iterator used in the two raster
 ST_MapAlgebra plpgsql prototype (not unnecessarily introducing the concept
 of mask by the way :-).

 The iterator part of gen2 has been written for a while, although I still
 need to expose it up to the SQL layer. For your application, it's main
 feature is that it's accessible (e.g., it's not in the middle of some
 other function.)

 However, I was thinking about it and I don't think you want either my
 iterator or mapalgebra's. You want to stop iterating at the first true
 value, and neither iterator does that. (And I really don't think we should
 add that feature to either iterator.) Likewise, you don't care about
 storing the result for every pixel: you just need a single true/false at
 the end. I think these features are common to all of the DE-9M tests. This
 may be worth writing a second iterator which stops early and doesn't store
 per-pixel values.

-- 
Ticket URL: <http://trac.osgeo.org/postgis/ticket/1176#comment:15>
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