[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):

 This can get pretty dicey pretty quick. My algorithm applies a nearest
 neighbor sampling of "big" using indices derived from "small". It could be
 that the pixel from "small" actually straddles the dividing line between
 two to four pixels from "big", and further, it could be "more in" the
 NODATA pixel and get missed. I suspect that checking adjacent pixel(s)
 from big which are "within" one small pixel distance could help. However,
 one cannot assume that the two rasters are aligned and this may throw a
 wrench in the works.


 IIRC, using a 3x3 kernel does not typically mean you get to advance by
 three pixels with every iteration. Normally, you center the 3x3 kernel on
 every pixel, perform the operation, and move to the very next pixel. I'm
 not sure I understand what you're proposing to do or how it would catch
 intersections in the skipped pixels. We may need to start drawing
 pictures.

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Ticket URL: <http://trac.osgeo.org/postgis/ticket/1176#comment:9>
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