[postgis-devel] [PostGIS] #1176: [raster] Two raster ST_Intersects
PostGIS
trac at osgeo.org
Mon Sep 12 15:08:02 PDT 2011
#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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