Changes between Initial Version and Version 3 of Ticket #502


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Timestamp:
Jun 7, 2010, 1:51:41 PM (14 years ago)
Author:
pracine
Comment:

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  • Ticket #502

    • Property Status newreopened
    • Property Summary [wktraster] Optimize ST_Intersection when the geometry is a point[wktraster] Optimize ST_Intersection
  • Ticket #502 – Description

    initial v3  
    1 It might be much quicker to provide the value associated with a pixel intersecting with a point geometry when using ST_Intersection() by accessing the pixel value with ST_Value instead of vectorizing the whole tile. This, obviously, do not work when the intersecting geometry is a polygon. In this case we have to vectorize the complete raster tile.
     1It might be much quicker to provide the value associated with a pixel intersecting with a point geometry when using ST_Intersection() by accessing the pixel value with ST_Value instead of vectorizing the whole tile. We have first to fix st_value(rast, geom) so it behave exactly as st_intersect on edge of raster and pixels.
     2
     3This, obviously, do not work when the intersecting geometry is a line or a polygon. In this case we should try to vectorize only the intersecting part of the raster tile.