[postgis-devel] [PostGIS] #493: [wktraster] ST_DumpValues to Dump Pixel values

[PostGIS]

#493: [wktraster] ST_DumpValues to Dump Pixel values
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  Reporter:  robe       |       Owner:  pracine         
      Type:  defect     |      Status:  new             
  Priority:  medium     |   Milestone:  WKTRaster Future
 Component:  wktraster  |     Version:  trunk           
Resolution:             |    Keywords:                  
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Comment (by pracine):

 Could you describe a little bit how you use ST_Value? I was not thinking
 about implementing complex pixel value access functions. Normally you
 could access pixel values of any part of the raster with
 ST_AsText(ST_Clip(rast, geom)) which are not implemented yet. Would this
 fulfill your needs?

 Remember also that WKT Raster main intented use it to work with huge
 tilled coverage. Every tile should be something like 128 x 128 pixels. The
 same way you don't use PostGIS to do analysis or publish small shapefiles
 (better do it with a desktop application), you don't normally use WKT
 Raster do work with small images but with complete coverages, and those
 are workable only when tiled.

 I say that because you don't nesessarily access pixel values in a tiled
 coverage the same way you access them in an image. I would strongly
 suggest you experiment and build users cases with tiled coverages. This
 should have a major impact on the way you see WKT Raster and the function
 you think you need. You can build a coverage by importing images with the
 -k option of gdal2wktraster.py. I think working with tiled coverage is
 closer to what people will actually do with WKT Raster.

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Ticket URL: <http://trac.osgeo.org/postgis/ticket/493#comment:2>
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