Changes between Version 14 and Version 15 of WKTRasterGSoC
- Timestamp:
- Mar 24, 2011, 2:01:47 PM (13 years ago)
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WKTRasterGSoC
v14 v15 32 32 1) '''ST_AsRaster''' takes a geometry and converts it to a raster. 33 33 34 2) '''ST_Interpolate''' takes a point (e.g. filtered lidar points) or line geometry (e.g. digitized topo lines) coverage to interpolate pixels values between geometries. There are numerous methods of interpolation and it would nice to have a generic method so we can use all of them, but we’re first targeting bilinear interpolation, which will fill most needs and lay the ground for other methods.34 2) '''ST_Interpolate''' takes a point (e.g. filtered lidar points) or line geometry (e.g. digitized topo lines) coverage to interpolate pixels values between geometries. There are numerous methods of [http://en.wikipedia.org/wiki/Interpolation interpolation] and it would nice to have a generic method so we can use all of them, but we’re first targeting [http://en.wikipedia.org/wiki/Bilinear_interpolation bilinear interpolation], which will fill most needs and lay the ground for other methods. For reference, you might want to check an implementation in [http://apps.nrbook.com/empanel/index.html Numerical Recipes (chap. 3)] 35 35 36 3) '''ST_AsDensity''' takes a point or line geometry coverage and first assign a count of those features to every pixels of a raster coverage and then apply a smoothing filter (using the existing one raster version of neighbour ST_MapAlgebra). Density functions allow summarizing or simplifying a point or line dataset. 36 37 3) '''ST_AsDensity''' takes a point or line geometry coverage and first assign a count of those features to every pixels of a raster coverage and then apply a smoothing filter (using the existing one raster version of neighbour ST_MapAlgebra). [http://www.spatialanalysisonline.com/output/html/Pointdensity.html Density functions] allow summarizing or simplifying a point or line dataset. 37 38 38 39 Want more details? Write to the [http://postgis.refractions.net/mailman/listinfo/postgis-devel PostGIS developer list].
