[postgis-users] point to raster conversion

[Pierre Racine]

I would rather use the user custom function mapalgebra technique used in ST_ExtracToRaster() in the PostGIS Add-ons to extract a mean value for the group of point intersecting with each pixel. This should work well if 1) most pixels have points inside so there is no need to interpolate 2) it is possible to ST_Intersects() with the point patches (I didn't check much the Point Cloud API) and extract only intersecting points.

If the density of point is so low that many pixels do not have points inside then we then interpolate. But we don't have any interpolation method yet other than filtering functions implemented with neighbourhood map algebra.

Pierre

> -----Original Message-----
> From: postgis-users-bounces at lists.osgeo.org [mailto:postgis-users-
> bounces at lists.osgeo.org] On Behalf Of Rémi Cura
> Sent: Wednesday, December 18, 2013 10:05 AM
> To: PostGIS Users Discussion
> Subject: [postgis-users] point to raster conversion
> 
> Hey,
> 
> not very original question :
> I would like to convert parts of a point cloud into a raster.
> 
> I'm under the impression that currently this is more easily done outside
> PostGIS (with grass, gdal, R, or wathever).
> 
> I this simple process a good idea?
> 
> for each small part of point cloud (a patch)
> 
> 	get spatial extend
> 
> 	generate a raster covering this extand with givenpixel size and given
> bands
> 
> 	for pixel which intersects a point, set pixel band values with point
> attributes
> 
> 
> 
> Then (optionnal)
> for each raster
> 
> 	use efficient image processing code to interpolate
> 
> 
> Cheers,
> 
> Rémi-C