To clarify, what I'm looking for is exactly the inverse operation to "gridding" as defined here:
http://www.gdal.org/grid_tutorial.html This is much simpler and it's not difficult to write the low-level code myself, but it seems quite strange to not have a high-level interface. Is there really no interface, or am I just inadequate at reading the docs? On Tue, Apr 26, 2011 at 01:24, Jed Brown <[email protected]> wrote: > I have a bunch of unstructured points, typically quadrature nodes of an > unstructured mesh, and I want to sample a raster field at those points. I > have plenty of spatial locality, but not any specific regular structure. > Maybe I'm missing something, but I don't see an API for this direction. > > There is GDALCreateTPSTransformer which would seem to be a reasonable way > to go from an unstructured mesh to a raster. But it's not easy to go the > other way since it would involve, e.g. defining a (bad) quadrature using the > raster and then do a Galerkin projection into the unstructured finite > element basis, then evaluate that basis at the unstructured quadrature > nodes. Alternatively, we could make tiny regular patches in the unstructured > grid and do lots of independent projections, but I worry that this would be > a performance issue. > > Is there a recommended way to sample a raster field at unstructured points? >
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