Martin Landa wrote: > Hi Markus, > > 2009/7/7 Markus Metz <[email protected]>: > > [...] > > >> For the time being, the only reasonable way to deal with these massive >> datasets is to *not* build topology. It's not not only the spatial index >> that is getting out of hand, also topology itself and the category >> index. The grass vector libs must be told that there is nothing special >> about point datasets (to cite Hamish) which means rewriting major parts >> of the vector libs, and that takes time. >> > > BTW, are you planning to commit your changes in sidx to trunk? > Yes, after I'm done with testing. I have the probably unrealistic aim to get building the new file-based spatial index as fast as the current memory-based index, and I still have to implement the new memory-based version, currently it's all file-based. I have polished the file-based version with R*-tree methods and speed optimizations (amongst others a custom quicksort), but adjusting the grass vector libs to use either the memory-based version or the file-based version is really a lot of work. It will take me at least another week to get it right, e.g. decide what tasks should be done by Vlib and what tasks should be done by diglib, and how the two should work together. I can send you a detailed technical report if you want, but I'm afraid it will be very technical and potentially boring unless you are interested in performance differences between Toni Guttmann's RTree and Norbert Beckmann's R*-tree. I would need some help to get random file access optimized, it's not too bad in my tests but I don't know if it can get better.
Markus M _______________________________________________ grass-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-dev
