George Ionescu wrote:
Hello dear Noel,
hello all sqlite users,
a spatial extension for sqlite would be nice, although I think that
replacing the indexing scheme (e.g. replace the current b-tree with a
quad-tree or another spatial index) is alot of work.
Just some questions / thoughts:
1. How would you handle indexing? Would you replace completely the btree
with a spatial index (the hardest thing to do)? And if so, btree indexing
would still be available or not?
2. Go for GEOS's STRTree. It's the fastest spatial index I could find (I did
some research awhile ago on open-source solutions regarding spatial
indexes).
3. You might want to take a look at SpatialIndex
(http://u-foria.org/marioh/spatialindex/). The library is pretty clever
designed and it supports RSTAR-tree, MVR-tree and TPR-tree. The problem I
found with this library was that it was slower than GEOS at the time I last
checked. One of the features I like is that it allows persisting the index.
This might be an intermediate solution: you could store the index as a blob
in the database. It would not be very efficient (as efficient as replacing
indexing) but it would be a place to start.
4. Another nice library who might do the job is CGAL (http://www.cgal.org/).
I didn't benchmarked it mostly because GEOS suited my needs just fine, but
how knows, it might be better than the ones I mentioned.
George.
Hello George,
Thanks a lot for your input,
I don't plan to replace the normal indexing, I plan to have a set of
function to create a (memory ?) index. But how do I retrieve the data
without doing a select where rowid = xxx ?
Best regards
--
Noël Frankinet
Gistek Software SA
http://www.gistek.net
