tiling shape files, or shptree

[Tim Tsai]

On Wed, Apr 27, 2005 at 02:48:07PM -0400, Frank Warmerdam wrote:
> Tim / Schuyler,
>
> Yes, I've thought about that sometimes too.  It might be helpful to have
> a tool that would would copy a shapefile in .qix traversal order.  That
> is to reorder the features by locality as determined by the quadtree index.
> That might given the convenient managability of one big shapefile
> with the locality benefits of tiling.

  That should help clustering the blocks together.  I am not
very familiar with the .qix format but I don't think it actually
tries to balance the quadtree at all right now.  A mostly balanced
algorithm with a re-sorted shapefile might be a good approach.

  Also, I wonder what would happen if you run a big shapefile through
shp2tile, merge the shape files back sequentially into a big file,
then run shapetree on it.  Seems like you'd get most of the effects
of above.

  http://www.cs.umd.edu/~brabec/quadtree/ has lots of spatial
index algorithms.  One of these days I'll read through all of them.

  Tim