Re: Special query type for Spatial DB

"Arthur Yeo" <ayeo_at_acm.org> wrote in message news:a79bf3a3.0401271051.6be0ce27_at_posting.google.com...
> "Mikito Harakiri" <mikharakiri_at_iahu.com> wrote in message
news:<BXUNb.8$KI3.136_at_news.oracle.com>...
> > Your question has many interpretation. What is the universe of
discourse? Is
>
> The other issue is that the universe of discourse may be more
> ordered/evenly-spaced out than what we were talking about; e.g.
> honeycomb cells or nuclear-reactor uranium rods.
>
> So, I guess density map will not reveal much since they are all evenly
> spaced; unless, we use a different property to create the density map,
> such as free honeycomb cells (i.e. not occupied by eggs or larvae.)

If some cells are empty, density can't be uniform. It doesn't matter what your space is. Consider 2 dimensional grid of integers:

{(x,y) where x and y are integers}

with distance defined for example as

||a,b|| = |a_x-b_x|+|a_y-b_y|

then density map of order 5 matches every filled-in node on the grid with minimal diameter of a cluster containing a that node plus 4 other filled-in nodes. Received on Thu Jan 29 2004 - 02:53:27 CET