[postgis-users] "Summarizing" a collection of geometries

[Paul Ramsey]

Interesting jumping off point for a discussion of new technology ideas...

- heatmap in the database
- contouring in the database
- kriging in the database (I know, already there w/ R)

P

On Mon, Apr 21, 2008 at 3:55 PM, Reid Priedhorsky <reid at umn.edu> wrote:
> Dear list,
>
>  I would like to compute a "summary" of a collection of geometries (points,
> linestrings, polygons, or any combination).
>
>  Here is the use case. I would like to summarize the geometry collection and
> present this summary visually so users working at a small scale can see,
> "ah, if I zoom in here, I can see more details about this geometry
> collection".
>
>  The simple solution would be to compute a convex hull or bounding box, but
> this fails if the members of the collection are far apart (users could zoom
> into the middle and see nothing). In this case the summary would need to be
> a multipolygon. But the trick is figuring out when to split summary polygons
> into multipolygons.
>
>  Has this been done? Do any of you have suggestions or references?
>
>  It is very preferable to do this entirely in the database rather than in
> external code. Embedded procedures are fine.
>
>  As you can see I am not entirely sure of my terminology, so any suggestions
> there would be welcome as well.
>
>  Many thanks,
>
>  Reid
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