Hugh, Your worldview is showing (don't be embarrassed). If you're going to shell out "big bucks" for ESRI, why not shell those bucks to the PostGIS development community (*cough*) and get the feature you need added? P.
On Mon, Jul 19, 2010 at 3:14 PM, Hugh Stimson <h...@hughstimson.org> wrote: > Thanks for your reply Ralf. > > Since posting my query I've found this helpful chart of functions with their > 2.5d support: > > http://postgis.refractions.net/docs/ch08.html#PostGIS_TypeFunctionMatrix > > According to that, the ST_Intersects and ST_Intersection functions aren't > yet 2.5d enabled. So I'm guessing that means that while they will accept > data with an assigned Z, as you suggest, only the x/y dimensions will be > considered in determining if they are coincident. > > That isn't sufficient for the application I'm working on, I need to be able > to distinguish the case where one object passes over another one without > actually touching. The shapes involved are complex enough that using a > simple elevation rule to pre-filter can't account for all possible > situations. > > Might have to shell out the big bucks for an ESRI license. Ouch. > > cheers, Hugh > >> Hi Hugh, >> >> all functions in PostGIS will work on 2.5D data. So you have to add an >> extra >> condition for your z-range. >> >> Gr >> Ralf >> >> Am Freitag 16 Juli 2010, 23:32:03 schrieb Hugh Stimson: >>> >>> Hi PostGIS folks, >>> >>> I'm trying to find a way to read two 3-dimensional polygons and test if >>> they intersect. It's for a radar-bird-tracking application. I'm hoping >>> that PostGIS is a solution. >>> >>> I've been scanning the Mailing list archives, and I gather that at least >>> some of the spatial operations which PostGIS provides are 3d-enabled. >>> Which surprises me, as my understanding was that PostGIS spatial >>> operations descend from the Java Topological Suite via GEOS, and JTS >>> advertises itself as being specifically for 2-d linear modelling. >>> >>> Could I count on the ST_Intersects function to work with 3d data? Would >>> there likely be any special considerations for 3d? >>> >>> >>> http://postgis.refractions.net/documentation/manual-1.5/ST_Intersects.html >>> >>> cheers, >>> >>> Hugh > > -- > Hugh Stimson / 778.373.1024 / hughstimson.org > _______________________________________________ > postgis-users mailing list > postgis-users@postgis.refractions.net > http://postgis.refractions.net/mailman/listinfo/postgis-users > _______________________________________________ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users
