Hi fork On 2012/5/8 fork <forkandw...@gmail.com> wrote: > Does anyone know of an exhaustive reference of DE-9IM matrices, with pictures?
I don't think I would call it a reference but take a look http://labs.geometa.info/postgisterminal/?xapi=node[tourism=zoo] : There is a menu item "Relate exemplified (bool)" which displays parameters as as list of pictures (disregarding of the current query). Choose the two geometry types and the DE-9IM pattern, then click on "[+]" and look at the prerendered pictures. Pls. give feedback if you have any suggestions. -S. > Context: > > I just finished classifying a bunch of polygons based on their relationship to > enveloping poly's in another layer (census blocks and census city boundaries, > respectively). The regular old st_within() and friends weren't enough, so I > calculated all the DE-9IM's, counted them (yay for GROUP BY and real > databases!), and made sure I knew what was going on for each of the matrices > returned (7 total). Then I classified my block polys based on the strings. > > I found it CRAZY how many different types of DE-9IM's could be returned, even > with just polygons and very well aligned boundaries (credit to the US Census > Bureau's geography division). Only a few of the matrices in my data were > actually described in the few docs I could find. Besides the seven in my > data, > there are at least four more that can be generated by various combinations of > overlapping polygons. > > It would have been much easier to do this project if I had been able to > reference a list of possibilities along with pictures. It would be even > better > if I could be confident that such a list was exhaustive. > > Does anyone have a reference? > > If not, I could continue to work on an atlas of DE-9IM matrices, at least for > polygons, and submit it somewhere if it were helpful. Any ideas for where > that > might go? (I don't have a blog and don't want to start one). Maybe just the > wikipedia entry? > > For those who don't know, a DE-9IM matrix is the output of st_relate(geo1, > geo2), and there is an excellent intro in the docs. Fascinating stuff really. > > Tx > > _______________________________________________ > 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
