Opened 11 years ago

Closed 11 years ago

Last modified 11 years ago

#274 closed enhancement (fixed)

Explain Interior, Boundary and Exterior

Reported by: mloskot Owned by: kneufeld
Priority: medium Milestone: PostGIS 1.5.0
Component: postgis Version:
Keywords: Cc:


For completeness, it would be good to give short description of these three fundamental terms in the PostGIS manual:

The IBM Informix manual provides short but clear definitions of Interior, Boundary, and Exterior:

All geometries occupy a position in space defined by their interior, boundary, and exterior.
 * The exterior of a geometry is all space not occupied by the geometry.
 * The boundary of a geometry serves as the interface between its interior and exterior.
 * The interior is the space occupied by the geometry.

PostGIS manual could include similar.

Change History (5)

comment:1 Changed 11 years ago by pramsey

Owner: changed from pramsey to kneufeld

comment:2 Changed 11 years ago by kneufeld

Resolution: fixed
Status: newclosed

comment:3 Changed 11 years ago by mloskot


This is (uncensored word here ;-)) brilliant! I got way more than I asked for.

Just a few typos:

  • eachother
  • desireable

Perhaps Read from left to right could be completed with and from top to bottom too.

Also, I think it could be useful to add source reference to the Topogical/Clementini? operators, PDF at Dimensionally Extended Nine-Intersection Model (DE-9IM) by Christian Strobl

Thank you!

comment:4 Changed 11 years ago by mloskot

...or non-URL reference to "Encyclopedia of GIS" By Hui Xiong where it is DE-9IM perfectly explained for everyone who wants to dig details.

comment:5 Changed 11 years ago by kneufeld

Thanx Mateusz. I fixed the typos and add your noted references at the end of the section.

I like the pdf doc by Christian Stobl. Nice. I hadn't seen that one before. I was thinking along the same lines and would eventually like to see a simple de9im matrix in every spatial predicate definition (touches, crosses, within, etc) just as Christian has done in his doc. ... someday :)

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