[postgis] Structure and Topology questions

Adrian Custer acuster at nature.berkeley.edu
Sun Jul 29 15:48:04 PDT 2001


I have some questions about the project that I hoped someone could

Someone said recently that PostGIS only supported 2-D +1 not true 3D. Is
this correct and if so could someone explain why this is being done?
Also the GML spec is still 2-D. I understood that PostGIS wanted to
support GML so what will it do about the lack of the third dimension?

PostGIS is ignoring the temporal nature of goemetric objects right now.
Is the vision envetually to support this? I've run across quite a few
situations where the same object must be represented differently at
different times. (Consider a series of digitized river centerlines where
the river meanders change between each photo. I would hope to be able to
describe the river as a single object but with multiple represntations
through time.)

What is the plan to develop/ construct topology? Is the vision that we
will be able to import a shapefile into a PostGIS layer and have it
construct the topology for complex queries to be done through the
database? I realize this is for the future but I didn't know if that was
the eventual plan. Does anyone have good information sources on the
constructioon of toplogical relationships in a realational database for
line networks, directed line networks (e.g. rivers), and plane objects
(e.g. a complete polygon coverage like a soil map)?


acuster at nature.berkeley.educational

------------------------ Yahoo! Groups Sponsor ---------------------~-->
Small business owners...
Tell us what you think!

To unsubscribe from this group, send an email to:
postgis-unsubscribe at yahoogroups.com


Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/ 

More information about the postgis-users mailing list