[postgis-users] PostGIS topology ISO SQL/MM complete

[José Carlos Martínez Llario]

Hi Sandro,
This is great news!!
I think many people were waiting for a persistent topology model.
There is already some performance bechmark comparing the simple  
feature model with the persistent topology model about quering,  
writing topo geometries, etc. specially talking about face primitives?

Congratulations to the PostGIS team.
Best
Jose



Sandro Santilli <strk at keybit.net> escribió:

> [http://strk.keybit.net/blog/2011/10/14/postgis-topology-iso-sqlmm-complete/]
>
> PostGIS implementation of the ISO SQL/MM Topology-Geometry model
> is finally complete [1].
>
> The SQL/MM model [2] is just a portion of the whole topology support [3],
> but an important one, including schema definition and functions to create
> and populate the schema with primitive components (nodes, edges, faces).
>
> In addition to the base model, PostGIS adds a TopoGeometry [4] data type
> for use wherever you would normally use a Geometry type, except the
> former will be defined by references to primitive, shared, topological
> components.
>
> The work on SQL/MM topology for PostGIS 2.0 was mainly funded by the Land
> Management department of the Tuscany Region as part of a larger project
> aimed at enhancing effectiveness of free software tools already in use
> within the institution for the management of the topographic database.
>
> But more work is needed to make it easier to convert your layers to
> topological layers, your Geometries to TopoGeometries [5]. Because I know
> you want to generalize your vectors in a topologically consistent way,
> don?t you ? And you want to edit the boundaries just once. And do you
> want to waste all that space for your triangles ?
>
> Feature freeze for 2.0 will be at the end of November.
> Please drop a note if you?d like to help with getting the
> enhanced TopoGeometry constructor [5] shipped with it !
>
> [1] http://trac.osgeo.org/postgis/changeset/7886
> [2] http://pdfqueen.com/h2-topo-geo
> [3] http://postgis.refractions.net/documentation/manual-svn/Topology.html
> [4] http://trac.osgeo.org/postgis/wiki/UsersWikiTopoGeometry
> [5] http://trac.osgeo.org/postgis/ticket/1017
>
>
> --strk;
>
>   ()   Free GIS & Flash consultant/developer
>   /\   http://strk.keybit.net/services.html
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>



------------------------------
José Carlos Martínez Llario

Producción Cartográfica y SIG.
Dpto. Ingeniería Cartográfica.
Univ. Politécnica de Valencia.

E-mail: jomarlla at cgf.upv.es
Telf: 963877007 ext. 75599
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