[[TOC]]
= PostGIS topological editing =

'''Goal''': Implement [http://www.postgis.org PostGIS] geometry (simple features and topological) editing functionality in GRASS GIS (wxGUI digitizer and {{{v.edit}}} module) using [wiki:Grass7/VectorLib/PostGISInterface GRASS-PostGIS data provider].

See also [wiki:Grass7/VectorLib/OGRInterface GRASS-OGR data provider] and [wiki:wxGUIDevelopment#Vectordigitizer wxGUI vector digitizer] roadmap.

See also user-oriented [http://grass.osgeo.org/wiki/PostGIS_Topology page] at GRASS [http://grass.osgeo.org/wiki User Wiki].
== Tasks ==

 1. ~~Attribute table (write) access for OGR-linked vectors (direct or linked by {{{v.external}}})~~ (implemented in r47225)
 1. ~~Improve OGR interface write access (in progress) - see [wiki:Grass7/VectorLib/OGRInterface OGR Interface]~~ (see r50670)
 1. ~~Implement PostgreSQL driver to read PostGIS geometry directly (without using OGR library)~~ - see [source:grass/trunk/lib/vector/Vlib/read_pg.c]
 1. ~~Extend PostgreSQL driver to write PostGIS geometry directly (without using OGR library)~~ - see [source:grass/trunk/lib/vector/Vlib/write_pg.c]
 1. ~~Implement PostGIS-based topology management in PostgreSQL driver~~
 1. ~~Implement GRASS-based topology management in PostgreSQL driver~~
 1. Add more...


== Topology models in GRASS and PostGIS ==

Topological elements in GRASS (see [http://grass.osgeo.org/programming7/vlibTopology.html API manual]):

 * Nodes
 * Lines (lines, boundaries, centroids)
 * Areas
 * Isles

Topological elements in PostGIS (see [http://trac.osgeo.org/postgis/wiki/UsersWikiTopologicalPrimitives PostGIS's wiki]):

 * Nodes
 * Edges
 * Faces



== References ==

 * [http://postgis.org/documentation/manual-svn/Topology.html PostGIS Topology]
 * http://strk.keybit.net/blog/2011/10/14/postgis-topology-iso-sqlmm-complete
 * http://grass.osgeo.org/wiki/PostGIS_Topology
== See also ==

 * https://github.com/strk/qgis_pgis_topoedit

== Related modules ==
 
 * [source:grass/trunk/vector/v.out.postgis v.out.postgis] - export GRASS vector map to PostGIS feature table or topology schema
 * [source:sandbox/martinl/v.topo.pg.out v.topo.pg.out] - converts GRASS topology to PostGIS
 * [source:grass-addons/grass7/vector/v.build.pg v.build.pg] - builds PostGIS Topology for GRASS vector map