PostGIS topological editing

Goal: Implement ​PostGIS geometry (simple features and topological) editing functionality in GRASS GIS (wxGUI digitizer and v.edit module) using GRASS-PostGIS data provider.

See also GRASS-OGR data provider and wxGUI vector digitizer roadmap.

See also user-oriented ​page at GRASS ​User Wiki.

Tasks

1. Attribute table (write) access for OGR-linked vectors (direct or linked by v.external) (implemented in r47225)
2. Improve OGR interface write access (in progress) - see OGR Interface (see r50670)
3. Implement PostgreSQL driver to read PostGIS geometry directly (without using OGR library) - see grass/trunk/lib/vector/Vlib/read_pg.c​
4. Extend PostgreSQL driver to write PostGIS geometry directly (without using OGR library) - see grass/trunk/lib/vector/Vlib/write_pg.c​
5. Implement PostGIS-based topology management in PostgreSQL driver
6. Implement GRASS-based topology management in PostgreSQL driver
7. Add more...

Known issues

• v.build opt=cdump produces empty output

Topology models in GRASS and PostGIS

Topological elements in GRASS (see ​API manual):

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

Topological elements in PostGIS (see ​PostGIS's wiki):

• Nodes
• Edges
• Faces

References

• ​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

• v.out.postgis - export GRASS vector map to PostGIS feature table or topology schema
• v.topo.pg.out​ - converts GRASS topology to PostGIS
• v.build.pg​ - builds PostGIS Topology for GRASS vector map