v.build.pg

Builds PostGIS topology for vector map linked via v.external.

Command linePython (grass.script)

v.build.pg [-p] map=name [topo_schema=name] topo_column=name [tolerance=float] [--overwrite] [--verbose] [--quiet] [--qq] [--ui]

Example:

v.build.pg map=name topo_column=topo

grass.script.run_command("v.build.pg", map, topo_schema=None, topo_column="topo", tolerance=1, flags=None, overwrite=False, verbose=False, quiet=False, superquiet=False)

Example:

gs.run_command("v.build.pg", map="name", topo_column="topo")

Parameters

Command linePython (grass.script)

map=name [required]
    Name of vector map
topo_schema=name
    Name of schema where to build PostGIS topology
    Default: topo_<map>
topo_column=name [required]
    Name of topology column
    Default: topo
tolerance=float
    Tolerance to snap input geometry to existing primitives
    Default: 1
-p
    Don't execute SQL statements, just print them and exit
--overwrite
    Allow output files to overwrite existing files
--help
    Print usage summary
--verbose
    Verbose module output
--quiet
    Quiet module output
--qq
    Very quiet module output
--ui
    Force launching GUI dialog

map : str, required
    Name of vector map
    Used as: input, vector, name
topo_schema : str, optional
    Name of schema where to build PostGIS topology
    Default: topo_<map>
    Used as: name
topo_column : str, required
    Name of topology column
    Used as: name
    Default: topo
tolerance : float, optional
    Tolerance to snap input geometry to existing primitives
    Default: 1
flags : str, optional
    Allowed values: p
    p
        Don't execute SQL statements, just print them and exit
overwrite: bool, optional
    Allow output files to overwrite existing files
    Default: False
verbose: bool, optional
    Verbose module output
    Default: False
quiet: bool, optional
    Quiet module output
    Default: False
superquiet: bool, optional
    Very quiet module output
    Default: False

DESCRIPTION

v.build.pg builds PostGIS topology for feature tables linked via v.external.

NOTES

Note that PostGIS Topology extension is currently under development. v.build.pg requires PostGIS 2.0.0+.

Existing PostGIS topology schema can be overwrite by --overwrite flag.

v.build.pg calls PostGIS functions:

1. CreateTopology() to create topology schema in the database,
2. AddTopoGeometryColumn() to add a topogeometry column to an existing feature table, and
3. toTopoGeom() to create a new topo geometry from the simple feature geometry.

EXAMPLES

Workflow example

Export vector map into PostGIS:

v.out.ogr input=bridges output=PG:dbname=pgis_nc format=PostgreSQL

Create a new vector map as a link to PostGIS table:

v.external input=PG:dbname=pgis_nc layer=bridges

Check metadata:

v.info map=bridges

...
 |----------------------------------------------------------------------------|
 | Map format:      PostGIS (PostgreSQL)                                      |
 | DB table:        public.bridges                                            |
 | DB name:         pgis_nc                                                   |
 | Geometry column: wkb_geometry                                              |
 | Feature type:    point                                                     |
 |----------------------------------------------------------------------------|
...

Build PostGIS topology for the link:

v.build.pg map=bridges

...
Topology topo_bridges (6), SRID 900914, precision 1
10938 nodes, 0 edges, 0 faces, 10938 topogeoms in 1 layers
Layer 1, type Puntal (1), 10938 topogeoms
 Deploy: public.bridges.topo
...

Dry run

For testing issues use -p flag.

v.build.pg map=bridges

Creating new topology schema...

SELECT topology.createtopology('topo_bridges', \
find_srid('public', 'bridges', 'wkb_geometry'), 1)

Adding new topology column...

SELECT topology.AddTopoGeometryColumn('topo_bridges', \
'public', 'bridges', 'topo', 'point')

Building PostGIS topology...

UPDATE bridges SET topo = topology.toTopoGeom(wkb_geometry, \
'topo_bridges', 1, 1)


SELECT topology.TopologySummary('topo_bridges')

SEE ALSO

v.external, v.out.ogr, v.out.postgis, v.build

AUTHOR

Martin Landa, Czech Technical University in Prague, Czech Republic

SOURCE CODE

Available at: v.build.pg source code (history)
Latest change: Thursday Feb 20 13:02:26 2025 in commit 53de819