PostGIS Topology

PostGIS Topology je rozšíření pro PostGIS umožňující topologickou správu vektorových dat v prostředí PostGIS/PostgreSQL.

Více přednášky Úvod do zpracování prostorových dat.

Příklad

Feature table 'urbanarea'

\d urbanarea

                                    Table "public.urbanarea"
    Column    |       Type        |                          Modifiers                          
--------------+-------------------+-------------------------------------------------------------
 ogc_fid      | integer           | not null default nextval('urbanarea_ogc_fid_seq'::regclass)
 wkb_geometry | geometry          | 
 cat          | integer           | 
 objectid     | integer           | 
 ua           | character varying | 
 name         | character varying | 
 ua_type      | character varying | 
Indexes:
    "urbanarea_pk" PRIMARY KEY, btree (ogc_fid)
    "urbanarea_geom_idx" gist (wkb_geometry)
Check constraints:
    "enforce_dims_wkb_geometry" CHECK (st_ndims(wkb_geometry) = 2)
    "enforce_geotype_wkb_geometry" CHECK (geometrytype(wkb_geometry) = 'POLYGON'::text OR wkb_geometry IS NULL)
    "enforce_srid_wkb_geometry" CHECK (st_srid(wkb_geometry) = 900914)

SELECT cat, ua, name, ST_GeometryType(wkb_geometry) from urbanarea limit 5;

 cat |  ua   |    name    | st_geometrytype 
-----+-------+------------+-----------------
   1 | 29305 | Farmville  | ST_Polygon
   2 | 92404 | Washington | ST_Polygon
   3 | 35380 | Greenville | ST_Polygon
   4 | 46315 | La Grange  | ST_Polygon
   5 | 45397 | Kinston    | ST_Polygon

Vytvoření topologického schématu 'urbanarea'

SELECT topology.createtopology('urbanarea');

SELECT * from topology.topology;

 id |   name    | srid | precision 
----+-----------+------+-----------
  1 | urbanarea |   -1 |         0

\dt urbanarea.

           List of relations
  Schema   |   Name    | Type  | Owner  
-----------+-----------+-------+--------
 urbanarea | edge_data | table | martin
 urbanarea | face      | table | martin
 urbanarea | node      | table | martin
 urbanarea | relation  | table | martin

\d urbanarea.node
                                    Table "urbanarea.node"
     Column      |   Type   |                            Modifiers                             
-----------------+----------+------------------------------------------------------------------
 node_id         | integer  | not null default nextval('urbanarea.node_node_id_seq'::regclass)
 containing_face | integer  | 
 geom            | geometry | 
Indexes:
    "node_primary_key" PRIMARY KEY, btree (node_id)
    "node_gist" gist (geom)
Check constraints:
    "enforce_dims_geom" CHECK (st_ndims(geom) = 2)
    "enforce_geotype_geom" CHECK (geometrytype(geom) = 'POINT'::text OR geom IS NULL)
    "enforce_srid_geom" CHECK (st_srid(geom) = (-1))
Foreign-key constraints:
    "face_exists" FOREIGN KEY (containing_face) REFERENCES urbanarea.face(face_id)
Referenced by:
    TABLE "urbanarea.edge_data" CONSTRAINT "end_node_exists" FOREIGN KEY (end_node) REFERENCES urbanarea.node(node_id)
    TABLE "urbanarea.edge_data" CONSTRAINT "start_node_exists" FOREIGN KEY (start_node) REFERENCES urbanarea.node(node_id)

\d urbanarea.edge_data
                                      Table "urbanarea.edge_data"
       Column        |   Type   |                               Modifiers                               
---------------------+----------+-----------------------------------------------------------------------
 edge_id             | integer  | not null default nextval('urbanarea.edge_data_edge_id_seq'::regclass)
 start_node          | integer  | not null
 end_node            | integer  | not null
 next_left_edge      | integer  | not null
 abs_next_left_edge  | integer  | not null
 next_right_edge     | integer  | not null
 abs_next_right_edge | integer  | not null
 left_face           | integer  | not null
 right_face          | integer  | not null
 geom                | geometry | 
Indexes:
    "edge_data_pkey" PRIMARY KEY, btree (edge_id)
    "edge_gist" gist (geom)
    "edge_left_face_idx" btree (left_face)
    "edge_right_face_idx" btree (right_face)
Check constraints:
    "enforce_dims_geom" CHECK (st_ndims(geom) = 2)
    "enforce_geotype_geom" CHECK (geometrytype(geom) = 'LINESTRING'::text OR geom IS NULL)
    "enforce_srid_geom" CHECK (st_srid(geom) = (-1))
Foreign-key constraints:
    "end_node_exists" FOREIGN KEY (end_node) REFERENCES urbanarea.node(node_id)
    "left_face_exists" FOREIGN KEY (left_face) REFERENCES urbanarea.face(face_id)
    "next_left_edge_exists" FOREIGN KEY (abs_next_left_edge) REFERENCES urbanarea.edge_data(edge_id) DEFERRABLE INITIALLY DEFERRED
    "next_right_edge_exists" FOREIGN KEY (abs_next_right_edge) REFERENCES urbanarea.edge_data(edge_id) DEFERRABLE INITIALLY DEFERRED
    "right_face_exists" FOREIGN KEY (right_face) REFERENCES urbanarea.face(face_id)
    "start_node_exists" FOREIGN KEY (start_node) REFERENCES urbanarea.node(node_id)
Referenced by:
    TABLE "urbanarea.edge_data" CONSTRAINT "next_left_edge_exists" FOREIGN KEY (abs_next_left_edge) REFERENCES urbanarea.edge_data(edge_id) DEFERRABLE INITIALLY DEFERRED
    TABLE "urbanarea.edge_data" CONSTRAINT "next_right_edge_exists" FOREIGN KEY (abs_next_right_edge) REFERENCES urbanarea.edge_data(edge_id) DEFERRABLE INITIALLY DEFERRED

\d urbanarea.face
                                Table "urbanarea.face"
 Column  |   Type   |                            Modifiers                             
---------+----------+------------------------------------------------------------------
 face_id | integer  | not null default nextval('urbanarea.face_face_id_seq'::regclass)
 mbr     | geometry | 
Indexes:
    "face_primary_key" PRIMARY KEY, btree (face_id)
    "face_gist" gist (mbr)
Check constraints:
    "enforce_dims_mbr" CHECK (st_ndims(mbr) = 2)
    "enforce_geotype_mbr" CHECK (geometrytype(mbr) = 'POLYGON'::text OR mbr IS NULL)
    "enforce_srid_mbr" CHECK (st_srid(mbr) = (-1))
Referenced by:
    TABLE "urbanarea.node" CONSTRAINT "face_exists" FOREIGN KEY (containing_face) REFERENCES urbanarea.face(face_id)
    TABLE "urbanarea.edge_data" CONSTRAINT "left_face_exists" FOREIGN KEY (left_face) REFERENCES urbanarea.face(face_id)
    TABLE "urbanarea.edge_data" CONSTRAINT "right_face_exists" FOREIGN KEY (right_face) REFERENCES urbanarea.face(face_id)

Přidání atributu topologie do feature table

select topology.AddTopoGeometryColumn('urbanarea', 'public', 'urbanarea', 'topo', 'POLYGON');

\d urbanarea

...
 topo         | topology.topogeometry | 
...

SELECT * FROM topology.layer;

 topology_id | layer_id | schema_name | table_name | feature_column | feature_type | level | child_id 
-------------+----------+-------------+------------+----------------+--------------+-------+----------
           1 |        2 | public      | urbanarea  | topo           |            3 |     0 |         

Externí odkazy

• State of the art of FOSS4G for topology and network analysis
• PostGIS 2.0 Topology section of manual
• Topogie • Sedm mostů města Královce • Topological modeling