Defines the format of geometry data when using character data to construct new ST_Geometry instances or transfer ST_Geometry values to and from client applications.
Format
- point
-
POINT point_spec
- linestring
-
LINESTRING linestring_spec
- polygon
-
POLYGON polygon_spec
- multipoint
-
MULTIPOINT { EMPTY | ( point_spec [,...] ) }
- multilinestring
-
MULTILINESTRING { EMPTY | ( linestring_spec [,...] ) }
- multipolygon
-
MULTIPOLYGON { EMPTY | ( polygon_spec [,...] ) }
- geometrycollection
-
GEOMETRYCOLLECTION { EMPTY | ( geometry_collection_item [,...] ) }
- geosequence
-
GEOSEQUENCE { EMPTY | ( ( x-y_pair [,...] ), ( ts [,...] ), ( linkID [,...] ), ( count, uf [,...] ) ) }
- point_spec
-
{ EMPTY | ( x-y_pair_opt_z ) }
- linestring_spec
-
{ EMPTY | ( x-y_pair_opt_z [,...] ) }
- polygon_spec
-
{ EMPTY | ( linestring_spec [,...] ) }
- geometry_collection_item
-
{ point | linestring | polygon | multipoint | multilinestring | multipolygon | geometry_collection | geosequence }
- x-y_pair
-
x y
- x-y_pair_opt_z
-
x y [ z ]
- EMPTY
- The empty set.
- x
- A numeric value that represents the x coordinate of a point.
- y
- A numeric value that represents the y coordinate of a point.
- z
- A numeric value that represents the z coordinate of a point in 3D space.
- ts
- A timestamp value with the following format:
yyyy-mm-dd hh:mi:ss.ms
- linkID
- A NUMERIC(18,0) value for the ID of the link on the road network for a point in the geosequence.
- count
- An integer value that represents the number of uf elements for each point in the geosequence.
- uf
- A user field that represents a FLOAT value to associate with a point. For example, certain tracking systems may associate velocity, direction, and acceleration values with each point.
Usage Notes
Teradata Database implements transform functionality that, by default, allows importing and exporting an ST_Geometry type to and from the server as a CLOB in WKT format. This means that a client application can use a CLOB to insert a value into an ST_Geometry column, provided the CLOB uses the WKT format of one of the geospatial subtypes that ST_Geometry can represent. Similarly, when a client application submits a query that selects data from an ST_Geometry column, by default, Teradata Database exports the type as a CLOB using the WKT format of the geometry that the ST_Geometry column represents.
Teradata also provides other transforms for the ST_Geometry type that allow for the import and export of geospatial data as other types and formats. For more information, see ST_Geometry Type Transforms
Examples: WKT Format for Geospatial Data
Consider the following table:
CREATE TABLE sample_shapes (skey INTEGER, shape ST_Geometry);
Here are some examples that show how to insert geometry values using WKT representation:
INSERT INTO sample_shapes VALUES (1001, 'POINT(10 20)'); INSERT INTO sample_shapes VALUES (1002, 'POINT EMPTY'); INSERT INTO sample_shapes VALUES (1003, 'LINESTRING(1 1, 2 2, 3 3, 4 4)'); INSERT INTO sample_shapes VALUES (1004, 'LINESTRING EMPTY'); INSERT INTO sample_shapes VALUES (1005, 'POLYGON((0 0, 0 20, 20 20, 20 0, 0 0), (5 5, 5 10, 10 10, 10 5, 5 5))'); INSERT INTO sample_shapes VALUES (1006, 'MULTIPOINT((1 1), (1 3), (6 3), (10 5), (20 1))'); INSERT INTO sample_shapes VALUES (1007, 'MULTILINESTRING((1 1, 1 3, 6 3), (10 5, 20 1))'); INSERT INTO sample_shapes VALUES (1008, 'MULTIPOLYGON(((1 1, 1 3, 6 3, 6 0, 1 1)), ((10 5, 10 10, 20 10, 20 5, 10 5)))'); INSERT INTO sample_shapes VALUES (1009, 'GEOMETRYCOLLECTION( POINT(10 10), POINT(30 30), LINESTRING(15 15, 20 20))'); INSERT INTO sample_shapes VALUES (1010, 'GEOSEQUENCE( (10 20, 30 40, 50 60), (2007-08-22 12:05:23.56, 2007-08-22 12:08:25.14, 2007-08-22 12:11:41.52), (1, 2, 3), (2, 10, 12, 11, 18, 21, 19) )' ); INSERT INTO sample_shapes VALUES (1011, 'GEOSEQUENCE( (10 20, 30 40, 50 60), (2008-03-17 10:34:03.53, 2008-03-17 10:38:25.21, 2008-03-17 10:41:41.48), (1, 2, 3), (0))'); SELECT * FROM sample_shapes ORDER BY skey;