SDO_UTIL.VALIDATE_WKTGEOMETRY

Format

SDO_UTIL.VALIDATE_WKTGEOMETRY(
     geometry  IN CLOB 
     ) RETURN VARCHAR2;

or

SDO_UTIL.VALIDATE_WKTGEOMETRY(
     geometry  IN VARCHAR2 
     ) RETURN VARCHAR2;

Description

Validates the input geometry, which is of type CLOB or VARCHAR2 and in the standard well-known text (WKT) format; returns the string TRUE if the geometry is valid or FALSE if the geometry is not valid.

Parameters

geometry: Geometry in WKT format to be checked for validity.

Usage Notes

Note:

SDO_UTIL.VALIDATE_WKTGEOMETRY function is not supported in Oracle Autonomous Database Serverless deployments.

To be valid, the input geometry must be in the well-known text (WKT) format, as defined by the Open Geospatial Consortium and the International Organization for Standardization (ISO).

This function is patterned after the SQL Multimedia recommendations in ISO 13249-3, Information technology - Database languages - SQL Multimedia and Application Packages - Part 3: Spatial.

To validate a geometry in the well-known binary (WKB) format, use the SDO_UTIL.VALIDATE_WKBGEOMETRY function.

Examples

The following example shows conversion to and from WKB and WKT format, and validation of WKB and WKT geometries. (The example uses the definitions and data from Simple Example: Inserting_ Indexing_ and Querying Spatial Data, specifically the cola_b geometry from the COLA_MARKETS table.)

DECLARE
  wkbgeom BLOB;
  wktgeom CLOB;
  val_result VARCHAR2(5);
  geom_result SDO_GEOMETRY;
  geom SDO_GEOMETRY;
BEGIN
SELECT c.shape INTO geom FROM cola_markets c WHERE c.name = 'cola_b';
 
-- To WBT/WKT geometry
wkbgeom := SDO_UTIL.TO_WKBGEOMETRY(geom);
wktgeom := SDO_UTIL.TO_WKTGEOMETRY(geom);
DBMS_OUTPUT.PUT_LINE('To WKT geometry result = ' || TO_CHAR(wktgeom));
 
-- From WBT/WKT geometry
geom_result := SDO_UTIL.FROM_WKBGEOMETRY(wkbgeom);
geom_result := SDO_UTIL.FROM_WKTGEOMETRY(wktgeom);
 
-- Validate WBT/WKT geometry
val_result := SDO_UTIL.VALIDATE_WKBGEOMETRY(wkbgeom);
DBMS_OUTPUT.PUT_LINE('WKB validation result = ' || val_result);
val_result := SDO_UTIL.VALIDATE_WKTGEOMETRY(wktgeom);
DBMS_OUTPUT.PUT_LINE('WKT validation result = ' || val_result);
 
END;/
 
To WKT geometry result = POLYGON ((5.0 1.0, 8.0 1.0, 8.0 6.0, 5.0 7.0, 5.0 1.0))
WKB validation result = TRUE                                                    
WKT validation result = TRUE