User's Guide and Reference

ST_Perimeter

ST_Perimeter returns the perimeter of an ST_Surface.

Syntax


db2gse.ST_Perimeter(s db2gse.ST_Surface)
db2gse.ST_Perimeter(ms db2gse.ST_MultiSurface)

Return type


Double

Examples

An ecologist studying shoreline birds needs to determine the shoreline for the lakes within a particular area. The lakes are stored as multipolygons in the WATERBODIES table that was created with the following CREATE TABLE statement.

CREATE TABLE WATERBODIES (wbid  integer,
 	                       waterbody  db2gse.ST_MultiPolygon);

In the following SELECT statement, the ST_Perimeter function returns the perimeter surrounding each body of water, while the SUM function aggregates the perimeters to return their total.

SELECT SUM(db2gse.ST_Perimeter(waterbody))
FROM waterbodies;


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