ST_NumPoints — Return the number of points in an ST_LineString or ST_CircularString value.
integer ST_NumPoints(geometry  g1);
Return the number of points in an ST_LineString or ST_CircularString value. Prior to 1.4 only works with Linestrings as the specs state. From 1.4 forward this is an alias for ST_NPoints which returns number of vertexes for not just line strings. Consider using ST_NPoints instead which is multi-purpose and works with many geometry types.
 This method implements the OpenGIS Simple Features
 Implementation Specification for SQL 1.1.
 This method implements the OpenGIS Simple Features
 Implementation Specification for SQL 1.1.
 This method implements the SQL/MM specification. SQL-MM 3: 7.2.4
 This method implements the SQL/MM specification. SQL-MM 3: 7.2.4