(mysql.info) polygon-property-functions

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(mysql.info) multipolygon-property-functions

 
 16.5.2.5 `Polygon' Functions
 ............................
 
    * `Area(POLY)'
 
      Returns as a double-precision number the area of the `Polygon'
      value POLY, as measured in its spatial reference system.
 
           mysql> SET @poly = 'Polygon((0 0,0 3,3 0,0 0),(1 1,1 2,2 1,1 1))';
           mysql> SELECT Area(GeomFromText(@poly));
           +---------------------------+
           | Area(GeomFromText(@poly)) |
           +---------------------------+
           |                         4 |
           +---------------------------+
 
    * `ExteriorRing(POLY)'
 
      Returns the exterior ring of the `Polygon' value POLY as a
      `LineString'.
 
           mysql> SET @poly =
               -> 'Polygon((0 0,0 3,3 3,3 0,0 0),(1 1,1 2,2 2,2 1,1 1))';
           mysql> SELECT AsText(ExteriorRing(GeomFromText(@poly)));
           +-------------------------------------------+
           | AsText(ExteriorRing(GeomFromText(@poly))) |
           +-------------------------------------------+
           | LINESTRING(0 0,0 3,3 3,3 0,0 0)           |
           +-------------------------------------------+
 
    * `InteriorRingN(POLY,N)'
 
      Returns the N-th interior ring for the `Polygon' value POLY as a
      `LineString'. Rings are numbered beginning with 1.
 
           mysql> SET @poly =
               -> 'Polygon((0 0,0 3,3 3,3 0,0 0),(1 1,1 2,2 2,2 1,1 1))';
           mysql> SELECT AsText(InteriorRingN(GeomFromText(@poly),1));
           +----------------------------------------------+
           | AsText(InteriorRingN(GeomFromText(@poly),1)) |
           +----------------------------------------------+
           | LINESTRING(1 1,1 2,2 2,2 1,1 1)              |
           +----------------------------------------------+
 
    * `NumInteriorRings(POLY)'
 
      Returns the number of interior rings in the `Polygon' value POLY.
 
           mysql> SET @poly =
               -> 'Polygon((0 0,0 3,3 3,3 0,0 0),(1 1,1 2,2 2,2 1,1 1))';
           mysql> SELECT NumInteriorRings(GeomFromText(@poly));
           +---------------------------------------+
           | NumInteriorRings(GeomFromText(@poly)) |
           +---------------------------------------+
           |                                     1 |
           +---------------------------------------+
 

Info Catalog

(mysql.info) multilinestring-property-functions

(mysql.info) geometry-property-functions

(mysql.info) multipolygon-property-functions