MySQL Manual
11 Spatial Extensions in MySQL
- 11.2 The OpenGIS Geometry Model
- 11.2.1 The Geometry Class Hierarchy
- 11.2.2 Class
Geometry - 11.2.4 Class
Point - 11.2.7 Class
Curve - 11.2.9 Class
LineString - 11.2.12 Class
Surface - 11.2.14 Class
Polygon - 11.2.17 Class
GeometryCollection - 11.2.18 Class
MultiPoint - 11.2.21 Class
MultiCurve - 11.2.23 Class
MultiLineString - 11.2.25 Class
MultiSurface - 11.2.27 Class
MultiPolygon
11.2.14 Class Polygon
A Polygon is a planar Surface representing a multisided
geometry. It is defined by a single exterior boundary and zero or more
interior boundaries, where
each interior boundary defines a hole in the Polygon.
11.2.15 Polygon Examples
-
On a region map,
Polygonobjects could represent forests, districts, etc.
11.2.16 Polygon Assertions
-
The boundary of a
Polygonconsists of a set ofLinearRings (that is,LineStrings that are both simple and closed) that make up its exterior and interior boundaries. -
No two rings in the boundary cross. The rings in the boundary of a
Polygonmay intersect at aPoint, but only as a tangent. -
A
Polygonmay not have cut lines, spikes, or punctures. -
The interior of every
Polygonis a connected point set. -
The exterior of a
Polygonwith one or more holes is not connected. Each hole defines a connected component of the exterior.
In the above assertions, polygons are simple geometries. These assertions make
a Polygon a simple geometry.
