(mysql.info) functions-that-test-spatial-relationships-between-geometries

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(mysql.info) relations-on-geometry-mbr

(mysql.info) analysing-spatial-information

 
 16.5.6 Functions That Test Spatial Relationships Between Geometries
 -------------------------------------------------------------------
 
 The OpenGIS specification defines the following functions. They test
 the relationship between two geometry values `g1' and `g2'.
 
 Currently, MySQL does not implement these functions according to the
 specification. Those that are implemented return the same result as the
 corresponding MBR-based functions. This includes functions in the
 following list other than `Distance()' and `Related()'.
 
 These functions may be implemented in future releases with full support
 for spatial analysis, not just MBR-based support.
 
 The return values 1 and 0 indicate true and false, respectively.
 
    * `Contains(G1,G2)'
 
      Returns 1 or 0 to indicate whether G1 completely contains G2.
 
    * `Crosses(G1,G2)'
 
      Returns 1 if G1 spatially crosses G2. Returns `NULL' if `g1' is a
      `Polygon' or a `MultiPolygon', or if G2 is a `Point' or a
      `MultiPoint'. Otherwise, returns 0.
 
      The term _spatially crosses_ denotes a spatial relation between
      two given geometries that has the following properties:
 
         * The two geometries intersect
 
         * Their intersection results in a geometry that has a dimension
           that is one less than the maximum dimension of the two given
           geometries
 
         * Their intersection is not equal to either of the two given
           geometries
 
    * `Disjoint(G1,G2)'
 
      Returns 1 or 0 to indicate whether G1 is spatially disjoint from
      (does not intersect) G2.
 
    * `Distance(G1,G2)'
 
      Returns as a double-precision number the shortest distance between
      any two points in the two geometries.
 
    * `Equals(G1,G2)'
 
      Returns 1 or 0 to indicate whether G1 is spatially equal to G2.
 
    * `Intersects(G1,G2)'
 
      Returns 1 or 0 to indicate whether G1 spatially intersects G2.
 
    * `Overlaps(G1,G2)'
 
      Returns 1 or 0 to indicate whether G1 spatially overlaps G2. The
      term _spatially overlaps_ is used if two geometries intersect and
      their intersection results in a geometry of the same dimension but
      not equal to either of the given geometries.
 
    * `Related(G1,G2,PATTERN_MATRIX)'
 
      Returns 1 or 0 to indicate whether the spatial relationship
      specified by PATTERN_MATRIX exists between G1 and G2. Returns -1
      if the arguments are `NULL'. The pattern matrix is a string. Its
      specification will be noted here if this function is implemented.
 
    * `Touches(G1,G2)'
 
      Returns 1 or 0 to indicate whether G1 spatially touches G2. Two
      geometries _spatially touch_ if the interiors of the geometries do
      not intersect, but the boundary of one of the geometries
      intersects either the boundary or the interior of the other.
 
    * `Within(G1,G2)'
 
      Returns 1 or 0 to indicate whether G1 is spatially within G2.
 

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(mysql.info) relations-on-geometry-mbr

(mysql.info) analysing-spatial-information