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11.13.4.3 Creating Spatial Columns »
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11.13.4.2. Creating Spatial Values

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11.13.4.2.1. Creating Geometry Values Using WKT Functions
11.13.4.2.2. Creating Geometry Values Using WKB Functions
11.13.4.2.3. Creating Geometry Values Using MySQL-Specific Functions

This section describes how to create spatial values using Well-Known Text and Well-Known Binary functions that are defined in the OpenGIS standard, and using MySQL-specific functions.

11.13.4.2.1. Creating Geometry Values Using WKT Functions

MySQL provides a number of functions that take as input parameters a Well-Known Text representation and, optionally, a spatial reference system identifier (SRID). They return the corresponding geometry.

GeomFromText() accepts a WKT of any geometry type as its first argument. An implementation also provides type-specific construction functions for construction of geometry values of each geometry type.

The OpenGIS specification also defines the following optional functions, which MySQL does not implement. These functions construct Polygon or MultiPolygon values based on the WKT representation of a collection of rings or closed LineString values. These values may intersect.

  • BdMPolyFromText(wkt,srid)

    Constructs a MultiPolygon value from a MultiLineString value in WKT format containing an arbitrary collection of closed LineString values.

  • BdPolyFromText(wkt,srid)

    Constructs a Polygon value from a MultiLineString value in WKT format containing an arbitrary collection of closed LineString values.

11.13.4.2.2. Creating Geometry Values Using WKB Functions

MySQL provides a number of functions that take as input parameters a BLOB containing a Well-Known Binary representation and, optionally, a spatial reference system identifier (SRID). They return the corresponding geometry.

GeomFromWKB() accepts a WKB of any geometry type as its first argument. An implementation also provides type-specific construction functions for construction of geometry values of each geometry type.

The OpenGIS specification also describes optional functions for constructing Polygon or MultiPolygon values based on the WKB representation of a collection of rings or closed LineString values. These values may intersect. MySQL does not implement these functions:

  • BdMPolyFromWKB(wkb,srid)

    Constructs a MultiPolygon value from a MultiLineString value in WKB format containing an arbitrary collection of closed LineString values.

  • BdPolyFromWKB(wkb,srid)

    Constructs a Polygon value from a MultiLineString value in WKB format containing an arbitrary collection of closed LineString values.

11.13.4.2.3. Creating Geometry Values Using MySQL-Specific Functions

MySQL provides a set of useful non-standard functions for creating geometry WKB representations. The functions described in this section are MySQL extensions to the OpenGIS specification. The results of these functions are BLOB values containing WKB representations of geometry values with no SRID. The results of these functions can be substituted as the first argument for any function in the GeomFromWKB() function family.

  • GeometryCollection(g1,g2,...)

    Constructs a WKB GeometryCollection. If any argument is not a well-formed WKB representation of a geometry, the return value is NULL.

  • LineString(pt1,pt2,...)

    Constructs a WKB LineString value from a number of WKB Point arguments. If any argument is not a WKB Point, the return value is NULL. If the number of Point arguments is less than two, the return value is NULL.

  • MultiLineString(ls1,ls2,...)

    Constructs a WKB MultiLineString value using WKB LineString arguments. If any argument is not a WKB LineString, the return value is NULL.

  • MultiPoint(pt1,pt2,...)

    Constructs a WKB MultiPoint value using WKB Point arguments. If any argument is not a WKB Point, the return value is NULL.

  • MultiPolygon(poly1,poly2,...)

    Constructs a WKB MultiPolygon value from a set of WKB Polygon arguments. If any argument is not a WKB Polygon, the return value is NULL.

  • Point(x,y)

    Constructs a WKB Point using its coordinates.

  • Polygon(ls1,ls2,...)

    Constructs a WKB Polygon value from a number of WKB LineString arguments. If any argument does not represent the WKB of a LinearRing (that is, not a closed and simple LineString) the return value is NULL.