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Spec-Zone .ru
спецификации, руководства, описания, API
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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.
MySQL provides a number of functions that take as arguments 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.
GeomCollFromText(, wkt[,srid])GeometryCollectionFromText(wkt[,srid])
Constructs a GEOMETRYCOLLECTION value using its WKT representation
and SRID.
GeomFromText(, wkt[,srid])GeometryFromText(wkt[,srid])
Constructs a geometry value of any type using its WKT representation and SRID.
LineFromText(, wkt[,srid])LineStringFromText(wkt[,srid])
Constructs a LINESTRING value using its WKT representation and
SRID.
MLineFromText(, wkt[,srid])MultiLineStringFromText(wkt[,srid])
Constructs a MULTILINESTRING value using its WKT representation and
SRID.
MPointFromText(, wkt[,srid])MultiPointFromText(wkt[,srid])
Constructs a MULTIPOINT value using its WKT representation and
SRID.
MPolyFromText(, wkt[,srid])MultiPolygonFromText(wkt[,srid])
Constructs a MULTIPOLYGON value using its WKT representation and
SRID.
Constructs a POINT value using its WKT representation and SRID.
PolyFromText(, wkt[,srid])PolygonFromText(wkt[,srid])
Constructs a POLYGON value using its WKT representation and SRID.
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.
Constructs a MultiPolygon value from a MultiLineString
value in WKT format containing an arbitrary collection of closed LineString
values.
Constructs a Polygon value from a MultiLineString
value in WKT format containing an arbitrary collection of closed LineString
values.
MySQL provides a number of functions that take as arguments a BLOB containing a Well-Known Binary representation and, optionally, a spatial
reference system identifier (SRID). They return the corresponding geometry.
These functions also accept geometry objects for compatibility with the return value of the functions in Section 12.18.4.2.3, "Creating Geometry Values Using MySQL-Specific Functions". Thus, those functions may be used to provide the first argument to the functions in this section.
GeomCollFromWKB(, wkb[,srid])GeometryCollectionFromWKB(wkb[,srid])
Constructs a GEOMETRYCOLLECTION value using its WKB representation
and SRID.
GeomFromWKB(, wkb[,srid])GeometryFromWKB(wkb[,srid])
Constructs a geometry value of any type using its WKB representation and SRID.
LineFromWKB(, wkb[,srid])LineStringFromWKB(wkb[,srid])
Constructs a LINESTRING value using its WKB representation and
SRID.
MLineFromWKB(, wkb[,srid])MultiLineStringFromWKB(wkb[,srid])
Constructs a MULTILINESTRING value using its WKB representation and
SRID.
MPointFromWKB(, wkb[,srid])MultiPointFromWKB(wkb[,srid])
Constructs a MULTIPOINT value using its WKB representation and
SRID.
MPolyFromWKB(, wkb[,srid])MultiPolygonFromWKB(wkb[,srid])
Constructs a MULTIPOLYGON value using its WKB representation and
SRID.
Constructs a POINT value using its WKB representation and SRID.
PolyFromWKB(, wkb[,srid])PolygonFromWKB(wkb[,srid])
Constructs a POLYGON value using its WKB representation and SRID.
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:
Constructs a MultiPolygon value from a MultiLineString
value in WKB format containing an arbitrary collection of closed LineString
values.
Constructs a Polygon value from a MultiLineString
value in WKB format containing an arbitrary collection of closed LineString
values.
MySQL provides a set of useful nonstandard functions for creating geometry values. The functions described in this section are MySQL extensions to the OpenGIS specification.
These functions produce geometry objects from either WKB values or geometry objects as arguments. If any
argument is not a proper WKB or geometry representation of the proper object type, the return value is NULL.
For example, you can insert the geometry return value from Point() directly into a Point column:
INSERT INTO t1 (pt_col) VALUES(Point(1,2));
Constructs a GeometryCollection.
Constructs a LineString value from a number of Point or WKB Point arguments. If the
number of arguments is less than two, the return value is NULL.
Constructs a MultiLineString value using LineString
or WKB LineString arguments.
Constructs a MultiPoint value using Point or WKB Point arguments.
Constructs a MultiPolygon value from a set of Polygon or WKB Polygon arguments.
Constructs a Point using its coordinates.
Constructs a Polygon value from a number of LineString
or WKB LineString arguments. If any argument does not represent a
LinearRing (that is, not a closed and simple LineString),
the return value is NULL.