ST_SnapToGrid(DOUBLE) method for type ST

ST_SnapToGrid(DOUBLE) method for type ST_Geometry

Returns a copy of the geometry with all points snapped to the specified grid.

Syntax

geometry-expression.ST_SnapToGrid(cell-size)

Parameters

Name	Type	Description
cell-size	DOUBLE	The cell size for the grid.

Returns

ST_Geometry Returns the geometry with all points snapped to the grid.
The spatial reference system identifier of the result is the same as the spatial reference system of the geometry-expression.

Remarks

The ST_SnapToGrid method can be used to reduce the precision of data by snapping all points in a geometry to a grid defined by the origin and cell size.

The X and Y coordinates are snapped to the grid; any Z and M values are unchanged.

Note

Reducing precision may cause the resulting geometry to have different properties. For example, it may cause a simple linestring to cross itself, or it may generate an invalid geometry.

Note

Each spatial reference system defines a grid that all geometries are automatically snapped to. You can not store more precision than this predefined grid.

Note

By default, ST_SnapToGrid uses the original format for a geometry, if it is available. Otherwise, the internal format is used. For more information about internal and original formats, see STORAGE FORMAT clause, CREATE SPATIAL REFERENCE SYSTEM statement.

Standards and compatibility

Example

The following example returns the result LineString (1.536133 6.439453, 2.173828 6.100586).

SELECT NEW ST_LineString( 'LineString( 1.5358 6.4391, 2.17401 6.10018 )' )
              .ST_SnapToGrid( 0.001 )

Each X and Y coordinate is shifted to the closest grid point using a grid size of approximately 0.001. The actual grid size used is not exactly the grid size specified.

Discuter à propos de cette page dans DocCommentXchange.

ST_SnapToGrid(DOUBLE) method for type ST_Geometry

Syntax

Parameters

Returns

Remarks

Note

Note

Note

See also

Standards and compatibility

Example