ST_CurveToLine method

Returns the ST_LineString interpolation of an ST_Curve value.

Syntax

curve-expression.ST_CurveToLine()

Returns

ST_LineString Returns the ST_LineString interpolation of curve-expression.
The spatial reference system identifier of the result is the same as the spatial reference system of the curve-expression.

If curve-expression is empty, the ST_CurveToLine method returns an empty set of type ST_LineString. Otherwise, ST_CurveToLine returns a linestring containing any linestrings in curve-expression combined with the interpolation of any circularstrings in curve-expression.

Note

By default, ST_CurveToLine 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 (0 7, 0 4, 4 4) (a copy of the original linestring).

SELECT TREAT( Shape AS ST_Curve ).ST_CurveToLine()
FROM SpatialShapes WHERE ShapeID = 5

The following example returns the result LineString (0 0, 5 10) (the compound curve converted to an equivalent linestring).

SELECT NEW ST_CompoundCurve( 'CompoundCurve((0 0, 5 10))' ).ST_CurveToLine()

The following returns an interpolated linestring which approximates the original circularstring.

SELECT TREAT( Shape AS ST_Curve ).ST_CurveToLine()
FROM SpatialShapes WHERE ShapeID = 19

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