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st_length function

Applies to: check marked yes Databricks Runtime 17.1 and above

Important

This feature is in Public Preview.

Returns the length of the input GEOGRAPHY or GEOMETRY value.

Syntax

st_length ( geoExpr )

Arguments

  • geoExpr: A GEOGRAPHY or GEOMETRY value.

Returns

A value of type DOUBLE, representing the length of the input GEOGRAPHY or GEOMETRY value.

If the input is a GEOGRAPHY value, the function returns the 2D geodesic length of the linear part of the GEOGRAPHY value. Specifically, the function returns the geodesic length for linestrings, and the sum of the lengths of the linestrings in a multilinestring. For non-linear geographies (points, polygons, multipoints, and multipolygons) 0 is returned, whereas for geometry collections the function returns the sum of the lengths of the elements in the collection. The result is computed by performing the inverse geodesic calculation assuming the WGS84 ellipsoid. The units of the result is meters.

If the input is a GEOMETRY value, the function returns the 2D Cartesian length of the linear part of the GEOMETRY value. Specifically, the function returns the 2D Cartesian length for linestrings, and the sum of the lengths of the linestrings in a multilinestring. For non-linear geometries (points, polygons, multipoints, and multipolygons) 0 is returned, whereas for geometry collections it returns the sum of the lengths of the elements in the collection. The units of the result are those of the spatial reference system of the input GEOMETRY value.

The function returns NULL if any of the inputs is NULL.

Examples

-- Returns the length of a 2D Cartesian linestring.
> SELECT round(st_length(st_geomfromtext('LINESTRING(10 34,44 57,30 24)')), 8)
  76.89564816