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geo_line_length()

  • 项目

Applies to: ✅ Microsoft Fabric ✅ Azure Data Explorer ✅ Azure Monitor ✅ Microsoft Sentinel

Calculates the total length of a line or a multiline on Earth.

Syntax

geo_line_length(lineString)

Learn more about syntax conventions.

Parameters

Name Type Required Description
lineString dynamic ✔️ A LineString or MultiLineString in the GeoJSON format.

Returns

The total length of a line or a multiline, in meters, on Earth. If the line or multiline is invalid, the query will produce a null result.

Note

  • The geospatial coordinates are interpreted as represented by the WGS-84 coordinate reference system.
  • The geodetic datum used to measure distance on Earth is a sphere. Line edges are geodesics on the sphere.
  • If input line edges are straight cartesian lines, consider using geo_line_densify() in order to convert planar edges to geodesics.
  • If input is a multiline and contains more than one line, the result will be total length of lines union.

LineString definition and constraints

dynamic({"type": "LineString","coordinates": [[lng_1,lat_1], [lng_2,lat_2], ..., [lng_N,lat_N]]})

dynamic({"type": "MultiLineString","coordinates": [[line_1, line_2, ..., line_N]]})

  • LineString coordinates array must contain at least two entries.
  • Coordinates [longitude, latitude] must be valid where longitude is a real number in the range [-180, +180] and latitude is a real number in the range [-90, +90].
  • Edge length must be less than 180 degrees. The shortest edge between the two vertices will be chosen.

Examples

The following example calculates the total line length, in meters.

let line = dynamic({"type":"LineString","coordinates":[[-73.95807266235352,40.800426144169315],[-73.94966125488281,40.79691751000055],[-73.97317886352539,40.764486356930334]]});
print length = geo_line_length(line)

Output

length
4922.48016992081

The following example calculates total multiline length, in meters.

let line = dynamic({"type":"MultiLineString","coordinates":[[[-73.95798683166502,40.800556090021466],[-73.98193359375,40.76819171855746]],[[-73.94940376281738,40.79691751000055],[-73.97317886352539,40.76435634049001]]]});
print length = geo_line_length(line)

Output

length
8262.24339753741

The following example returns True because of the invalid line.

print is_bad_line = isnull(geo_line_length(dynamic({"type":"LineString","coordinates":[[1, 1]]})))

Output

is_bad_line
True