描述

Calculates the length or perimeter of a geometry on a spheroid. This is useful if the coordinates of the geometry are in longitude/latitude and a length is desired without reprojection. The spheroid is specified by a text value as follows:

例如：

可用性：1.2.2

更改：2.2.0 在之前的版本中，这称为 ST_Length_Spheroid 并具有别名 ST_3DLength_Spheroid

该函数支持 3d 并且不会丢失 z-index。

示例

SELECT ST_LengthSpheroid(
                                  geometry_column,
                                  'SPHEROID["GRS_1980",6378137,298.257222101]'
                      )
                          FROM geometry_table;

SELECT ST_LengthSpheroid(geom, sph_m ) As tot_len,
ST_LengthSpheroid(ST_GeometryN(geom,1), sph_m) As len_line1,
ST_LengthSpheroid(ST_GeometryN(geom,2), sph_m) As len_line2
                          FROM (SELECT ST_GeomFromText('MULTILINESTRING((-118.584 38.374,-118.583 38.5),
        (-71.05957 42.3589 , -71.061 43))') As geom,
CAST('SPHEROID["GRS_1980",6378137,298.257222101]' As spheroid) As sph_m)  as foo;

tot_len      |    len_line1     |    len_line2
------------------+------------------+------------------
 85204.52077117894 | 13986.87252824332 | 71217.64824293563

This example uses 3D input.

SELECT ST_LengthSpheroid(geom, sph_m ) As tot_len,
ST_LengthSpheroid(ST_GeometryN(geom,1), sph_m) As len_line1,
ST_LengthSpheroid(ST_GeometryN(geom,2), sph_m) As len_line2
                          FROM (SELECT ST_GeomFromEWKT('MULTILINESTRING((-118.584 38.374 20,-118.583 38.5 30),
        (-71.05957 42.3589 75, -71.061 43 90))') As geom,
CAST('SPHEROID["GRS_1980",6378137,298.257222101]' As spheroid) As sph_m)  as foo;

tot_len      |    len_line1    |    len_line2
------------------+-----------------+------------------
 85204.52592562366 | 13986.876103023424 | 71217.64982260024

相关信息

ST_GeometryN, ST_Length