Description
The ST_Distance function calculates and returns the distance between two
geometries.
Syntax
ST_Distance(WritableGeometry geometry1, WritableGeometry geometry2, String linearUnits, [String computationType])
Parameters
| Parameter |
Type |
Description |
|
geometry1
|
WritableGeometry |
The first instance of a WritableGeometry. |
|
geometry2
|
WritableGeometry |
The second instance of a WritableGeometry. |
|
linearUnits
|
String |
The desired return unit type. For valid values, see Linear Units. |
|
computationType
|
String |
Optional. Indicates the logic to be used to interpret geometry coordinates. The
computation type is based on the coordinate system of the geometry being operated
on:
- For geographic (long/lat) coordinate systems: Valid type =
SPHERICAL (default)
- For projected coordinate systems: Valid types =
CARTESIAN,
SPHERICAL (default)
- For engineering coordinate systems: Valid type =
CARTESIAN
(default)
- CARTESIAN
- The geometry coordinates are interpreted using cartesian logic.
- SPHERICAL
- The geometry coordinates are interpreted using spherical logic.
|
Linear Units
The following table lists the valid values for unit type.
| Value |
Description |
| mi |
miles |
| km |
kilometers |
| in |
inches |
| ft |
feet |
| yd |
yards |
| mm |
millimeters |
| cm |
centimeters |
| m |
meters |
| survey ft |
US Survey feet |
| nmi |
nautical miles |
Return Values
| Return Type |
Description |
| Double |
The distance between the two geometries. Geometries that intersect are at
distance zero from each other. Distance is always non-negative. |
Examples
SELECT ST_Distance(ST_GeomFromWkt(t.geometry,'epsg:4267'),
ST_GeomFromWkt(t.geometry2,'epsg:4267'), 'm', 'SPHERICAL') FROM table t;
SELECT ST_Distance(ST_GeomFromWkt(t.geometry,'epsg:4267'),
ST_GeomFromWkt(t.geometry2,'epsg:4267'), 'm') FROM table t;