Spatial Measurement - Ocient Documentation

spatial measurement functions can perform basic calculations on geospatial data, such as measuring the distance between two POINT objects or the area of a POLYGON object.

ST_AREA

Returns the area of the specified geospatial object in the specified unit of measurement. Syntax

SQL

ST_AREA(geo [, units] [, use_spheroid ] )

Argument	Data Type	Description
`geo`	`POINT`, `LINESTRING`, or `POLYGON`	A geospatial object to be measured in the specified measurement unit.
`units`	`STRING`	Optional. Supported units are `'FEET'`, `'KILOMETERS'`, `'MILES'`, and `'METERS'`. The default value is `'METERS'`.
`use_spheroid`	`BOOLEAN`	Optional. If you set this value to `TRUE`, this function uses a spheroid model instead of a spherical model. Defaults to `FALSE`.

Example

SQL

SELECT ST_AREA(
        ST_POLYGON(ST_LINESTRING('LINESTRING(2 3, 2 4, 4 2, 2 3)')),
        'MILES');

Output: 196932665.2369081

ST_ANGLE

Calculates the angle between two lines. The lines are represented by three POINT values, including one point for each line (a, b), and a third point (c) representing the vertex where they intersect. The function calculates the spherical angle as formed by the two great circles defined by (a, c) and (b, c). ST_ANGLE returns the value in radians, in the range [0, 2pi], excluding the value 2pi. If either a or b is the same or exactly antipodal to c, the function returns NULL. If any argument is NULL, the function returns NULL. Syntax

SQL

ST_ANGLE(endpoint_a, vertex_c, endpoint_b)

Argument	Data Type	Description
`endpoint_a`	`POINT`	A `POINT` that represents an endpoint for a line between its position and the `vertex_c` value.
`vertex_c`	`POINT`	A `POINT` that represents the intersection between two lines. The lines comprise the endpoints between `endpoint_a` and `vertex_c`, and `endpoint_b` and `vertex_c`.
`endpoint_b`	`POINT`	A `POINT` that represents an endpoint for a line between its position and the `vertex_c` value.

Example

SQL

SELECT ST_ANGLE(ST_POINT(1,0), ST_POINT(0,0), ST_POINT(1,1));

Output: 5.49778714378213

ST_AZIMUTH

Returns the azimuth of the line from point1 to point2 in radians. Returns NULL if either of the points are empty. Returns 0 if both of the points are the same. Syntax

SQL

ST_AZIMUTH(point1, point2)

Argument	Data Type	Description
`point1`	`POINT`	An endpoint for a line to be calculated for its azimuth value.
`point2`	`POINT`	An endpoint for a line to be calculated for its azimuth value.

Example

SQL

SELECT ST_AZIMUTH(ST_POINT(1,1), ST_POINT(2,2));

Output: 0.785398163397448

ST_DISTANCE

Returns the minimum distance between the specified arguments. The ST_DISTANCE function returns the minimum distance in the specified unit of measurement. The use_spheroid optional argument enables the computation to use a spheroid model rather than a spherical one. Syntax

SQL

ST_DISTANCE(geo1, geo2 [, units] [, use_spheroid] )

Argument	Data Type	Description
`geo1`	`POINT`, `LINESTRING`, or `POLYGON`	A geospatial object to be measured for its minimum distance to `geo2`.
`geo2`	`POINT`, `LINESTRING`, or `POLYGON`	A geospatial object to be measured for its minimum distance to `geo1`.
`units`	`STRING`	Optional. Supported units include `'FEET'`, `'KILOMETERS'`, `'MILES'`, and `'METERS'`. If you do not specify this argument, the value defaults to `'METERS'`.
`use_spheroid`	`BOOLEAN`	Optional. If you set this value to `TRUE`, this function uses a spheroid model instead of a spherical model. Defaults to `FALSE`.

Example

SQL

SELECT ST_DISTANCE(
        ST_LINESTRING('LINESTRING(2 3, 2 4)'),
        ST_LINESTRING('LINESTRING(1 2, 1 4, 1 5)'),
        'METERS',
        true);

Output: 111050.10339481

To use ST_DISTANCE as a spatiotemporal function to calculate the minimum simultaneous distance between two linestring-timestamp array pairs, see the ST_DISTANCE function in Spatiotemporal Measurement.

ST_DISTANCESPHERE

Returns the minimum distance between the specified arguments using a spherical computation. This function is identical to ST_DISTANCE with the use_spheroid argument set to FALSE.

SQL

ST_DISTANCESPHERE(geo1, geo2 [, units] )

See ST_DISTANCE for usage example.

ST_DISTANCESPHEROID

Returns the minimum distance between the specified arguments using a spheroid computation. This function is identical to ST_DISTANCE with the use_spheroid argument set to TRUE.

SQL

ST_DISTANCESPHEROID(geo1, geo2 [, units] )

See ST_DISTANCE for usage example.

ST_EUCLIDEANDISTANCE3D

Returns the minimum distance between two geospatial points with altitude values. The distance represents the length of a Euclidean line between the points. Syntax

SQL

ST_EUCLIDEANDISTANCE3D(point1, altitude1, point2, altitude2 [, units] )

Argument	Data Type	Description
`point1`	`POINT`	A geospatial point that represents a Euclidean line with `point2`.
`altitude1`	`DOUBLE`	Distance from the surface of the Earth for `point1`. This argument uses meters, unless you specify a different unit of measurement with the `units` argument.
`point2`	`POINT`	A geospatial point that represents a Euclidean line with `point1`.
`altitude2`	`DOUBLE`	Distance from the surface of the Earth for `point2`. This argument uses meters, unless you specify a different unit of measurement with the `units` argument.
`units`	`VARCHAR`	Optional. This argument specifies the unit of measurement for the distance input arguments and the function output. Supported units are `'FEET'`, `'KILOMETERS'`, `'MILES'`, and `'METERS'`. The default value is `'METERS'`.

Example

SQL

SELECT ST_EUCLIDEANDISTANCE3D(
    ST_POINT(0,0),1000.0,
	ST_POINT(0,1),1000.0,
	'METERS');

Output: 111211.09372321835

ST_HAUSDORFFDISTANCE

Returns the Hausdorff distance between two geographies in a specified measurement. If any argument is NULL or empty, the function returns NULL. The two geographies can be POINT, LINESTRING, or POLYGON values. The system promotes these geographies to filled polygons. Behavior is undefined if the resulting polygons are not convex. Syntax

SQL

ST_HAUSDORFFDISTANCE(geo1, geo2 [, units] [, use_spheroid] )

Argument	Data Type	Description
`geo1`	`POINT`, `LINESTRING`, or `POLYGON`	A geospatial object to be measured for its Hausdorff distance to `geo2`.
`geo2`	`POINT`, `LINESTRING`, or `POLYGON`	A geospatial object to be measured for its Hausdorff distance to `geo1`.
`units`	`STRING`	Optional. Supported units are `'FEET'`, `'KILOMETERS'`, `'MILES'`, and `'METERS'`. The default value is `'METERS'`.
`use_spheroid`	`BOOLEAN`	Optional. If you set this argument to `TRUE`, this function uses a spheroid model instead of a spherical model. Defaults to `FALSE`.

Example

SQL

SELECT ST_HAUSDORFFDISTANCE(
        ST_POLYGON('POLYGON((1 1, 2 2, 1 2, 1 1))'),
        ST_POLYGON('POLYGON((0 0, 2 1, 2 0, 0 0))'),
        'METERS',
        TRUE);

Output: 156899.5136831999

ST_LENGTH

Returns the length of the specified line in the specified measurement unit. Returns 0 for all geography types except for LINESTRING. To return the total length of a POLYGON, use ST_PERIMETER. Syntax

SQL

ST_LENGTH(geo [, units] [, use_spheroid] )

Argument	Data Type	Description
`geo`	`LINESTRING`	A line that is to be measured for its length. The function accepts `POINT` and `POLYGON` data types, but returns `0`.
`units`	`STRING`	Optional. Supported units are `'FEET'`, `'KILOMETERS'`, `'MILES'`, and `'METERS'`. The default value is `'METERS'`.
`use_spheroid`	`BOOLEAN`	Optional. If you set this argument to `TRUE`, this function uses a spheroid model instead of a spherical model. Defaults to `FALSE`.

Example

SQL

SELECT ST_LENGTH(
        ST_LINESTRING('LINESTRING(1 2, 1 4)'),
        'METERS',
        false);

Output: 222390.10395618092

ST_LENGTH2D

Alias for ST_LENGTH.

ST_MINIMUMDISTANCETOSURFACE

Calculates the shortest distance between any point along a Euclidean line segment in three-dimensional space and the surface of the Earth. Two input points and their altitudes define this line segment. The line can go above or below the surface of the Earth. The function takes the difference of both points from the center of the Earth to calculate the distance between the nearest point of the line and the surface of the Earth. The function returns the distance in meters or another unit of measurement if specified. If the returned distance is positive, the shortest distance is above the surface. If the result is negative, the shortest distance is below the surface. Syntax

SQL

ST_MINIMUMDISTANCETOSURFACE(point1, altitude1, point2, altitude2 [, units] )

Argument	Data Type	Description
`point1`	`POINT`	A geospatial point that represents a Euclidean line with `point2`.
`altitude1`	`DOUBLE`	Distance from the surface of the Earth for `point1`. This argument uses meters, unless you specify a different unit of measurement with the `units` argument.
`point2`	`POINT`	A geospatial point that represents a Euclidean line with `point1`.
`altitude2`	`DOUBLE`	Distance from the surface of the Earth for `point2`. This argument uses meters, unless you specify a different unit of measurement with the `units` argument.
`units`	`VARCHAR`	Optional. This argument specifies the unit of measurement for the distance input arguments and the function output. Supported units are `'FEET'`, `'KILOMETERS'`, `'MILES'`, and `'METERS'`. The default value is `'METERS'`.

Examples This example takes a line from two points and calculates the distance of the nearest point to the surface of the Earth.

SQL

SELECT ST_MINIMUMDISTANCETOSURFACE(
    ST_POINT(0,0),1000.0,
	ST_POINT(0,1),1000.0,
	'METERS');

Output: 757.3734914669767 In this example, the output is negative, meaning the smallest distance is actually below the surface of the Earth.

SQL

SELECT ST_MINIMUMDISTANCETOSURFACE(
    ST_POINT(0,0),1000.0,
	ST_POINT(0,5),1000.0,
	'METERS');

Output: -5064.738915202208

ST_MAXDISTANCE

Returns the maximum distance between the specified arguments. ST_MAXDISTANCE returns the maximum distance in the specified unit of measurement. The use_spheroid optional argument enables the computation to use a spheroid model rather than a spherical one. Syntax

SQL

ST_MAXDISTANCE(geo1, geo2 [, units] [, use_spheroid] )

Argument	Data Type	Description
`geo1`	`POINT`, `LINESTRING`, or `POLYGON`	A geospatial object to be measured for its maximum distance to `geo2`.
`geo2`	`POINT`, `LINESTRING`, or `POLYGON`	A geospatial object to be measured for its maximum distance to `geo1`.
`units`	`STRING`	Optional. Supported units are `'FEET'`, `'KILOMETERS'`, `'MILES'`, and `'METERS'`. The default value is `'METERS'`.
`use_spheroid`	`BOOLEAN`	Optional. If you set this argument to `TRUE`, this function uses a spheroid model instead of a spherical model. Defaults to `FALSE`.

Example

SQL

SELECT ST_MAXDISTANCE(
        ST_POLYGON(ST_LINESTRING('LINESTRING(1 2, 1 4, 1 7, 1 2)')),
        ST_POLYGON(ST_LINESTRING('LINESTRING(1 2, 1 4, 1 5, 1 2)')),
        'METERS',
        false);

Output: 555975.2598904524

To use ST_MAXDISTANCE as a spatiotemporal function to calculate the maximum simultaneous distance between two linestring-timestamp array pairs, see the ST_MAXDISTANCE function in Spatiotemporal Measurement.

ST_PERIMETER

Returns the length of the exterior (outer ring) of the POLYGON in the specified unit of measurement. Returns 0 for all geography types except for POLYGON. To return the length of a LINESTRING, use ST_LENGTH. Syntax

SQL

ST_PERIMETER(geo, [, units] [, use_spheroid] )

Argument	Data Type	Description
`geo`	`POLYGON`	A `POLYGON` that is to be measured for its total perimeter length. The function accepts `POINT` and `LINESTRING` data types, but returns `0`.
`units`	`STRING`	Optional. Supported units are `'FEET'`, `'KILOMETERS'`, `'MILES'`, and `'METERS'`. The default value is `'METERS'`.
`use_spheroid`	`BOOLEAN`	Optional. If you set this argument to `TRUE`, this function uses a spheroid model instead of a spherical model. Defaults to `FALSE`.

Example

SQL

SELECT ST_PERIMETER(
        ST_POLYGON(ST_LINESTRING('LINESTRING(1 2, 1 3, 1 3, 1 2)')),
        'METERS',
        false);

Output: 222390.1039561809

ST_PERIMETER2D

Alias for ST_PERIMETER. Geospatial Data Types Spatial Operators Spatial Relationships

​ST_AREA

​ST_ANGLE

​ST_AZIMUTH

​ST_DISTANCE

​ST_DISTANCESPHERE

​ST_DISTANCESPHEROID

​ST_EUCLIDEANDISTANCE3D

​ST_HAUSDORFFDISTANCE

​ST_LENGTH

​ST_LENGTH2D

​ST_MINIMUMDISTANCETOSURFACE

​ST_MAXDISTANCE

​ST_PERIMETER

​ST_PERIMETER2D

​Related Links

ST_AREA

ST_ANGLE

ST_AZIMUTH

ST_DISTANCE

ST_DISTANCESPHERE

ST_DISTANCESPHEROID

ST_EUCLIDEANDISTANCE3D

ST_HAUSDORFFDISTANCE

ST_LENGTH

ST_LENGTH2D

ST_MINIMUMDISTANCETOSURFACE

ST_MAXDISTANCE

ST_PERIMETER

ST_PERIMETER2D

Related Links