Functions for Working with Geometry

Geometry

Geometry functions allow you to calculate perimeter and area for geometric types such as POLYGON, LINESTRING, MULTIPOLYGON, MULTILINESTRING, RING, and POINT. Use geometries in Geometry type. If the input value is NULL, all functions below will return 0.

perimeterCartesian

Calculates the perimeter of the given Geometry object in the Cartesian (flat) coordinate system.

Syntax

perimeterCartesian(geom)

Arguments

• geom — Geometry object. Geometry.

Returned values

• Number — Perimeter of the object in the coordinate system units. Float64.

Example

CREATE TABLE IF NOT EXISTS geo_dst (geom Geometry) ENGINE = Memory();
INSERT INTO geo_dst SELECT readWKT('POLYGON((0 0,1 0,1 1,0 1,0 0))');
SELECT perimeterCartesian(geom) FROM geo_dst;

┌─perimeterCartesian(geom)─┐
│ 4.0                      │
└──────────────────────────┘

areaCartesian

Calculates the area of the given Geometry object in the Cartesian coordinate system.

Syntax

areaCartesian(geom)

Arguments

• geom — Geometry object. Geometry.

Returned values

• Number — Area of the object in coordinate system units. Float64.

Example

CREATE TABLE IF NOT EXISTS geo_dst (geom Geometry) ENGINE = Memory();
INSERT INTO geo_dst SELECT readWKT('POLYGON((0 0,1 0,1 1,0 1,0 0))');
SELECT areaCartesian(geom) FROM geo_dst;

┌─areaCartesian(geom)─┐
│ -1                  │
└─────────────────────┘

perimeterSpherical

Calculates the perimeter of a Geometry object on the surface of a sphere.

Syntax

perimeterSpherical(geom)

Arguments

• geom — Geometry object. Geometry.

Returned values

• Number — Perimeter. Float64.

Example

CREATE TABLE IF NOT EXISTS geo_dst (geom Geometry) ENGINE = Memory();
INSERT INTO geo_dst SELECT readWKT('LINESTRING(0 0,1 0,1 1,0 1,0 0)');
SELECT perimeterSpherical(geom) FROM geo_dst;

┌─perimeterSpherical(geom)─┐
│ 0                        │
└──────────────────────────┘

areaSpherical

Calculates the area of a Geometry object on the surface of a sphere.

Syntax

areaSpherical(geom)

Arguments

• geom — Geometry. Geometry.

Returned values

• Number — Area. Float64.

Example

CREATE TABLE IF NOT EXISTS geo_dst (geom Geometry) ENGINE = Memory();
INSERT INTO geo_dst SELECT readWKT('POLYGON((0 0,1 0,1 1,0 1,0 0))');
SELECT areaSpherical(geom) FROM geo_dst;

┌─areaSpherical(geom)────┐
│ -0.0003046096848622019 │
└────────────────────────┘