geo_polygon_area()

Calculates the area of a polygon or a multipolygon on Earth.

Syntax

geo_polygon_area(polygon)

Parameters

Returns

The area of a polygon or a multipolygon, in square meters, on Earth. If the polygon or the multipolygon is invalid, the query will produce a null result.

Polygon definition and constraints

dynamic({“type”: “Polygon”,“coordinates”: [ LinearRingShell, LinearRingHole_1, …, LinearRingHole_N ]})

dynamic({“type”: “MultiPolygon”,“coordinates”: [[ LinearRingShell, LinearRingHole_1, …, LinearRingHole_N ], …, [LinearRingShell, LinearRingHole_1, …, LinearRingHole_M]]})

• LinearRingShell is required and defined as a counterclockwise ordered array of coordinates [[lng_1,lat_1],…,[lng_i,lat_i],…,[lng_j,lat_j],…,[lng_1,lat_1]]. There can be only one shell.
• LinearRingHole is optional and defined as a clockwise ordered array of coordinates [[lng_1,lat_1],…,[lng_i,lat_i],…,[lng_j,lat_j],…,[lng_1,lat_1]]. There can be any number of interior rings and holes.
• LinearRing vertices must be distinct with at least three coordinates. The first coordinate must be equal to the last. At least four entries are required.
• Coordinates [longitude, latitude] must be valid. Longitude must be a real number in the range [-180, +180] and latitude must be a real number in the range [-90, +90].
• LinearRingShell encloses at most half of the sphere. LinearRing divides the sphere into two regions. The smaller of the two regions will be chosen.
• LinearRing edge length must be less than 180 degrees. The shortest edge between the two vertices will be chosen.
• LinearRings must not cross and must not share edges. LinearRings may share vertices.

Examples

The following example calculates NYC Central Park area.

let central_park = dynamic({"type":"Polygon","coordinates":[[[-73.9495,40.7969],[-73.95807266235352,40.80068603561921],[-73.98201942443848,40.76825672305777],[-73.97317886352539,40.76455136505513],[-73.9495,40.7969]]]});
print area = geo_polygon_area(central_park)

Output

The following example performs union of polygons in multipolygon and calculates area on the unified polygon.

let polygons = dynamic({"type":"MultiPolygon","coordinates":[[[[-73.9495,40.7969],[-73.95807266235352,40.80068603561921],[-73.98201942443848,40.76825672305777],[-73.97317886352539,40.76455136505513],[-73.9495,40.7969]]],[[[-73.94262313842773,40.775991804565585],[-73.98107528686523,40.791849155467695],[-73.99600982666016,40.77092185281977],[-73.96150588989258,40.75609977566361],[-73.94262313842773,40.775991804565585]]]]});
print polygons_union_area = geo_polygon_area(polygons)

Output

The following example calculates top 5 biggest US states by area.

US_States
| project name = features.properties.NAME, polygon = geo_polygon_densify(features.geometry)
| project name, area = geo_polygon_area(polygon)
| top 5 by area desc

Output

The following example returns True because of the invalid polygon.

print isnull(geo_polygon_area(dynamic({"type": "Polygon","coordinates": [[[0,0],[10,10],[10,10],[0,0]]]})))

Output