POST /geometry/data

Validates a GeoJSON geometry and returns calculated site data: area, centroid, and a BNG WKT string suitable for placing orders.

Base URL: https://geoapi.geocerta.io

Sandbox URL: https://geoapi-staging.geocerta.io

Authentication required. Include your API key in the api-key header. See Authentication.

Endpoint

POST /geometry/data

Content-Type: application/json

Request Body

The request body is a GeoJSON geometry object in WGS84 (EPSG:4326).

Field	Type	Required	Description
type	string	Yes	GeoJSON geometry type. One of Point, Polygon, MultiPolygon.
coordinates	array	Yes	GeoJSON coordinates in WGS84 (longitude, latitude order).

Response

200 OK — returns a result object. Check is_valid before using the other fields.

Invalid geometry

Returned when the geometry cannot be parsed, is not a closed polygon, or contains self-intersections.

Valid geometry

Response Fields

Field	Type	Description
is_valid	boolean	Whether the geometry is valid.
area_sq_meters	number	Site area in square metres. 0 for points.
x	number	Centroid Easting (British National Grid).
y	number	Centroid Northing (British National Grid).
centroid	GeoJSON Point	Centroid in WGS84 ([longitude, latitude]).
wkt	string	Site geometry as a WKT string in British National Grid (BNG). Pass this to POST /orders.
geometry	GeoJSON geometry	The input geometry (WGS84).

Errors

Status	Message	Cause
400	Bad Request	type is missing or not a supported geometry type, or coordinates is missing
401	Unauthorized	Missing or invalid API key

Example

curl -X POST https://geoapi.geocerta.io/geometry/data \
  -H "Content-Type: application/json" \
  -H "api-key: YOUR_API_KEY" \
  -d '{
    "type": "Polygon",
    "coordinates": [
      [
        [-0.1280, 51.5030],
        [-0.1270, 51.5030],
        [-0.1270, 51.5036],
        [-0.1280, 51.5036],
        [-0.1280, 51.5030]
      ]
    ]
  }'