Area-weighted polygon centroid API

Computes the true area-weighted centroid (center of mass) of a polygon via the shoelace centroid formula with a cosine-latitude correction — not the naive vertex average. Answers 'Where is the geometric center of this polygon?', 'What is the centroid of a geofence for label placement?'.

Price$0.06per request

MethodPOST

Route/v1/geo/polygon-centroid

StatusLive

MIME typeapplication/json

Rate limit120/minute

Cache0s public

geogispolygoncentroidcenter-of-massshoelacegeofencelabel-pointgeometry

API URLhttps://x402.hexl.dev/v1/geo/polygon-centroid

Integration docs

Example request

{
  "polygon": [
    {
      "latitude": 0,
      "longitude": 0
    },
    {
      "latitude": 0,
      "longitude": 4
    },
    {
      "latitude": 3,
      "longitude": 4
    },
    {
      "latitude": 3,
      "longitude": 0
    }
  ]
}

Example response

{
  "vertices": 4,
  "centroid": {
    "latitude": 1.5,
    "longitude": 2
  },
  "method": "area-weighted",
  "interpretation": "Area-weighted centroid: 1.5, 2 (the polygon's center of mass, not the vertex average)."
}

Input schema

{
  "type": "object",
  "required": [
    "polygon"
  ],
  "properties": {
    "polygon": {
      "type": "array",
      "items": {
        "type": "object",
        "properties": {
          "latitude": {
            "type": "number"
          },
          "longitude": {
            "type": "number"
          }
        }
      },
      "examples": [
        [
          {
            "latitude": 0,
            "longitude": 0
          },
          {
            "latitude": 0,
            "longitude": 4
          },
          {
            "latitude": 3,
            "longitude": 4
          },
          {
            "latitude": 3,
            "longitude": 0
          }
        ]
      ]
    }
  }
}

Output schema

{
  "type": "object",
  "additionalProperties": true
}