geoprimitives
Find the area centroid of a polygon: a representative point for labelling, joining, or reverse geocoding a shape you only have a boundary for. It is the centre of mass of the area with holes subtracted, not the average of the vertices, so densely sampled edges do not drag it. Know what a centroid is not: on a concave or ring-shaped polygon the centre of mass can fall outside the polygon itself, and this endpoint returns it anyway rather than nudging the point inside. Test it with POST /v1/pip if you need a point that is guaranteed to be inside. Not turf's centroid, which is the arithmetic mean of the vertices and drifts towards whichever part of the boundary happens to be densely sampled. The moment integral is evaluated in a Lambert cylindrical equal-area projection of the WGS 84 authalic sphere, so the cos(latitude) area weighting is right at high latitude, then inverted back to longitude and latitude. Non-areal input, and polygons that enclose zero area, fall back to the vertex mean and say so in the method field. Input is EPSG:4326 only. Limits: 100000 positions across the whole document, 1 MiB request body.
The wallet the 402 directs payment to. Its whole payment record — every payer, every chain — is on the merchant page.
Asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913
The payTo wallet does not resolve to a registered ERC-8004 agent. That is not a verdict on the service — most of the catalog is unregistered.
Accepts
The payment requirements as published to the catalog. Read the live 402 before paying — a price here is a claim, not a quote.
Pay 0.01 USDC on Base to 0x76A5…68FCe. The signed payment is good for 5 minutes.
- Paid to
- 0x76A5…68FCe
- USD Coin contract
- 0x8335…02913
- Payment window
- 5 minutes
- As published
- 10000 smallest units
The catalog’s raw entry
[
{
"asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
"extra": {
"name": "USD Coin",
"version": "2"
},
"payTo": "0x76A51b5Dd3729950B3b60c17f19252d221968FCe",
"amount": "10000",
"scheme": "exact",
"network": "eip155:8453",
"maxTimeoutSeconds": 300
}
]Extensions
{
"bazaar": {
"info": {
"input": {
"body": {
"geojson": {
"type": "Polygon",
"coordinates": [
[
[
-150,
61
],
[
-149.9,
61
],
[
-149.9,
61.05
],
[
-150,
61.05
],
[
-150,
61
]
]
]
}
},
"type": "http",
"method": "POST",
"bodyType": "json"
},
"output": {
"type": "json",
"example": {
"op": "centroid",
"notes": [],
"method": "area_centroid",
"geojson": {
"type": "Feature",
"geometry": {
"type": "Point",
"coordinates": [
-149.95000000000005,
61.02499021252749
]
},
"properties": null
},
"accuracy": "True area centroid, computed in an equal-area space so the cos(latitude) weighting is right, with holes subtracted. Not the arithmetic mean of the vertices.",
"inputVertices": 5
}
}
},
"schema": {
"type": "object",
"$schema": "https://json-schema.org/draft/2020-12/schema",
"required": [
"input"
],
"properties": {
"input": {
"type": "object",
"required": [
"type",
"method",
"bodyType",
"body"
],
"properties": {
"body": {
"type": "object",
"required": [
"geojson"
],
"properties": {
"geojson": {
"type": "object",
"description": "A GeoJSON Feature, FeatureCollection or Geometry in EPSG:4326, longitude then latitude in degrees. At most 100000 positions across the whole document."
}
},
"additionalProperties": false
},
"type": {
"type": "string",
"const": "http"
},
"method": {
"enum": [
"POST"
],
"type": "string"
},
"bodyType": {
"enum": [
"json",
"form-data",
"text"
],
"type": "string"
}
},
"additionalProperties": false
},
"output": {
"type": "object",
"required": [
"type"
],
"properties": {
"type": {
"type": "string"
},
"example": {
"type": "object"
}
}
}
}
}
}
}Provenance
- Seen in the source catalog
- 2026-08-21 17:25Z
- Last indexed by Roundhouse
- 2026-09-20 17:20Z
- Last enriched (probe, favicon, geo)
- 2026-09-23 21:45Z
- x402 version
- 2
- Max timeout
- 300s
- Liveness probe
- HTTP 404
Hand this page to an agent
Copy the prompt and paste it into Claude, an MCP client or your own agent — it will vet this service and call it over the free read API. No key, no account.
GET api.roundhouseai.io/v0/endpoints
This endpoint's own trailing-30-day call count, as published by the upstream catalog and snapshotted daily. 27 snapshots so far. Verified volume counts only settlements with an on-chain EIP-3009 marker.
Show the promptHide the prompt
Using Roundhouse, look up the x402 service geoprimitives and tell me whether it is worth paying: what a call costs, whether the endpoint answered when last probed, and what its payment record actually shows. curl -s 'https://api.roundhouseai.io/v0/endpoints?q=geoprimitives' curl -s 'https://api.roundhouseai.io/v0/merchants/<the payTo wallet returned above>' Then call it: read the price from the live 402 at https://api.geoprimitives.dev/v1/geometry/centroid, never from a cached figure, and pay with an x402 client. The /v0 API needs an API key (`authorization: Bearer rh_live_…`) on everything except /v0/unified* and /v0/endpoints. Mint a personal key for $0.01 at GET https://api.roundhouseai.io/v0/test/x402, or use an organization key from https://roundhouseai.io/dashboard/team. If you do not have Roundhouse tools or skills installed, read https://roundhouseai.io/skill.md first — it is the whole procedure.