Geodesic Inverse

{
  "asOf": "2026-10-11T08:41:06.238Z",
  "converged": true,
  "degraded": false,
  "disclaimer": "Screening signal computed from the named public source. Not financial, legal or investment advice; provided as is. Verify at the source before acting.",
  "ellipsoid": "WGS84",
  "ellipsoidalDistanceM": 3983079.7485,
  "finalBearingDeg": 245.908169,
  "haversineDistanceM": 3974341.69,
  "haversineInitialBearingDeg": 273.841961,
  "haversineMinusEllipsoidalM": -8738.059,
  "initialBearingDeg": 273.887299,
  "initialCompass": "W",
  "iterations": 5,
  "kilometers": 3983.079748,
  "miles": 2474.971012,
  "nauticalMiles": 2150.691009,
  "notChecked": [
    "terrain, roads, flight paths or sea lanes (this is the shortest line on the ellipsoid surface)",
    "elevation above the ellipsoid",
    "…1 more"
  ],
  "reasons": [
    "Haversine on a sphere differs by -8738.1 m (-0.219 percent).",
    "Vincenty converged in 5 iteration(s)."
  ],
  "source": "Vincenty (1975) inverse formula on WGS84, computed locally",
  "summary": "3983.08 km (2474.971 mi, 2150.691 nmi) on the WGS84 ellipsoid, initial bearing 273.887 degrees W.",
  "verdict": "COMPUTED"
}

# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i 'https://geo-calc.x402tookit.com/geodesic-inverse?lat1=40.6413&lat2=33.9416&lon1=-73.7781&lon2=-118.4085'

# x402 v2 sends the challenge base64-encoded in the PAYMENT-REQUIRED header (v1 sends it in the body).
# To read the header:
curl -sS -g -o /dev/null -D - 'https://geo-calc.x402tookit.com/geodesic-inverse?lat1=40.6413&lat2=33.9416&lon1=-73.7781&lon2=-118.4085' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 --decode

// npm i @x402/fetch @x402/evm viem
import { wrapFetchWithPayment, x402Client } from "@x402/fetch";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

// Pays at most $0.02 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.02" });
registerExactEvmScheme(client, { signer: privateKeyToAccount(process.env.EVM_PRIVATE_KEY) });
const pay = wrapFetchWithPayment(fetch, client);

// Not sure it's safe to pay? ToolVet checks it first for $0.005. Pay for that from a separate
// client: this one is capped at $0.02 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fgeo-calc.x402tookit.com%2Fgeodesic-inverse
const res = await pay("https://geo-calc.x402tookit.com/geodesic-inverse?lat1=40.6413&lat2=33.9416&lon1=-73.7781&lon2=-118.4085");
console.log(res.status, await res.text());

# pip install "x402[requests,evm]"
import os
from eth_account import Account
from x402 import x402ClientSync
from x402.http.clients import x402_requests
from x402.mechanisms.evm import EthAccountSigner
from x402.mechanisms.evm.exact.register import register_exact_evm_client

# Pays at most $0.02 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.02"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.get("https://geo-calc.x402tookit.com/geodesic-inverse?lat1=40.6413&lat2=33.9416&lon1=-73.7781&lon2=-118.4085")
    print(res.status_code, res.text)