ForHosting KIT · Developer Utilities

S2 cube face from lat/lon

Google's S2 geometry library tiles the Earth by projecting the unit sphere onto a cube, then recursively subdividing each face into a hierarchy of cells.

● BetaFree · in your browser

Run — free How it works & API

Use it from WebAPIEmailTelegramApp soon

Before you can encode an S2 cell id, compute a covering, or reason about region intersection, you need to know which of the six faces of that cube contains a given latitude and longitude. This capability accepts WGS84 lat and lon, converts them to a unit direction vector, and returns the S2 face index (0 through 5), a readable face name such as +X or -Z, the Cartesian unit components, and the UV coordinates of the point on that face in the conventional minus-one to plus-one range. The algorithm is pure analytic math with no network calls and no random state, so the free browser path and the paid API path always agree. Use it when you are building spatial indexes, teaching spherical geometry, or validating that your own S2 bindings pick the same face as the reference library for edge cases near face boundaries.

How to use it

Enter your values in the form above. The tool checks them before calculating and shows the result on the same page.

Check your inputs

Use the labels and units shown next to each field. If something is missing or outside the allowed range, the page points to the field to fix.

Use it again or automate it

Use the browser tool for individual checks and the API when you need the same capability in an automated workflow.

What you can do with it

Get an answer now

Enter one set of values and see the result without building a spreadsheet or script.

Compare scenarios

Change one value at a time and rerun the calculation to understand what affects the result.

Automate repeated work

Use the API when the same calculation needs to run inside your product or workflow.

FAQ

How do I use this capability?

Complete the fields above and run it on this page. The form highlights anything that needs attention.

For developers — API access

Everything on this page is available programmatically. This section is for teams who want to wire it into their own systems; everyone else can just use the tool above.

API endpoint

POSThttps://api.kit.forhosting.com/geo/s2-face-from-latlon

Prefer to automate it? One authenticated POST creates the task; the result comes back by webhook or a signed link. The same capability also runs here on the web, by email and from Telegram — and soon from our app too.

Call it from your stack

curl -X POST https://api.kit.forhosting.com/geo/s2-face-from-latlon \
  -H "Authorization: Bearer $KIT_KEY" \
  -H "Content-Type: application/json" \
  -d '{"lat":37.7749,"lon":-122.4194}'

const res = await fetch("https://api.kit.forhosting.com/geo/s2-face-from-latlon", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${process.env.KIT_KEY}`,
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    "lat": 37.7749,
    "lon": -122.4194
  })
});
const { task_id } = await res.json();

import os, requests

res = requests.post(
    "https://api.kit.forhosting.com/geo/s2-face-from-latlon",
    headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
    json={
    "lat": 37.7749,
    "lon": -122.4194
},
)
task_id = res.json()["task_id"]

<?php
$res = file_get_contents("https://api.kit.forhosting.com/geo/s2-face-from-latlon", false, stream_context_create([
  "http" => [
    "method"  => "POST",
    "header"  => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
    "content" => '{"lat":37.7749,"lon":-122.4194}',
  ],
]));
$task = json_decode($res, true);

body := bytes.NewBufferString(`{"lat":37.7749,"lon":-122.4194}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/geo/s2-face-from-latlon", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)

Example request

{
  "lat": 37.7749,
  "lon": -122.4194
}

Example response

{
  "task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
  "type": "geo.s2_face_from_latlon",
  "status": "queued",
  "_links": {
    "result": "/tasks/tsk_…/result"
  }
}

The API is asynchronous: the call returns a task_id immediately and the result arrives by webhook. Polling is capped at 1 req/s per task.

Pricing

Per request$0.002

Published price — no tokens, no invented credits. A failed task is never charged.

Errors

HTTP	Code	Meaning
`401`	`unauthorized`	Missing or invalid API key.
`402`	`insufficient_balance`	Your balance doesn't cover the task price.
`404`	`unknown_type`	That task type doesn't exist.
`429`	`rate_limited`	Too many requests. Use the webhook instead of polling.

Read the full KIT documentation →