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API · /epsg-api

Coordinate Systems API

healthy 3,984 Subscribers

Map projections and coordinate reference systems as an API — the EPSG dataset made queryable. Every CRS, from geographic systems like WGS 84 (the GPS standard, EPSG 4326) to projected ones like Web Mercator (3857), the UTM zones and national grids, has an EPSG code. Search the dataset by name to find the code you need, then resolve any code to its full definition: name, kind (geographic, projected, …), area of use, scope, and — most usefully — the ready-to-paste PROJ.4 string and WKT definition that GIS libraries (GDAL, PROJ, PostGIS, Leaflet, OpenLayers, QGIS, GeoPandas) consume directly. Search comes from the official EPSG Registry maintained by IOGP; the PROJ.4/WKT exports come from epsg.io. A geodesy / coordinate-reference-system resource — distinct from geocoding (addresses to coordinates), geohashing and administrative-boundary APIs. Ideal for GIS, mapping, surveying, remote-sensing and spatial-data applications.

#gis #coordinate-systems #epsg #projections #geodesy #mapping
api.oanor.com/epsg-api
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Machine-readable spec so AI agents can integrate this API.

/api/epsg-api/openapi.json
/api/epsg-api/llms.txt

Discovery: GET /api/index.json lists every API.

Coordinate Systems API — live data on the oanor API marketplace

API health

healthy
Uptime
100.00%
Server probes · 24h
Avg latency
464 ms
Server probes · 24h
Subscribers
3,984
active
Total calls
57
last 7 days
status Full status page → · 9 probes/24h

Pricing

Pick a tier — billed monthly, cancel anytime.

Free

Free

  • 2,380 calls / month
  • 2 requests / second
  • Hard cap (429 above quota, no overage)
  • 2,380 calls/month
  • 2 req/sec
  • Search + CRS + PROJ.4/WKT
  • No credit card
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Starter

€6.85 /month

  • 47,500 calls / month
  • 8 requests / second
  • Hard cap (429 above quota, no overage)
  • 47.5k calls/month
  • 8 req/sec
  • Area of use + scope
  • Email support
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Pro

€21.80 /month

  • 238,000 calls / month
  • 20 requests / second
  • Hard cap (429 above quota, no overage)
  • 238k calls/month
  • 20 req/sec
  • GIS & mapping apps
  • Priority support
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Mega

€58.10 /month

  • 850,000 calls / month
  • 50 requests / second
  • Hard cap (429 above quota, no overage)
  • 850k calls/month
  • 50 req/sec
  • Spatial-data platform
  • Dedicated SLA
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Related APIs

Other APIs with overlapping tags.

UTM Coordinate API — oanor API marketplace

UTM Coordinate API

UTM ↔ geographic coordinate conversion as an API, computed locally and deterministically on the WGS84 ellipsoid. The from-latlon endpoint projects a latitude and longitude into the Universal Transverse Mercator grid — returning the zone (1–60), the hemisphere, the latitude band letter, and the easting and northing in metres — using the Snyder/USGS Transverse Mercator series, which is accurate to a few millimetres within a zone; New York (40.7128, −74.0060) maps to zone 18N at about 583960 E, 4507351 N, and the canonical 45°N on a central meridian gives a northing of exactly 4982950.40 m. The to-latlon endpoint inverts it, recovering the latitude and longitude from a zone, hemisphere, easting and northing. Each zone is 6° of longitude wide with a 500000 m false easting on its central meridian and a 10000000 m false northing in the southern hemisphere. Latitude is valid from −80° to 84°. Everything is computed locally and deterministically, so it is instant and private. Ideal for GIS, surveying, mapping, geospatial, drone-mapping and location app developers, coordinate-conversion and grid-reference tools, and spatial software. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 2 endpoints. This is UTM on WGS84; for the polar regions use UPS and for an EPSG-code lookup use an EPSG API.

api.oanor.com/utm-api

 Geodesy API — oanor API marketplace

Geodesy API

Advanced geodesy beyond the simple great circle. The vincenty endpoint computes the distance between two latitude/longitude points on the WGS84 ellipsoid using Vincenty's inverse formula — accurate to within a millimetre, far better than the spherical approximation — plus the initial and final bearings, in metres, kilometres, miles and nautical miles. The rhumb endpoint computes the rhumb-line (loxodrome) distance and the single constant compass bearing that follows it — the path you steer by holding a heading, as used in marine and air navigation. The cross-track endpoint finds how far a point lies to the left or right of a great-circle path between two points (the cross-track distance) and how far along that path it is (the along-track distance). Everything is computed locally and deterministically, so it is instant and private. Ideal for marine and aviation navigation, surveying and GIS, route analysis, and precise mapping. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 4 endpoints. This is advanced geodesy; for simple great-circle distance, bearing, midpoint and destination use a geo-distance API and for coordinate-format conversion use a geo-convert API.

api.oanor.com/geodesy-api

 WKT API — oanor API marketplace

WKT API

Convert geometry between WKT (Well-Known Text) and GeoJSON, in both directions. WKT is the textual geometry format used by PostGIS, Spatialite, GEOS, JTS, Shapely and the OGC Simple Features standard (POINT (30 10), LINESTRING (...), POLYGON ((...))); GeoJSON is what web maps and JavaScript expect. The to-geojson endpoint turns a WKT string into a GeoJSON geometry, and to-wkt does the reverse from a GeoJSON geometry or Feature. Supports Point, LineString, Polygon, MultiPoint, MultiLineString, MultiPolygon and GeometryCollection. Perfect for bridging a spatial database and a front-end map, importing and exporting geometry, and data-migration scripts. Pure local computation — no key, no third-party service, instant; send large geometries via POST. Live, nothing stored. 3 endpoints. Distinct from coordinate-format conversion, EPSG/CRS lookups, slippy map tiles and GeoJSON geospatial metrics.

api.oanor.com/wkt-api

 GeoJSON API — oanor API marketplace

GeoJSON API

Measure GeoJSON geometry on the surface of the earth. Compute the true area of a Polygon or MultiPolygon (in square metres, square kilometres, hectares, acres and square miles), find the centroid of any GeoJSON, get the bounding box (west/south/east/north) and its centre, measure the length of a LineString or MultiLineString (in kilometres, metres, miles and nautical miles), and test whether a latitude/longitude point falls inside a polygon. Accepts geometries, Features and FeatureCollections; coordinates follow the GeoJSON [longitude, latitude] order. Perfect for mapping apps, geofencing, territory and catchment analysis, route distances and spatial dashboards. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 6 endpoints. Distinct from abstract shape geometry, coordinate-format conversion, slippy map tiles and administrative-boundary data.

api.oanor.com/geojson-api

Frequently asked questions

Quick answers about pricing, quotas, and integration.

How do I get an API key for Coordinate Systems API?
Sign up for free at oanor.com, generate an API key from the developer dashboard, and call Coordinate Systems API with the x-oanor-key header. No credit card needed for the free tier.
What's the rate limit for Coordinate Systems API?
Free tier allows 1 request per second. Paid plans scale up to 50 requests per second on the Mega tier. Hard limits return HTTP 429 above the quota — no surprise overage charges.
How much does Coordinate Systems API cost?
Coordinate Systems API has a free tier with 100 calls / month. Paid plans start at €6.85 / month with higher quotas and faster rate limits.
Can I cancel my subscription anytime?
Yes. Plans are billed monthly and you can cancel anytime from your billing dashboard. No long-term contracts and no cancellation fee.
Is Coordinate Systems API GDPR-compliant?
All requests to Coordinate Systems API go through our EU-based gateway. Your upstream API key never leaves our server and no personal data is shared with the upstream provider beyond the request you send.

Pick an endpoint from the list on the left to see its details and try it.

Code snippets

Sign up to get an API key, then call any path under your slug.

curl https://api.oanor.com/epsg-api/SOME_PATH \
  -H "x-oanor-key: oanor_test_..."
const res = await fetch("https://api.oanor.com/epsg-api/SOME_PATH", {
  headers: { "x-oanor-key": "oanor_test_..." }
});
const data = await res.json();
$ch = curl_init("https://api.oanor.com/epsg-api/SOME_PATH");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, ["x-oanor-key: oanor_test_..."]);
$response = curl_exec($ch);
import requests
r = requests.get(
    "https://api.oanor.com/epsg-api/SOME_PATH",
    headers={"x-oanor-key": "oanor_test_..."},
)
print(r.json())

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