Great-Circle Geodesy API

Q: Can bounding boxes cross the international date line?

Yes. crossesAntimeridian is true and west is greater than east; boxes reaching a pole instead set spansAllLongitudes and use -180 to 180.

REAL DATA

Great-circle distance, bearings, destinations and bounding boxes for WGS 84 coordinates on an explicitly documented mean-Earth sphere.

Authoritative reference data or standards computation

Base URL: /api/geodesy
Category: Geo & Reference
Capabilities: 3 routes
Last updated: July 30, 2026

Data source: ITU-R P.1511-3 average WGS 84 Earth radius, with coordinate semantics from RFC 5870

GET /api/geodesy/distance Calculate spherical great-circle distance and bearings between two points Computed answer

Live requestRuns against the public API

No key required

GET/api/geodesy/distance?lat1=51.5074&lon1=-0.1278&lat2=40.7128&lon2=-74.0060

Request parameters

lat1required

Latitude in WGS 84 decimal degrees, from -90 to 90 inclusive.

lon1required

Longitude in WGS 84 decimal degrees, from -180 to 180 inclusive; +180 canonicalizes to -180.

lat2required

Latitude in WGS 84 decimal degrees, from -90 to 90 inclusive.

lon2required

Longitude in WGS 84 decimal degrees, from -180 to 180 inclusive; +180 canonicalizes to -180.

Advanced response options4 options

fields

Return only these fields (comma-separated). Mutually exclusive with 'exclude'.

exclude

Return all fields except these (comma-separated).

prettydefault false

Pretty-print the JSON response.

unwrapdefault false

Drop the envelope: return the raw array/object without data/meta wrapper.

Response

Example parameters are ready. Send the request to inspect the live response.

Route reference

Code, request parameters, response fields and verified examples 8 params · 11 fields · 3 examples

Code samples Ready-to-copy requests in 4 languages

curl JavaScript Python PHP

curl "https://randomapi.dev/api/geodesy/distance?lat1=51.5074&lon1=-0.1278&lat2=40.7128&lon2=-74.0060"

const res = await fetch("https://randomapi.dev/api/geodesy/distance?lat1=51.5074&lon1=-0.1278&lat2=40.7128&lon2=-74.0060");
const { data, meta } = await res.json();

import requests

data = requests.get("https://randomapi.dev/api/geodesy/distance?lat1=51.5074&lon1=-0.1278&lat2=40.7128&lon2=-74.0060").json()["data"]

$json = json_decode(file_get_contents(
  "https://randomapi.dev/api/geodesy/distance?lat1=51.5074&lon1=-0.1278&lat2=40.7128&lon2=-74.0060"
), true);
$data = $json["data"];

Parameters Route-specific request inputs 4

Parameter	Type	Default & allowed	Description
`lat1` required	float	allowed: -90 – 90 example: 51.5074	Latitude in WGS 84 decimal degrees, from -90 to 90 inclusive.
`lon1` required	float	allowed: -180 – 180 example: -0.1278	Longitude in WGS 84 decimal degrees, from -180 to 180 inclusive; +180 canonicalizes to -180.
`lat2` required	float	allowed: -90 – 90 example: 40.7128	Latitude in WGS 84 decimal degrees, from -90 to 90 inclusive.
`lon2` required	float	allowed: -180 – 180 example: -74.006	Longitude in WGS 84 decimal degrees, from -180 to 180 inclusive; +180 canonicalizes to -180.

lat1 float required

Latitude in WGS 84 decimal degrees, from -90 to 90 inclusive.

allowed: -90 – 90

example: lat1=51.5074

lon1 float required

Longitude in WGS 84 decimal degrees, from -180 to 180 inclusive; +180 canonicalizes to -180.

allowed: -180 – 180

example: lon1=-0.1278

lat2 float required

Latitude in WGS 84 decimal degrees, from -90 to 90 inclusive.

allowed: -90 – 90

example: lat2=40.7128

lon2 float required

Longitude in WGS 84 decimal degrees, from -180 to 180 inclusive; +180 canonicalizes to -180.

allowed: -180 – 180

example: lon2=-74.006

Universal parameters Shared response and formatting options 4

Parameter	Type	Default & allowed	Description
`fields`	list	example: from,to	Return only these fields (comma-separated). Mutually exclusive with 'exclude'.
`exclude`	list	example: radiusMeters	Return all fields except these (comma-separated).
`pretty`	boolean	default: false example: true	Pretty-print the JSON response.
`unwrap`	boolean	default: false example: true	Drop the envelope: return the raw array/object without data/meta wrapper.

fields list

Return only these fields (comma-separated). Mutually exclusive with 'exclude'.

example: fields=from,to

exclude list

Return all fields except these (comma-separated).

example: exclude=radiusMeters

pretty boolean

Pretty-print the JSON response.

default: false

example: pretty=true

unwrap boolean

Drop the envelope: return the raw array/object without data/meta wrapper.

default: false

example: unwrap=true

Response schema Fields returned in each record 11

Field	Type	Description	Example
`from`	object	Canonical first coordinate as latitude/longitude.	{"latitude":51.5074,"longitude":-0.1278}
`to`	object	Canonical second coordinate as latitude/longitude.	{"latitude":40.7128,"longitude":-74.006}
`centralAngleDegrees`	float	Great-circle central angle in degrees.	50.094212
`distanceMeters`	float	Great-circle arc length on the exposed spherical model, in meters.	5570229.874
`distanceKilometers`	float	The same arc length in kilometers.	5570.229874
`initialBearingDegrees` nullable	float	Forward bearing at the first point, clockwise from true north; null for non-unique geometry or a polar first point.	288.33
`finalBearingDegrees` nullable	float	Forward bearing on arrival, clockwise from true north; null for non-unique geometry or a polar destination.	231.21
`isCoincident`	boolean	True when both inputs identify the same point on the sphere.	false
`isAntipodal`	boolean	True for diametrically opposite points, where infinitely many great circles connect them.	false
`model`	string	Explicit calculation model: mean-earth-sphere (not an ellipsoidal or road distance).	mean-earth-sphere
`radiusMeters`	float	IUGG mean Earth radius used by every calculation, in meters.	6371008.8

from object

Canonical first coordinate as latitude/longitude.

example: {"latitude":51.5074,"longitude":-0.1278}

to object

Canonical second coordinate as latitude/longitude.

example: {"latitude":40.7128,"longitude":-74.006}

centralAngleDegrees float

Great-circle central angle in degrees.

example: 50.094212

distanceMeters float

Great-circle arc length on the exposed spherical model, in meters.

example: 5570229.874

distanceKilometers float

The same arc length in kilometers.

example: 5570.229874

initialBearingDegrees float nullable

Forward bearing at the first point, clockwise from true north; null for non-unique geometry or a polar first point.

example: 288.33

finalBearingDegrees float nullable

Forward bearing on arrival, clockwise from true north; null for non-unique geometry or a polar destination.

example: 231.21

isCoincident boolean

True when both inputs identify the same point on the sphere.

example: false

isAntipodal boolean

True for diametrically opposite points, where infinitely many great circles connect them.

example: false

model string

Explicit calculation model: mean-earth-sphere (not an ellipsoidal or road distance).

example: mean-earth-sphere

radiusMeters float

IUGG mean Earth radius used by every calculation, in meters.

example: 6371008.8

Documented examples

Build-generated requests and complete responses 3

London to New York /api/geodesy/distance?lat1=51.5074&lon1=-0.1278&lat2=40.7128&lon2=-74.0060

GET /api/geodesy/distance?lat1=51.5074&lon1=-0.1278&lat2=40.7128&lon2=-74.0060

{
  "data": {
    "from": {
      "latitude": 51.5074,
      "longitude": -0.1278
    },
    "to": {
      "latitude": 40.7128,
      "longitude": -74.006
    },
    "centralAngleDegrees": 50.09421156,
    "distanceMeters": 5570229.874,
    "distanceKilometers": 5570.229874,
    "initialBearingDegrees": 288.329701594,
    "finalBearingDegrees": 231.212616824,
    "isCoincident": false,
    "isAntipodal": false,
    "model": "mean-earth-sphere",
    "radiusMeters": 6371008.8
  },
  "meta": {
    "endpoint": "geodesy",
    "route": "/distance",
    "params": {
      "lat1": 51.5074,
      "lon1": -0.1278,
      "lat2": 40.7128,
      "lon2": -74.006
    },
    "generatedAt": "2026-07-30T15:14:08.000Z"
  }
}

Copenhagen to Tokyo /api/geodesy/distance?lat1=55.6761&lon1=12.5683&lat2=35.6762&lon2=139.6503

GET /api/geodesy/distance?lat1=55.6761&lon1=12.5683&lat2=35.6762&lon2=139.6503

{
  "data": {
    "from": {
      "latitude": 55.6761,
      "longitude": 12.5683
    },
    "to": {
      "latitude": 35.6762,
      "longitude": 139.6503
    },
    "centralAngleDegrees": 78.143341114,
    "distanceMeters": 8689155.085,
    "distanceKilometers": 8689.155085,
    "initialBearingDegrees": 41.466326635,
    "finalBearingDegrees": 152.635624504,
    "isCoincident": false,
    "isAntipodal": false,
    "model": "mean-earth-sphere",
    "radiusMeters": 6371008.8
  },
  "meta": {
    "endpoint": "geodesy",
    "route": "/distance",
    "params": {
      "lat1": 55.6761,
      "lon1": 12.5683,
      "lat2": 35.6762,
      "lon2": 139.6503
    },
    "generatedAt": "2026-07-30T15:14:08.000Z"
  }
}

Antipodal edge case /api/geodesy/distance?lat1=0&lon1=0&lat2=0&lon2=180

GET /api/geodesy/distance?lat1=0&lon1=0&lat2=0&lon2=180

{
  "data": {
    "from": {
      "latitude": 0,
      "longitude": 0
    },
    "to": {
      "latitude": 0,
      "longitude": -180
    },
    "centralAngleDegrees": 180,
    "distanceMeters": 20015114.442,
    "distanceKilometers": 20015.114442,
    "initialBearingDegrees": null,
    "finalBearingDegrees": null,
    "isCoincident": false,
    "isAntipodal": true,
    "model": "mean-earth-sphere",
    "radiusMeters": 6371008.8
  },
  "meta": {
    "endpoint": "geodesy",
    "route": "/distance",
    "params": {
      "lat1": 0,
      "lon1": 0,
      "lat2": 0,
      "lon2": -180
    },
    "generatedAt": "2026-07-30T15:14:08.000Z"
  }
}

GET /api/geodesy/destination Find the great-circle destination from a point, bearing and distance Computed answer

Uses the exposed sphere and normalizes longitude. Non-zero journeys from an exact pole are rejected because initial compass bearing is undefined there.

Live requestRuns against the public API

No key required

GET/api/geodesy/destination?lat=55.6761&lon=12.5683&bearing=90&distanceKm=1000

Request parameters

latrequired

Latitude in WGS 84 decimal degrees, from -90 to 90 inclusive.

lonrequired

Longitude in WGS 84 decimal degrees, from -180 to 180 inclusive; +180 canonicalizes to -180.

bearingrequired

Initial bearing clockwise from true north, 0–360 degrees; 360 canonicalizes to 0.

distanceKmrequired

Non-negative great-circle arc distance in kilometers, capped at 40031 (about one mean-Earth circumference).

Advanced response options4 options

fields

Return only these fields (comma-separated). Mutually exclusive with 'exclude'.

exclude

Return all fields except these (comma-separated).

prettydefault false

Pretty-print the JSON response.

unwrapdefault false

Drop the envelope: return the raw array/object without data/meta wrapper.

Response

Example parameters are ready. Send the request to inspect the live response.

Route reference

Code, request parameters, response fields and verified examples 8 params · 7 fields · 3 examples

Code samples Ready-to-copy requests in 4 languages

curl JavaScript Python PHP

curl "https://randomapi.dev/api/geodesy/destination?lat=55.6761&lon=12.5683&bearing=90&distanceKm=1000"

const res = await fetch("https://randomapi.dev/api/geodesy/destination?lat=55.6761&lon=12.5683&bearing=90&distanceKm=1000");
const { data, meta } = await res.json();

import requests

data = requests.get("https://randomapi.dev/api/geodesy/destination?lat=55.6761&lon=12.5683&bearing=90&distanceKm=1000").json()["data"]

$json = json_decode(file_get_contents(
  "https://randomapi.dev/api/geodesy/destination?lat=55.6761&lon=12.5683&bearing=90&distanceKm=1000"
), true);
$data = $json["data"];

Parameters Route-specific request inputs 4

Parameter	Type	Default & allowed	Description
`lat` required	float	allowed: -90 – 90 example: 55.6761	Latitude in WGS 84 decimal degrees, from -90 to 90 inclusive.
`lon` required	float	allowed: -180 – 180 example: 12.5683	Longitude in WGS 84 decimal degrees, from -180 to 180 inclusive; +180 canonicalizes to -180.
`bearing` required	float	allowed: 0 – 360 example: 90	Initial bearing clockwise from true north, 0–360 degrees; 360 canonicalizes to 0.
`distanceKm` required	float	allowed: 0 – 40031 example: 1000	Non-negative great-circle arc distance in kilometers, capped at 40031 (about one mean-Earth circumference).

lat float required

Latitude in WGS 84 decimal degrees, from -90 to 90 inclusive.

allowed: -90 – 90

example: lat=55.6761

lon float required

Longitude in WGS 84 decimal degrees, from -180 to 180 inclusive; +180 canonicalizes to -180.

allowed: -180 – 180

example: lon=12.5683

bearing float required

Initial bearing clockwise from true north, 0–360 degrees; 360 canonicalizes to 0.

allowed: 0 – 360

example: bearing=90

distanceKm float required

Non-negative great-circle arc distance in kilometers, capped at 40031 (about one mean-Earth circumference).

allowed: 0 – 40031

example: distanceKm=1000

Universal parameters Shared response and formatting options 4

Parameter	Type	Default & allowed	Description
`fields`	list	example: origin,bearingDegrees	Return only these fields (comma-separated). Mutually exclusive with 'exclude'.
`exclude`	list	example: radiusMeters	Return all fields except these (comma-separated).
`pretty`	boolean	default: false example: true	Pretty-print the JSON response.
`unwrap`	boolean	default: false example: true	Drop the envelope: return the raw array/object without data/meta wrapper.

fields list

Return only these fields (comma-separated). Mutually exclusive with 'exclude'.

example: fields=origin,bearingDegrees

exclude list

Return all fields except these (comma-separated).

example: exclude=radiusMeters

pretty boolean

Pretty-print the JSON response.

default: false

example: pretty=true

unwrap boolean

Drop the envelope: return the raw array/object without data/meta wrapper.

default: false

example: unwrap=true

Response schema Fields returned in each record 7

Field	Type	Description	Example
`origin`	object	Canonical start coordinate.	{"latitude":55.6761,"longitude":12.5683}
`bearingDegrees`	float	Canonical initial bearing in [0, 360).	90
`distanceKilometers`	float	Requested spherical arc distance in kilometers.	1000
`destination`	object	Calculated coordinate with longitude normalized to [-180, 180).	{"latitude":55.002,"longitude":28.227}
`finalBearingDegrees` nullable	float	Forward bearing at the destination; null for zero distance or a polar destination where local north is undefined.	102.8
`model`	string	Explicit calculation model: mean-earth-sphere (not an ellipsoidal or road distance).	mean-earth-sphere
`radiusMeters`	float	IUGG mean Earth radius used by every calculation, in meters.	6371008.8

origin object

Canonical start coordinate.

example: {"latitude":55.6761,"longitude":12.5683}

bearingDegrees float

Canonical initial bearing in [0, 360).

example: 90

distanceKilometers float

Requested spherical arc distance in kilometers.

example: 1000

destination object

Calculated coordinate with longitude normalized to [-180, 180).

example: {"latitude":55.002,"longitude":28.227}

finalBearingDegrees float nullable

Forward bearing at the destination; null for zero distance or a polar destination where local north is undefined.

example: 102.8

model string

Explicit calculation model: mean-earth-sphere (not an ellipsoidal or road distance).

example: mean-earth-sphere

radiusMeters float

IUGG mean Earth radius used by every calculation, in meters.

example: 6371008.8

Documented examples

Build-generated requests and complete responses 3

One thousand kilometers east of Copenhagen /api/geodesy/destination?lat=55.6761&lon=12.5683&bearing=90&distanceKm=1000

GET /api/geodesy/destination?lat=55.6761&lon=12.5683&bearing=90&distanceKm=1000

{
  "data": {
    "origin": {
      "latitude": 55.6761,
      "longitude": 12.5683
    },
    "bearingDegrees": 90,
    "distanceKilometers": 1000,
    "destination": {
      "latitude": 54.657697998,
      "longitude": 28.246258981
    },
    "finalBearingDegrees": 102.895471621,
    "model": "mean-earth-sphere",
    "radiusMeters": 6371008.8
  },
  "meta": {
    "endpoint": "geodesy",
    "route": "/destination",
    "params": {
      "lat": 55.6761,
      "lon": 12.5683,
      "bearing": 90,
      "distanceKm": 1000
    },
    "generatedAt": "2026-07-30T15:14:08.000Z"
  }
}

Cross the antimeridian /api/geodesy/destination?lat=0&lon=179&bearing=90&distanceKm=500

GET /api/geodesy/destination?lat=0&lon=179&bearing=90&distanceKm=500

{
  "data": {
    "origin": {
      "latitude": 0,
      "longitude": 179
    },
    "bearingDegrees": 90,
    "distanceKilometers": 500,
    "destination": {
      "latitude": 0,
      "longitude": -176.503398181
    },
    "finalBearingDegrees": 90,
    "model": "mean-earth-sphere",
    "radiusMeters": 6371008.8
  },
  "meta": {
    "endpoint": "geodesy",
    "route": "/destination",
    "params": {
      "lat": 0,
      "lon": 179,
      "bearing": 90,
      "distanceKm": 500
    },
    "generatedAt": "2026-07-30T15:14:08.000Z"
  }
}

Zero-distance identity /api/geodesy/destination?lat=-33.8688&lon=151.2093&bearing=42&distanceKm=0

GET /api/geodesy/destination?lat=-33.8688&lon=151.2093&bearing=42&distanceKm=0

{
  "data": {
    "origin": {
      "latitude": -33.8688,
      "longitude": 151.2093
    },
    "bearingDegrees": 42,
    "distanceKilometers": 0,
    "destination": {
      "latitude": -33.8688,
      "longitude": 151.2093
    },
    "finalBearingDegrees": null,
    "model": "mean-earth-sphere",
    "radiusMeters": 6371008.8
  },
  "meta": {
    "endpoint": "geodesy",
    "route": "/destination",
    "params": {
      "lat": -33.8688,
      "lon": 151.2093,
      "bearing": 42,
      "distanceKm": 0
    },
    "generatedAt": "2026-07-30T15:14:08.000Z"
  }
}

GET /api/geodesy/bbox Calculate a spherical radius bounding box with explicit dateline and pole behavior Computed answer

Live requestRuns against the public API

No key required

GET/api/geodesy/bbox?lat=55.6761&lon=12.5683&radiusKm=100

Request parameters

latrequired

Latitude in WGS 84 decimal degrees, from -90 to 90 inclusive.

lonrequired

Longitude in WGS 84 decimal degrees, from -180 to 180 inclusive; +180 canonicalizes to -180.

radiusKmrequired

Spherical radius in kilometers, 0–40031. A radius reaching either pole spans all longitudes.

Advanced response options4 options

fields

Return only these fields (comma-separated). Mutually exclusive with 'exclude'.

exclude

Return all fields except these (comma-separated).

prettydefault false

Pretty-print the JSON response.

unwrapdefault false

Drop the envelope: return the raw array/object without data/meta wrapper.

Response

Example parameters are ready. Send the request to inspect the live response.

Route reference

Code, request parameters, response fields and verified examples 7 params · 10 fields · 3 examples

Code samples Ready-to-copy requests in 4 languages

curl JavaScript Python PHP

curl "https://randomapi.dev/api/geodesy/bbox?lat=55.6761&lon=12.5683&radiusKm=100"

const res = await fetch("https://randomapi.dev/api/geodesy/bbox?lat=55.6761&lon=12.5683&radiusKm=100");
const { data, meta } = await res.json();

import requests

data = requests.get("https://randomapi.dev/api/geodesy/bbox?lat=55.6761&lon=12.5683&radiusKm=100").json()["data"]

$json = json_decode(file_get_contents(
  "https://randomapi.dev/api/geodesy/bbox?lat=55.6761&lon=12.5683&radiusKm=100"
), true);
$data = $json["data"];

Parameters Route-specific request inputs 3

Parameter	Type	Default & allowed	Description
`lat` required	float	allowed: -90 – 90 example: 55.6761	Latitude in WGS 84 decimal degrees, from -90 to 90 inclusive.
`lon` required	float	allowed: -180 – 180 example: 12.5683	Longitude in WGS 84 decimal degrees, from -180 to 180 inclusive; +180 canonicalizes to -180.
`radiusKm` required	float	allowed: 0 – 40031 example: 100	Spherical radius in kilometers, 0–40031. A radius reaching either pole spans all longitudes.

lat float required

Latitude in WGS 84 decimal degrees, from -90 to 90 inclusive.

allowed: -90 – 90

example: lat=55.6761

lon float required

Longitude in WGS 84 decimal degrees, from -180 to 180 inclusive; +180 canonicalizes to -180.

allowed: -180 – 180

example: lon=12.5683

radiusKm float required

Spherical radius in kilometers, 0–40031. A radius reaching either pole spans all longitudes.

allowed: 0 – 40031

example: radiusKm=100

Universal parameters Shared response and formatting options 4

Parameter	Type	Default & allowed	Description
`fields`	list	example: center,radiusKilometers	Return only these fields (comma-separated). Mutually exclusive with 'exclude'.
`exclude`	list	example: radiusMeters	Return all fields except these (comma-separated).
`pretty`	boolean	default: false example: true	Pretty-print the JSON response.
`unwrap`	boolean	default: false example: true	Drop the envelope: return the raw array/object without data/meta wrapper.

fields list

Return only these fields (comma-separated). Mutually exclusive with 'exclude'.

example: fields=center,radiusKilometers

exclude list

Return all fields except these (comma-separated).

example: exclude=radiusMeters

pretty boolean

Pretty-print the JSON response.

default: false

example: pretty=true

unwrap boolean

Drop the envelope: return the raw array/object without data/meta wrapper.

default: false

example: unwrap=true

Response schema Fields returned in each record 10

Field	Type	Description	Example
`center`	object	Canonical center coordinate.	{"latitude":55.6761,"longitude":12.5683}
`radiusKilometers`	float	Requested spherical radius in kilometers.	100
`south`	float	Minimum latitude, clamped to -90.	54.7768
`north`	float	Maximum latitude, clamped to 90.	56.5754
`west`	float	Western longitude; greater than east when the box crosses the antimeridian.	10.98
`east`	float	Eastern longitude; less than west when the box crosses the antimeridian.	14.15
`crossesAntimeridian`	boolean	True when the longitude interval wraps across ±180 degrees.	false
`spansAllLongitudes`	boolean	True when the radius reaches a pole or covers the full globe.	false
`model`	string	Explicit calculation model: mean-earth-sphere (not an ellipsoidal or road distance).	mean-earth-sphere
`radiusMeters`	float	IUGG mean Earth radius used by every calculation, in meters.	6371008.8

center object

Canonical center coordinate.

example: {"latitude":55.6761,"longitude":12.5683}

radiusKilometers float

Requested spherical radius in kilometers.

example: 100

south float

Minimum latitude, clamped to -90.

example: 54.7768

north float

Maximum latitude, clamped to 90.

example: 56.5754

west float

Western longitude; greater than east when the box crosses the antimeridian.

example: 10.98

east float

Eastern longitude; less than west when the box crosses the antimeridian.

example: 14.15

crossesAntimeridian boolean

True when the longitude interval wraps across ±180 degrees.

example: false

spansAllLongitudes boolean

True when the radius reaches a pole or covers the full globe.

example: false

model string

Explicit calculation model: mean-earth-sphere (not an ellipsoidal or road distance).

example: mean-earth-sphere

radiusMeters float

IUGG mean Earth radius used by every calculation, in meters.

example: 6371008.8

Documented examples

Build-generated requests and complete responses 3

One-hundred-kilometer Copenhagen box /api/geodesy/bbox?lat=55.6761&lon=12.5683&radiusKm=100

GET /api/geodesy/bbox?lat=55.6761&lon=12.5683&radiusKm=100

{
  "data": {
    "center": {
      "latitude": 55.6761,
      "longitude": 12.5683
    },
    "radiusKilometers": 100,
    "south": 54.776779636,
    "north": 56.575420364,
    "west": 10.973253875,
    "east": 14.163346125,
    "crossesAntimeridian": false,
    "spansAllLongitudes": false,
    "model": "mean-earth-sphere",
    "radiusMeters": 6371008.8
  },
  "meta": {
    "endpoint": "geodesy",
    "route": "/bbox",
    "params": {
      "lat": 55.6761,
      "lon": 12.5683,
      "radiusKm": 100
    },
    "generatedAt": "2026-07-30T15:14:08.000Z"
  }
}

Antimeridian-crossing box /api/geodesy/bbox?lat=0&lon=179&radiusKm=500

GET /api/geodesy/bbox?lat=0&lon=179&radiusKm=500

{
  "data": {
    "center": {
      "latitude": 0,
      "longitude": 179
    },
    "radiusKilometers": 500,
    "south": -4.496601819,
    "north": 4.496601819,
    "west": 174.503398181,
    "east": -176.503398181,
    "crossesAntimeridian": true,
    "spansAllLongitudes": false,
    "model": "mean-earth-sphere",
    "radiusMeters": 6371008.8
  },
  "meta": {
    "endpoint": "geodesy",
    "route": "/bbox",
    "params": {
      "lat": 0,
      "lon": 179,
      "radiusKm": 500
    },
    "generatedAt": "2026-07-30T15:14:08.000Z"
  }
}

North-pole-reaching box /api/geodesy/bbox?lat=89&lon=30&radiusKm=500

GET /api/geodesy/bbox?lat=89&lon=30&radiusKm=500

{
  "data": {
    "center": {
      "latitude": 89,
      "longitude": 30
    },
    "radiusKilometers": 500,
    "south": 84.503398181,
    "north": 90,
    "west": -180,
    "east": 180,
    "crossesAntimeridian": false,
    "spansAllLongitudes": true,
    "model": "mean-earth-sphere",
    "radiusMeters": 6371008.8
  },
  "meta": {
    "endpoint": "geodesy",
    "route": "/bbox",
    "params": {
      "lat": 89,
      "lon": 30,
      "radiusKm": 500
    },
    "generatedAt": "2026-07-30T15:14:08.000Z"
  }
}

About this API

Coverage, behavior and common use cases

Coverage & behavior

Pure spherical geodesy for coordinate work: great-circle distance and bearings, a destination from bearing plus distance, and a radius bounding box. Inputs use WGS 84 latitude/longitude order and ranges, while the calculation surface is an explicitly documented sphere with the IUGG mean Earth radius 6,371,008.8 metres.

This honesty matters: the endpoint does not claim ellipsoidal survey precision, road distance, flight routing, terrain clearance or uncertainty inferred from decimal digits. The response always includes model: "mean-earth-sphere" and radiusMeters, so callers can decide whether the approximation fits their use case.

/distance returns central angle, distance, initial/final bearings, and explicit coincident/antipodal flags. Bearings are null where a unique direction or local north reference does not exist (coincident/antipodal geometry and the relevant geographic pole).
/destination follows the great circle from one point for a bearing and non-negative distance, normalizing the result longitude to [-180, 180). A non-zero journey cannot start exactly at a pole because an initial compass bearing has no local-north reference there; that case is an explicit 400.
/bbox returns the smallest latitude/longitude-aligned spherical bounding box for a radius. It exposes antimeridian crossing (west > east) and pole/full-longitude coverage instead of returning a misleading ordinary box.

All calculations are deterministic, synchronous and dataset-free.

Use it for

Estimate great-circle separation and bearings between map markers without a client geospatial library
Compute a destination point for location demos, proximity fixtures and map-camera tests
Build a coarse pre-filter bounding box before a precise distance check, including dateline and pole cases

Frequently asked questions

Practical answers about this endpoint 3

Is the distance an exact WGS 84 ellipsoid distance?

No. Coordinates use WGS 84 ranges, but the calculation uses the exposed IUGG mean-Earth sphere. It is a great-circle approximation, not survey, route or terrain distance.

What happens at coincident or antipodal points?

Distance remains defined, but coincident/antipodal bearings are null. A bearing evaluated at a pole is also null; a non-zero destination journey cannot start at a pole and returns 400.

Can bounding boxes cross the international date line?

Yes. crossesAntimeridian is true and west is greater than east; boxes reaching a pole instead set spansAllLongitudes and use -180 to 180.

Standards & references

Primary sources behind the contract

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GET /api/geodesy/distance Calculate spherical great-circle distance and bearings between two points Computed answer

Request parameters

Response

Route reference

Documented examples

GET /api/geodesy/destination Find the great-circle destination from a point, bearing and distance Computed answer

Request parameters

Response

Route reference

Documented examples

GET /api/geodesy/bbox Calculate a spherical radius bounding box with explicit dateline and pole behavior Computed answer

Request parameters

Response

Route reference

Documented examples

About this API

Coverage & behavior

Use it for

Frequently asked questions

Standards & references

Related APIs