API Documentation

Aerodrome safeguarding surfaces generation — ICAO Annex 14 OLS, OFS, OES, and ICAO EUR DOC 015 BRA. All endpoints return GeoJSON.

Endpoints

POST

/api/v1/ols/calculate

Obstacle Limitation Surfaces (ICAO/EASA)

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POST

/api/v1/ofs/calculate

Obstacle Free Surfaces (ICAO)

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POST

/api/v1/oes/calculate

Obstacle Evaluation Surfaces (ICAO)

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POST

/api/v1/bra/calculate

Building Restricted Areas (ICAO)

View docs

Authentication

Authorization: Bearer aoi_xxxxxxxxxxxxxxxxxxxxxxxx
Content-Type: application/json

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OLS — Obstacle Limitation Surfaces

Generates ICAO Annex 14 or EASA obstacle limitation surfaces for one or more runways. Surfaces include outer horizontal, conical, inner horizontal, approach, takeoff, transitional, and precision-only surfaces.

Top-Level Fields

Field	Type	Req	Notes
standard	string	Yes	"icao" or "easa"
airport	object	Yes	Airport object (see below)
runways	array	Yes	One or more runway objects

Airport Object

Field	Type	Req	Notes
epsgCode / epsgcode	number	Yes	EPSG projection code
arplat	number	Yes	ARP latitude (decimal degrees)
arplng	number	Yes	ARP longitude (decimal degrees)
arpelev	number	Yes	ARP elevation (metres)
ihsdatum	number	Yes	Inner horizontal surface datum (metres)
ohsradius	number	No	Outer horizontal surface radius override

Runway Object — Required

Field	Type	Req	Notes
name / rwyname	string	Yes	Runway designator, e.g. "04"
rwyclass	string	Yes	See valid values below
rwycode	number	Yes	ICAO runway code: 1, 2, 3, or 4
rwyalat	number	Yes	Threshold A latitude
rwyalng	number	Yes	Threshold A longitude
rwyaelev	number	Yes	Threshold A elevation (metres)
rwyblat	number	Yes	Threshold B latitude
rwyblng	number	Yes	Threshold B longitude
rwybelev	number	Yes	Threshold B elevation (metres)
acMassAbove5700kg	boolean	Yes	Aircraft mass above 5700 kg
codeF	boolean	Yes	Code F aircraft operations
imcVmcNightTakeoff	boolean	Yes	IMC/VMC night takeoff
takeoffSlope16Percent	boolean	Yes	1.6% takeoff slope applies

Runway Object — Optional

Field	Type	Req	Notes
cwylength	number	No	Clearway length (metres)
cwyelev	number	No	Clearway elevation (metres)
appobstelev	number	No	Approach obstacle elevation (metres)
profilePoints	array	No	Runway profile points along runway

Valid rwyclass values

"Non-Instrument"

"Non-Precision Approach"

"Precision Approach CAT I"

"Precision Approach CAT II"

"Precision Approach CAT III"

Output Surfaces

Outer HorizontalConicalInner HorizontalTransitionalApproachTakeoffInner TransitionalInner ApproachBalked LandingStrip

Example Payload

{
  "standard": "icao",
  "airport": {
    "epsgcode": 32651,
    "arplat": 10.30756272,
    "arplng": 123.97943972,
    "arpelev": 8.0,
    "ihsdatum": 45.0
  },
  "runways": [
    {
      "rwyname": "04",
      "rwyclass": "Precision Approach CAT I",
      "rwycode": 4,
      "rwyalat": 10.29695142,
      "rwyalng": 123.96878489,
      "rwyaelev": 6.49,
      "rwyblat": 10.31618992,
      "rwyblng": 123.98810064,
      "rwybelev": 9.43,
      "acMassAbove5700kg": true,
      "codeF": false,
      "imcVmcNightTakeoff": false,
      "takeoffSlope16Percent": false,
      "appobstelev": 250,
      "cwylength": 150,
      "cwyelev": 9.43,
      "profilePoints": [
        { "distance": 300, "elevation": 7 },
        { "distance": 600, "elevation": 8 }
      ]
    }
  ]
}

OFS — Obstacle Free Surfaces

Generates ICAO obstacle-free zone surfaces for one or more runways. Precision-only surfaces (Inner Approach, Inner Transitional, Balked Landing) are only generated when rwyclass contains "precision" (case-insensitive).

Airport Object

Field	Type	Req	Notes
epsgCode / epsgcode	number	Yes	EPSG projection code
arplat	number	Yes	ARP latitude
arplng	number	Yes	ARP longitude
arpelev	number	Yes	ARP elevation (metres)

Runway Object — Required

Field	Type	Req	Notes
name / rwyname	string	Yes	Runway designator
rwyclass	string	Yes	See valid values
rwyadg	string	Yes	ADG classification
rwyalat / rwyblat	number	Yes	Threshold lat/lng/elev (A and B)
rwyWidth	number	Yes	Runway width (metres)
acMassAbove5700kg	boolean	Yes	Aircraft mass above 5700 kg
codeF	boolean	Yes	Code F aircraft operations
imcVmcNightTakeoff	boolean	Yes	IMC/VMC night takeoff
takeoffSlope16Percent	boolean	Yes	1.6% takeoff slope applies

Runway Object — Optional

Field	Type	Req	Notes
och	number	No	Obstacle clearance height (metres)
cwylength	number	No	Clearway length (metres)
profilePoints	array	No	Runway profile points

Output Surfaces

ApproachTransitionalTakeoffInner ApproachInner TransitionalBalked Landing

Example Payload

{
  "airport": {
    "epsgcode": 32651,
    "arplat": 10.30756272,
    "arplng": 123.97943972,
    "arpelev": 8.0
  },
  "runways": [
    {
      "rwyname": "04",
      "rwyclass": "Precision Approach CAT I",
      "rwyadg": "IV",
      "rwyalat": 10.29695142,
      "rwyalng": 123.96878489,
      "rwyaelev": 6.49,
      "rwyblat": 10.31618992,
      "rwyblng": 123.98810064,
      "rwybelev": 9.43,
      "acMassAbove5700kg": true,
      "codeF": false,
      "imcVmcNightTakeoff": false,
      "takeoffSlope16Percent": false,
      "rwyWidth": 45,
      "och": 50,
      "appobstelev": 250,
      "cwylength": 150
    }
  ]
}

OES — Obstacle Evaluation Surfaces

Generates FAA/ICAO obstacle evaluation surfaces. The request body contains a surfaces array where each entry describes one surface type for one runway.

Top-Level Fields

Field	Type	Req	Notes
airport	object	Yes	Airport object
surfaces	array	Yes	Array of surface definition objects

Airport Object

Field	Type	Req	Notes
epsgCode / epsgcode	number	Yes	EPSG projection code
arplat	number	Yes	ARP latitude
arplng	number	Yes	ARP longitude
arpelev	number	Yes	ARP elevation (metres)

Surface Definition Object

Field	Type	Req	Notes
type	string	Yes	Surface type (see valid values)
runway	object	Yes	Runway object
adgGroups	string[]	No	Required when type is "horizontal"
criteriaKey	string	No	Required for all other types

Valid surface "type" values

"horizontal"— ADG group horizontal surfaces

"straight_in_instrument"— criteriaKey: "I-V"

"instrument_departure"— criteriaKey: "I_to_V"

"precision_approach"— criteriaKey: "I_to_V"

Valid adgGroups values

"ADG I-IIA"

"ADG IIB"

"ADG IIC-V"

Output Surfaces

Horizontal surface ADG I-IIAHorizontal surface ADG IIBHorizontal surface ADG IIC-VSurface for straight-in instrument approachesInstrument departure surfaceSurface for precision approaches

Example Payload

{
  "airport": {
    "epsgcode": 32651,
    "arplat": 10.30756272,
    "arplng": 123.97943972,
    "arpelev": 8.0
  },
  "surfaces": [
    {
      "type": "horizontal",
      "adgGroups": ["ADG I-IIA", "ADG IIB", "ADG IIC-V"],
      "runway": {
        "rwyname": "04",
        "rwyalat": 10.29695142,
        "rwyalng": 123.96878489,
        "rwyaelev": 6.49,
        "rwyblat": 10.31618992,
        "rwyblng": 123.98810064,
        "rwybelev": 9.43
      }
    },
    {
      "type": "straight_in_instrument",
      "criteriaKey": "I-V",
      "runway": {
        "rwyname": "04",
        "rwyalat": 10.29695142,
        "rwyalng": 123.96878489,
        "rwyaelev": 6.49,
        "rwyblat": 10.31618992,
        "rwyblng": 123.98810064,
        "rwybelev": 9.43
      }
    }
  ]
}

BRA — Building Restricted Areas

Generates NAVAID building restriction areas. Supports two modes: omnidirectional (cylindrical + cone) and unidirectional (rectangular + trapezoidal + arc). Set the top-level type field to select the mode.

Navaid Object (all BRA types)

Field	Type	Req	Notes
ident	string	Yes	NAVAID identifier, e.g. "MCT"
type	string	Yes	NAVAID type key (see tables below)
lat	number	Yes	Latitude (decimal degrees)
lng	number	Yes	Longitude (decimal degrees)
antennaAltGroundLevel	number	Yes	Antenna elevation above ground (metres)
epsgCode / epsgcode	number	Yes	EPSG projection code

Omnidirectional

Set "type": "omnidirectional" at the top level.

navaid.type values

cvor— Conventional VOR

dvor— Doppler VOR

df— Direction Finder

dmen— DME (Non-directional)

ndb— NDB

marker— Marker Beacon

gbas-r— GBAS Reference

psr— Primary Surveillance Radar

ssr— Secondary Surveillance Radar

params

Field	Type	Req	Notes
evaluateForWindTurbines	boolean	Yes	Generates Second Cylinder for cvor/dvor/df
radiusCylinder	number	No	First cylinder radius (metres)
alphaCone	number	No	Cone half-angle (degrees)
radiusCone	number	No	Cone base radius (metres)

Output Surfaces

First CylinderSecond CylinderCone

Example

{
  "type": "omnidirectional",
  "navaid": {
    "ident": "MCT",
    "type": "dvor",
    "lat": 10.3135675,
    "lng": 123.98829611,
    "antennaAltGroundLevel": 10.14,
    "epsgcode": 32651
  },
  "params": {
    "evaluateForWindTurbines": false,
    "radiusCylinder": 600,
    "alphaCone": 1.0,
    "radiusCone": 3000
  }
}

Unidirectional

Set "type": "unidirectional". Criteria are resolved automatically from ICAO BRA criteria.

navaid.type values

ilsllz-1— ILS LLZ Single FRQ

ilsllz-2— ILS LLZ Dual FRQ

mls-az— MLS AZ

dme-d— DME (Directional)

ilsgp-m— ILS GP-M Dual FRQ

mls-el— MLS EL

params

Field	Type	Req	Notes
direction	number	Yes	Bearing from NAVAID (degrees true, 0–360)
distanceToThreshold	number	No	Distance to runway threshold (metres). Required for ilsllz-1/2, mls-az, dme-d

Output Surfaces

RectangleRight TrapezoidLeft TrapezoidArc Surface

Example — ILS LLZ

{
  "type": "unidirectional",
  "navaid": {
    "ident": "ILS LLZ",
    "type": "ilsllz-2",
    "lat": 10.3135675,
    "lng": 123.98829611,
    "antennaAltGroundLevel": 10.14,
    "epsgcode": 32651
  },
  "params": {
    "direction": 44,
    "distanceToThreshold": 2818
  }
}

Response Format

All endpoints return a GeoJSON FeatureCollection with 3D coordinates (lng, lat, elevation). Each feature carries metadata about the surface it represents.

Success Response

{
  "type": "FeatureCollection",
  "properties": {
    "epsgCode": 32651
  },
  "features": [
    {
      "type": "Feature",
      "properties": {
        "id": "04_approach",
        "runway": "04",
        "surface": "Approach",
        "group": "Approach",
        "category": "surface"
      },
      "geometry": {
        "type": "MultiPolygon",
        "coordinates": [ ... ]
      }
    }
  ]
}

Error Response

{
  "error": {
    "code": "INVALID_INPUT",
    "message": "Validation failed",
    "details": [
      {
        "field": "params.evaluateForWindTurbines",
        "message": "Required"
      }
    ]
  }
}

Status	Code	Meaning
200	—	Success
400	INVALID_INPUT	Validation failed — check details
401	UNAUTHORIZED	Missing or invalid API key
402	PAYMENT_REQUIRED	Insufficient credits
500	SERVER_ERROR	Internal calculation error