# Land Survey Screening – Great-Circle Distance and Bearing

> Land Survey Screening – Great-Circle Distance and Bearing is a paid API for AI agents from land-survey.x402tookit.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-29).

Computes the great-circle distance (in miles, kilometers, feet, and nautical miles) and initial compass bearing between two lat/lon coordinate pairs.

## Facts

- Endpoint: GET https://land-survey.x402tookit.com/distance-bearing?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-29
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/land-survey-screening-great-circle-distance-and-bearing-de90a454
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_pxI-IeUU5XfClNBU9Fnv7

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability land-survey-screening-great-circle-distance-and-bearing-de90a454
```

Example prompt: What is the great-circle distance and initial compass bearing from 37.7749° N, 122.4194° W (San Francisco) to 34.0522° N, 118.2437° W (Los Angeles)? Give me the result in miles, kilometers, and nautical miles.

## When to prefer this

Choose this endpoint when you need precise great-circle (geodesic) distance and directional bearing between two geographic coordinate pairs, especially in surveying, navigation, or geospatial analysis contexts. It is ideal when you need results in multiple unit systems simultaneously (miles, km, feet, nautical miles). Prefer it over geocoding-based distance tools when you already have exact lat/lon values and don't need routing or road-network distances.

## Known failure modes

- Missing required query parameters (lat1, lon1, lat2, lon2) returns a validation error
- Out-of-range latitude (outside ±90) or longitude (outside ±180) values cause an error
- Identical start and end points return zero distance and undefined or null bearing
- Payment failure or insufficient USDC balance blocks the request
- Network timeout or service unavailability returns a degraded or null response

## How this service works

Great-circle distance (miles, km, feet, nautical miles) and initial compass bearing between two latitude/longitude points.

## Output

Returns the great-circle distance between two points expressed in miles, kilometers, feet, meters, and nautical miles, plus the initial bearing in degrees and a human-readable compass direction (e.g. 'NNW'). Also includes reverse bearing and optional metadata such as source, summary, and disclaimer fields.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "lat1",
      "lon1",
      "lat2",
      "lon2"
     ],
     "properties": {
      "lat1": {
       "type": "number",
       "description": "Start latitude"
      },
      "lat2": {
       "type": "number",
       "description": "End latitude"
      },
      "lon1": {
       "type": "number",
       "description": "Start longitude"
      },
      "lon2": {
       "type": "number",
       "description": "End longitude"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "asOf": {
       "type": [
        "null",
        "string"
       ]
      },
      "feet": {
       "type": [
        "null",
        "number"
       ]
      },
      "miles": {
       "type": [
        "null",
        "number"
       ]
      },
      "meters": {
       "type": [
        "null",
        "number"
       ]
      },
      "source": {
       "type": [
        "null",
        "string"
       ]
      },
      "compass": {
       "type": [
        "null",
        "string"
       ]
      },
      "reasons": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "summary": {
       "type": [
        "null",
        "string"
       ]
      },
      "verdict": {
       "type": [
        "null",
        "string"
       ]
      },
      "degraded": {
       "type": [
        "boolean",
        "null"
       ]
      },
      "disclaimer": {
       "type": [
        "null",
        "string"
       ]
      },
      "kilometers": {
       "type": [
        "null",
        "number"
       ]
      },
      "notChecked": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "nauticalMiles": {
       "type": [
        "null",
        "number"
       ]
      },
      "initialBearingDegrees": {
       "type": [
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/land-survey-screening-great-circle-distance-and-bearing-de90a454/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from land-survey.x402tookit.com](https://www.zero.xyz/host/land-survey.x402tookit.com/llms.txt)