> ## Documentation Index
> Fetch the complete documentation index at: https://astral-6ef288be-claude-ascii-globe-mouse-interaction-bupya.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# POST /distance

> Calculate distance between two geometries

<Warning>
  **Research Preview** — This API is under development.
</Warning>

# Distance

Calculate the distance between two geometries in meters.

```
POST /compute/v0/distance
```

## Request Body

<ParamField body="chainId" type="number" required>
  Target chain ID. All UIDs must exist on this chain.
</ParamField>

<ParamField body="from" type="Input" required>
  First geometry. Can be a UID, GeoJSON, or offchain attestation reference.
</ParamField>

<ParamField body="to" type="Input" required>
  Second geometry. Can be a UID, GeoJSON, or offchain attestation reference.
</ParamField>

<ParamField body="schema" type="string" required>
  EAS schema UID to issue the attestation against.
</ParamField>

<ParamField body="recipient" type="string">
  Ethereum address to receive the attestation. Defaults to zero address if not provided.
</ParamField>

## Example Request

<CodeGroup>
  ```bash cURL theme={null}
  curl -X POST https://api.astral.global/compute/v0/distance \
    -H "Content-Type: application/json" \
    -d '{
      "chainId": 84532,
      "from": "0xabc123...",
      "to": {
        "type": "Point",
        "coordinates": [2.2945, 48.8584]
      },
      "schema": "0xschema...",
      "recipient": "0xdef456..."
    }'
  ```

  ```typescript TypeScript theme={null}
  const response = await fetch('https://api.astral.global/compute/v0/distance', {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({
      chainId: 84532,
      from: '0xabc123...',
      to: { type: 'Point', coordinates: [2.2945, 48.8584] },
      schema: '0xschema...',
      recipient: '0xdef456...'
    })
  });

  const result = await response.json();
  ```
</CodeGroup>

## Response

<ResponseField name="result" type="number" required>
  Distance in meters (e.g., 523.45)
</ResponseField>

<ResponseField name="units" type="string" required>
  Always "meters"
</ResponseField>

<ResponseField name="operation" type="string" required>
  Always "distance"
</ResponseField>

<ResponseField name="timestamp" type="number" required>
  Unix timestamp of computation
</ResponseField>

<ResponseField name="inputRefs" type="string[]" required>
  Array of input references (UIDs or geometry hashes)
</ResponseField>

<ResponseField name="attestation" type="object" required>
  The signed attestation object
</ResponseField>

<ResponseField name="delegatedAttestation" type="object" required>
  Signature for delegated onchain submission
</ResponseField>

## Example Response

```json theme={null}
{
  "result": 523.45,
  "units": "meters",
  "operation": "distance",
  "timestamp": 1706400000,
  "inputRefs": [
    "0xabc123...",
    "0x7d3e8f..."
  ],
  "attestation": {
    "schema": "0x...",
    "attester": "0x...",
    "recipient": "0xdef456...",
    "data": "0x...",
    "signature": "0x..."
  },
  "delegatedAttestation": {
    "signature": "0x...",
    "attester": "0x...",
    "deadline": 1706403600
  }
}
```

## Notes

* Distance is calculated using PostGIS `ST_Distance` with geodetic coordinates
* Result is in meters with centimeter precision (rounded to 0.01m)
* For raw GeoJSON inputs, a keccak256 hash is used in `inputRefs`

<Card title="SDK Method" icon="code" href="/sdk/compute#distance">
  See `astral.compute.distance()`
</Card>