> ## 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 /length

> Calculate length of a line

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

# Length

Calculate the length of a line in meters.

```
POST /compute/v0/length
```

## Request Body

<ParamField body="chainId" type="number" required>
  Target chain ID (e.g., 84532 for Base Sepolia, 8453 for Base).
</ParamField>

<ParamField body="geometry" type="Input" required>
  The line geometry to measure.
</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

```bash theme={null}
curl -X POST https://api.astral.global/compute/v0/length \
  -H "Content-Type: application/json" \
  -d '{
    "chainId": 84532,
    "geometry": "0xline...",
    "schema": "0xschema...",
    "recipient": "0xdef456..."
  }'
```

## Example Response

```json theme={null}
{
  "result": 2345.67,
  "units": "meters",
  "operation": "length",
  "timestamp": 1706400000,
  "inputRefs": [
    "0xline..."
  ],
  "attestation": {
    "schema": "0x...",
    "attester": "0x...",
    "recipient": "0xdef456...",
    "data": "0x...",
    "signature": "0x..."
  },
  "delegatedAttestation": {
    "signature": "0x...",
    "attester": "0x...",
    "deadline": 1706403600
  }
}
```

## Notes

* Uses PostGIS `ST_Length` function with geodetic calculation
* Result is in meters with centimeter precision
* Valid for LineString and MultiLineString geometries

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