<!--
{
  "availability" : [
    "iOS: 14.0.0 -",
    "iPadOS: 14.0.0 -"
  ],
  "documentType" : "symbol",
  "framework" : "ARKit",
  "identifier" : "/documentation/ARKit/ARGeoAnchor/AltitudeSource-swift.enum/userDefined",
  "metadataVersion" : "0.1.0",
  "role" : "Case",
  "symbol" : {
    "kind" : "Case",
    "modules" : [
      "ARKit"
    ],
    "preciseIdentifier" : "c:@E@ARAltitudeSource@ARAltitudeSourceUserDefined"
  },
  "title" : "ARGeoAnchor.AltitudeSource.userDefined"
}
-->

# ARGeoAnchor.AltitudeSource.userDefined

The app defines the altitude.

```
case userDefined
```

## Discussion

ARKit records this altitude source when your app defines a geo anchor’s altitude.

You may acquire altitude by providing a particular scene coordinate to the session using [`getGeoLocation(forPoint:completionHandler:)`](/documentation/ARKit/ARSession/getGeoLocation(forPoint:completionHandler:)).

For example, your app might set a geo anchor’s altitude by raycasting a surface, then adding an arbitrary `y-`amount to make the anchor more visible from afar.

---

Copyright &copy; 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)