# trackAnchor

Source: https://www.nianticspatial.com/docs/api/swift/NSDK.NSDKVps2Session.method-trackAnchor/

trackAnchor

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## Declaration

func trackAnchor(payload: String) throws -> NSDKVpsAnchorId

#### Summary

Requests to start tracking an anchor specified by a payload.
A VPS payload contains all the data needed to localize at a VPS-activated location.
A default payload for a VPS-activated location can be obtained from the "blob" field
in the details view of an entry in the Geospatial Browser, or via
anchorPayload(anchorId:) for user-generated anchors.
The returned anchor ID is automatically polled each frame via update(), and updates
are published on anchorUpdated.

#### Returns

The unique identifier of the anchor encoded in the payload.

#### Throws

NSDKError.invalidArgument if the payload is not valid.

### Parameters

| Name | Type | Summary |
| --- | --- | --- |
| payload | String | Base64-encoded anchor payload. |

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