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VPSLocationSource

wemap-sdk-js

Class: VPSLocationSource

LocationSource that combines VPS positioning with PDR and attitude tracking

This source provides:

  • VPS: Visual positioning using camera (provides position and attitude)
  • PDR: Pedestrian Dead Reckoning via AbsolutePositionProvider (provides continuous position updates)
  • AbsoluteAttitude: Device orientation tracking

VPS (Visual Positioning System) uses the device camera to identify the user's location by matching visual features. After an initial VPS scan, PDR provides continuous position updates as the user moves.

Example​

import { VPSLocationSource } from '@wemap/positioning';

const vpsSource = new VPSLocationSource({
  usePositionSmoother: true
});

vpsSource.onUpdate((pose) => {
  console.log('Position:', pose.position);
  console.log('Attitude:', pose.attitude);
});

await vpsSource.start();

// Start VPS scan (requires camera access)
const scanSuccess = await vpsSource.startScan();
if (scanSuccess) {
  console.log('VPS scan successful!');
}

Extends​

Constructors​

Constructor​

new VPSLocationSource(config): VPSLocationSource

Parameters​

config​

VPSLocationSourceConfig = {}

Returns​

VPSLocationSource

Overrides​

LocationSource.constructor

Properties​

isStarted​

isStarted: boolean = false

Inherited from​

LocationSource.isStarted

scanStatus​

scanStatus: "scanning" | "stopped" = 'stopped'

Methods​

offError()​

offError(callback): void

Remove the error callback

Parameters​

callback​

(error) => void

The callback function to remove

Returns​

void

Inherited from​

LocationSource.offError

offUpdate()​

offUpdate(callback): void

Remove the update callback

Parameters​

callback​

(data) => void

The callback function to remove

Returns​

void

Inherited from​

LocationSource.offUpdate

onError()​

onError(callback): void

Register a callback to receive error events

Parameters​

callback​

(error) => void

Function to call when an error occurs

Returns​

void

Inherited from​

LocationSource.onError

onUpdate()​

onUpdate(callback): void

Register a callback to receive pose updates

The callback receives complete pose data. If there's already a current pose available, the callback will be called immediately with that data.

Parameters​

callback​

(data) => void

Function to call when pose data is updated

Returns​

void

Example​

locationSource.onUpdate((pose) => {
  console.log('Current pose:', pose);
});

Inherited from​

LocationSource.onUpdate

start()​

start(): Promise\<void>

Start the location source and begin emitting updates

Returns​

Promise\<void>

Overrides​

LocationSource.start

startScan()​

startScan(): Promise\<boolean>

Start the VPS scan

Initiates a visual positioning scan using the device camera. This should be called when the user wants to determine their initial position. The scan will continue until a successful match is found or an error occurs.

Note: This requires camera permissions and the user should point the camera at recognizable visual features in the environment.

Returns​

Promise\<boolean>

Promise that resolves to true if the scan was successful, false otherwise

Throws​

If VPS is not available or endpoint is not configured

Example​

await vpsSource.start();
const success = await vpsSource.startScan();
if (success) {
  console.log('Position found via VPS!');
} else {
  console.log('VPS scan failed');
}

stop()​

stop(): Promise\<void>

Stop the location source and stop emitting updates

Returns​

Promise\<void>

Overrides​

LocationSource.stop

stopScan()​

stopScan(): Promise\<void>

Stop the VPS scan

Stops an active VPS scan and releases camera resources.

Returns​

Promise\<void>

Example​

await vpsSource.stopScan();