> ## Documentation Index > Fetch the complete documentation index at: https://docs.mentraglass.com/llms.txt > Use this file to discover all available pages before exploring further. # Location > Access user's GPS location from smart glasses Access the user's GPS coordinates to build location-aware apps on MentraOS using the `LocationManager`. ## Quick Start ### Subscribe to Location Stream Get continuous location updates as the user moves: ```typescript theme={null} protected async onSession(session: AppSession, sessionId: string, userId: string) { // Subscribe to continuous location updates const unsubscribe = session.location.subscribeToStream( { accuracy: "standard" }, (data) => { const { latitude, longitude, accuracy } = data; session.logger.info(`Location: ${latitude}, ${longitude}, accuracy: ${accuracy}m`); } ); // Cleanup when done // unsubscribe(); } ``` ### Get Latest Location (One-Time Poll) Request a single location fix without subscribing to a stream: ```typescript theme={null} protected async onSession(session: AppSession, sessionId: string, userId: string) { try { const location = await session.location.getLatestLocation({ accuracy: "high" }); session.logger.info(`Got location: ${location.latitude}, ${location.longitude}`); } catch (error) { session.logger.error("Failed to get location:", error); } } ``` *** ## LocationManager API The SDK provides `session.location` with three main methods: | Method | Parameters | Returns | Description | | ------------------------------------- | -------------------------------------------------------- | ------------------------------- | ------------------------------------------ | | `subscribeToStream(options, handler)` | `{ accuracy: string }`, `(data: LocationUpdate) => void` | `() => void` (cleanup function) | Subscribe to continuous location updates | | `unsubscribeFromStream()` | None | `void` | Unsubscribe from the location stream | | `getLatestLocation(options)` | `{ accuracy: string }` | `Promise` | One-time location poll (15 second timeout) | *** ## Accuracy Tiers Choose the accuracy tier based on your app's needs. Higher accuracy tiers provide more precise location data but drain more battery. | Accuracy Tier | Description | Update Frequency | Battery Impact | Use Case | | ------------------- | ---------------------------------- | ---------------- | -------------- | ------------------------------ | | `"realtime"` | Highest precision, fastest updates | Very High | High | Navigation, real-time tracking | | `"high"` | High precision GPS | High | Medium-High | Precise location features | | `"tenMeters"` | \~10m accuracy | Medium | Medium | Local place detection | | `"standard"` | Default accuracy (balanced) | Medium | Low-Medium | General location features | | `"hundredMeters"` | \~100m accuracy | Low | Low | City-level features | | `"kilometer"` | \~1km accuracy | Very Low | Very Low | Regional features | | `"threeKilometers"` | \~3km accuracy | Very Low | Very Low | Wide-area features | | `"reduced"` | Battery-saving mode | Minimal | Minimal | Background location | **Example:** ```typescript theme={null} // High accuracy for precise features session.location.subscribeToStream( { accuracy: "high" }, handler ); // Lower accuracy for battery efficiency session.location.subscribeToStream( { accuracy: "hundredMeters" }, handler ); ``` *** ## LocationUpdate Data Structure The `LocationUpdate` interface contains location data: | Field | Type | Required | Description | | --------------- | -------- | -------- | ----------------------------------- | | `latitude` | `number` | ✅ | Latitude in decimal degrees | | `longitude` | `number` | ✅ | Longitude in decimal degrees | | `accuracy` | `number` | ✅ | Accuracy in meters | | `altitude` | `number` | ❌ | Elevation in meters above sea level | | `timestamp` | `Date` | ✅ | When the location was captured | | `correlationId` | `string` | ❌ | Used for tracking poll requests | **TypeScript Interface:** ```typescript theme={null} interface LocationUpdate { latitude: number; longitude: number; accuracy: number; altitude?: number; timestamp: Date; correlationId?: string; } ``` *** ## Usage Examples ### Display Location on Dashboard ```typescript theme={null} protected async onSession(session: AppSession, sessionId: string, userId: string) { session.location.subscribeToStream( { accuracy: "standard" }, (data) => { session.dashboard.content.writeToMain( `Lat: ${data.latitude.toFixed(4)}\n` + `Lon: ${data.longitude.toFixed(4)}\n` + `Accuracy: ${data.accuracy}m` ); } ); } ``` ### Show Location on Voice Command ```typescript theme={null} protected async onToolCall(toolCall: ToolCall): Promise { if (toolCall.toolId === "show_location") { const session = this.getSessionByUserId(toolCall.userId); try { const location = await session.location.getLatestLocation({ accuracy: "high" }); return `Your current location is ${location.latitude.toFixed(4)}, ${location.longitude.toFixed(4)} with ${location.accuracy}m accuracy`; } catch (error) { return "Could not get your current location"; } } } ``` ### Cleanup Subscriptions ```typescript theme={null} protected async onSession(session: AppSession, sessionId: string, userId: string) { const unsubscribe = session.location.subscribeToStream( { accuracy: "standard" }, (data) => { // Handle location updates } ); // Clean up when session ends session.events.on('disconnect', () => { unsubscribe(); }); } ``` *** ## Permissions Location access requires the `location` permission in your app manifest. Configure this in the Developer Console at [console.mentra.glass](https://console.mentra.glass/apps). Users must grant location permission for your app to access GPS data. Always handle cases where location data is unavailable. *** ## Best Practices **Choose appropriate accuracy:** ```typescript theme={null} // Good - Use lowest accuracy needed session.location.subscribeToStream( { accuracy: "hundredMeters" }, // Fine for city-level features handler ); // Avoid - Don't use highest accuracy unless needed session.location.subscribeToStream( { accuracy: "realtime" }, // Drains battery quickly handler ); ``` **Always unsubscribe when done:** ```typescript theme={null} protected async onSession(session: AppSession, sessionId: string, userId: string) { const unsubscribe = session.location.subscribeToStream( { accuracy: "standard" }, handler ); // Important: Clean up to stop location updates session.events.on('disconnect', () => { unsubscribe(); }); } ``` **Handle poll timeouts:** ```typescript theme={null} try { const location = await session.location.getLatestLocation({ accuracy: "high" }); // Use location } catch (error) { // Handle timeout (after 15 seconds) session.logger.error("Location poll timed out"); } ``` **Check accuracy in handler:** ```typescript theme={null} session.location.subscribeToStream( { accuracy: "standard" }, (data) => { if (data.accuracy > 100) { session.logger.warn(`Low accuracy: ${data.accuracy}m`); } // Use location data } ); ``` *** ## Error Handling ### Handling Stream Errors ```typescript theme={null} protected async onSession(session: AppSession, sessionId: string, userId: string) { try { const unsubscribe = session.location.subscribeToStream( { accuracy: "standard" }, (data) => { if (data.accuracy > 100) { session.logger.warn(`Low accuracy: ${data.accuracy}m`); } } ); } catch (error) { session.logger.error("Failed to subscribe to location stream:", error); } } ``` ### Handling Poll Timeouts ```typescript theme={null} try { const location = await session.location.getLatestLocation({ accuracy: "high" }); session.logger.info(`Location: ${location.latitude}, ${location.longitude}`); } catch (error) { session.logger.error("Location request failed:", error); // Provide fallback or notify user } ``` *** ## Next Steps Configure location permissions Complete API reference Display location on dashboard Add voice commands for location (under maintenance, returning later in 2026)