Maps - Overview

 GPS

• A satellite-based navigation system.
• Constellation of satellites orbiting Earth at 20,000 km altitude.
• Each satellite completes an orbit in 11 hours and 58 minutes.
• Satellites continuously send signals to GPS receivers (e.g., mobile devices).
• One-way communication—devices receive signals but do not send data back.
• Devices calculate their position using trilateration, determining the distance to at least three satellites.
• Multiple navigation systems exist; NAVSTAR is used by mobile phones.
• Every point on Earth is covered by at least four satellites.
• Accuracy: Typically 3 - 10 meters.

Latitude/ Longtitude

• Units that represent geographical coordinates.
• (0,0) = Equator & Prime Meridian intersection.
• Geolocation: Process of determining coordinates (latitude/longitude).
• Android provides Location API and Fused Location Provider (combining GPS, Wi-Fi, and sensors for better accuracy).

Google Maps - Camera Attributes

• Google Maps represents a map view as a camera looking down on a flat plane. Key attributes:

  • Target (Location): The center of the map (Lat/Long).
  • Bearing (Orientation): The direction the map points relative to north (measured in degrees, clockwise).
  • Tilt (Viewing Angle):
    • Adjusting tilt gives a perspective view.
    • Nearby objects appear larger, distant ones appear smaller.
  • Zoom:
    • 0 = Entire world width is ~256 dpi.
    • Higher zoom levels show more details.

Adding Google Maps to an Android app

• Uses Google Maps API to display maps similar to the Google Maps app.
• Supports mobile devices, web services, and other platforms.
• Google Maps Plugin: A wrapper around Google Maps API for Flutter, React Native, etc.
• Automatically connects to Google Maps Servers for real-time updates.
• User Interactions: Developers can enable map interaction and add markers.
• Requires Google Play Services in Android Studio for enhanced features.
• Uses Fused Location Provider for better accuracy.
• Requires a Google API Key:
• Register your app on the Google Developer website.
• Add the API Key to the Android Manifest.
• Use class onMapReadyCallBack - inherit

Fragment

• Self-contained UI components within an Activity.
• Can be combined into a single Activity or reused in multiple Activities.
• Have their own lifecycle and can be added/removed dynamically.

Capture Users Location

• Fused Location Provider:
  • Manages location sources (GPS, Wi-Fi, Cell Towers, Sensors).
  • Optimizes battery usage and accuracy based on app needs.
  • class LocationServices can be used
  • part of Google Play Services API
• User Permission Requirements:
  • FINE_LOCATION: Uses GPS (high accuracy, more battery consumption).
  • COARSE_LOCATION: Uses Wi-Fi & Cell Towers (less accurate, lower battery usage).
  • If both permissions are granted, the app selects the best source automatically.