Implement barometric pressure trend monitoring and visualization

6 files changed, 1492 insertions, 0 deletions

diff --git a/android-app/app/src/main/kotlin_old/org/terst/nav/AnchorAlarmManager.kt b/android-app/app/src/main/kotlin_old/org/terst/nav/AnchorAlarmManager.kt
new file mode 100644
index 0000000..d4423db
--- /dev/null
+++ b/android-app/app/src/main/kotlin_old/org/terst/nav/AnchorAlarmManager.kt
@@ -0,0 +1,108 @@
+package org.terst.nav
+
+import android.app.NotificationChannel
+import android.app.NotificationManager
+import android.content.Context
+import android.media.AudioAttributes
+import android.media.RingtoneManager
+import android.net.Uri
+import android.os.Build
+import android.os.VibrationEffect
+import android.os.Vibrator
+import android.os.VibratorManager // For API 31+
+import androidx.core.app.NotificationCompat
+import androidx.core.app.NotificationManagerCompat
+
+class AnchorAlarmManager(private val context: Context) {
+
+    private val CHANNEL_ID = "anchor_alarm_channel"
+    private val NOTIFICATION_ID = 1001
+
+    private var isAlarming: Boolean = false
+    private var ringtone: android.media.Ringtone? = null
+
+    init {
+        createNotificationChannel()
+    }
+
+    private fun createNotificationChannel() {
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+            val name = "Anchor Alarm"
+            val descriptionText = "Notifications for anchor drag events"
+            val importance = NotificationManager.IMPORTANCE_HIGH
+            val channel = NotificationChannel(CHANNEL_ID, name, importance).apply {
+                description = descriptionText
+            }
+            val notificationManager: NotificationManager =
+                context.getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
+            notificationManager.createNotificationChannel(channel)
+        }
+    }
+
+    @Suppress("DEPRECATION")
+    private fun getVibrator(): Vibrator? {
+        return if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.S) {
+            val vibratorManager = context.getSystemService(Context.VIBRATOR_MANAGER_SERVICE) as VibratorManager
+            vibratorManager.defaultVibrator
+        } else {
+            context.getSystemService(Context.VIBRATOR_SERVICE) as Vibrator
+        }
+    }
+
+    fun startAlarm() {
+        if (isAlarming) return
+
+        isAlarming = true
+        // Play sound
+        try {
+            val alarmUri: Uri = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_ALARM)
+            ringtone = RingtoneManager.getRingtone(context, alarmUri)
+            ringtone?.audioAttributes = AudioAttributes.Builder()
+                .setUsage(AudioAttributes.USAGE_ALARM)
+                .setContentType(AudioAttributes.CONTENT_TYPE_SONIFICATION)
+                .build()
+            ringtone?.play()
+        } catch (e: Exception) {
+            e.printStackTrace()
+        }
+
+        // Vibrate
+        val vibrator = getVibrator()
+        if (vibrator?.hasVibrator() == true) {
+            val pattern = longArrayOf(0, 1000, 1000) // Start immediately, vibrate for 1s, pause for 1s
+            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+                vibrator.vibrate(VibrationEffect.createWaveform(pattern, 0)) // Repeat indefinitely
+            } else {
+                vibrator.vibrate(pattern, 0) // Repeat indefinitely
+            }
+        }
+
+        // Show persistent notification
+        showNotification("Anchor Drag Detected!", "Your boat is outside the watch circle.")
+    }
+
+    fun stopAlarm() {
+        if (!isAlarming) return
+
+        isAlarming = false
+        ringtone?.stop()
+        getVibrator()?.cancel()
+        NotificationManagerCompat.from(context).cancel(NOTIFICATION_ID)
+    }
+
+    private fun showNotification(title: String, message: String) {
+        val builder = NotificationCompat.Builder(context, CHANNEL_ID)
+            .setSmallIcon(android.R.drawable.ic_dialog_alert) // Replace with a proper icon
+            .setContentTitle(title)
+            .setContentText(message)
+            .setPriority(NotificationCompat.PRIORITY_HIGH)
+            .setCategory(NotificationCompat.CATEGORY_ALARM)
+            .setOngoing(true) // Makes the notification persistent
+            .setAutoCancel(false) // Does not disappear when tapped
+            .setDefaults(NotificationCompat.DEFAULT_ALL) // Use default sound, vibrate, light (though we manually control sound/vibration)
+
+        with(NotificationManagerCompat.from(context)) {
+            notify(NOTIFICATION_ID, builder.build())
+        }
+    }
+}
diff --git a/android-app/app/src/main/kotlin_old/org/terst/nav/AnchorWatchData.kt b/android-app/app/src/main/kotlin_old/org/terst/nav/AnchorWatchData.kt
new file mode 100644
index 0000000..03e6a2f
--- /dev/null
+++ b/android-app/app/src/main/kotlin_old/org/terst/nav/AnchorWatchData.kt
@@ -0,0 +1,22 @@
+package org.terst.nav
+
+import android.location.Location
+
+data class AnchorWatchState(
+    val anchorLocation: Location? = null,
+    val watchCircleRadiusMeters: Double = DEFAULT_WATCH_CIRCLE_RADIUS_METERS,
+    val setTimeMillis: Long = 0L,
+    val isActive: Boolean = false
+) {
+    companion object {
+        const val DEFAULT_WATCH_CIRCLE_RADIUS_METERS = 50.0 // Default 50 meters
+    }
+
+    fun isDragging(currentLocation: Location): Boolean {
+        anchorLocation ?: return false // Cannot drag if anchor not set
+        if (!isActive) return false // Not active, so not dragging
+
+        val distance = anchorLocation.distanceTo(currentLocation)
+        return distance > watchCircleRadiusMeters
+    }
+}
diff --git a/android-app/app/src/main/kotlin_old/org/terst/nav/LocationService.kt b/android-app/app/src/main/kotlin_old/org/terst/nav/LocationService.kt
new file mode 100644
index 0000000..4b59139
--- /dev/null
+++ b/android-app/app/src/main/kotlin_old/org/terst/nav/LocationService.kt
@@ -0,0 +1,254 @@
+package org.terst.nav
+
+import android.annotation.SuppressLint
+import android.app.Notification
+import android.app.NotificationChannel
+import android.app.NotificationManager
+import android.app.PendingIntent
+import android.app.Service
+import android.content.Context
+import android.content.Intent
+import android.location.Location
+import android.os.IBinder
+import android.os.Looper
+import androidx.core.app.NotificationCompat
+import com.google.android.gms.location.*
+import kotlinx.coroutines.flow.MutableSharedFlow
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.SharedFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.update
+import android.util.Log
+import kotlinx.coroutines.tasks.await
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.SupervisorJob
+import kotlinx.coroutines.cancel
+import kotlinx.coroutines.launch
+
+data class GpsData(
+    val latitude: Double,
+    val longitude: Double,
+    val speedOverGround: Float, // m/s
+    val courseOverGround: Float // degrees
+) {
+    fun toLocation(): Location {
+        val location = Location("GpsData")
+        location.latitude = latitude
+        location.longitude = longitude
+        location.speed = speedOverGround
+        location.bearing = courseOverGround
+        return location
+    }
+}
+
+class LocationService : Service() {
+
+    private lateinit var fusedLocationClient: FusedLocationProviderClient
+    private lateinit var locationCallback: LocationCallback
+    private lateinit var anchorAlarmManager: AnchorAlarmManager
+    private val serviceScope = CoroutineScope(Dispatchers.IO + SupervisorJob())
+
+    private val NOTIFICATION_CHANNEL_ID = "location_service_channel"
+    private val NOTIFICATION_ID = 123
+
+    private var isAlarmTriggered = false // To prevent repeated alarm triggering
+
+    override fun onCreate() {
+        super.onCreate()
+        Log.d("LocationService", "Service created")
+        fusedLocationClient = LocationServices.getFusedLocationProviderClient(this)
+        anchorAlarmManager = AnchorAlarmManager(this) // Initialize with service context
+        createNotificationChannel()
+
+        locationCallback = object : LocationCallback() {
+            override fun onLocationResult(locationResult: LocationResult) {
+                locationResult.lastLocation?.let { location ->
+                    val gpsData = GpsData(
+                        latitude = location.latitude,
+                        longitude = location.longitude,
+                        speedOverGround = location.speed,
+                        courseOverGround = location.bearing
+                    )
+                    serviceScope.launch {
+                        _locationFlow.emit(gpsData) // Emit to shared flow
+                    }
+
+
+                    // Check for anchor drag if anchor watch is active
+                    _anchorWatchState.update { currentState ->
+                        if (currentState.isActive && currentState.anchorLocation != null) {
+                            val isDragging = currentState.isDragging(location)
+                            if (isDragging) {
+                                Log.w("AnchorWatch", "!!! ANCHOR DRAG DETECTED !!! Distance: ${currentState.anchorLocation.distanceTo(location)}m, Radius: ${currentState.watchCircleRadiusMeters}m")
+                                if (!isAlarmTriggered) {
+                                    anchorAlarmManager.startAlarm()
+                                    isAlarmTriggered = true
+                                }
+                            } else {
+                                Log.d("AnchorWatch", "Anchor holding. Distance: ${currentState.anchorLocation.distanceTo(location)}m, Radius: ${currentState.watchCircleRadiusMeters}m")
+                                if (isAlarmTriggered) {
+                                    anchorAlarmManager.stopAlarm()
+                                    isAlarmTriggered = false
+                                }
+                            }
+                        } else {
+                            // If anchor watch is not active, ensure alarm is stopped
+                            if (isAlarmTriggered) {
+                                anchorAlarmManager.stopAlarm()
+                                isAlarmTriggered = false
+                            }
+                        }
+                        currentState
+                    }
+                }
+            }
+        }
+    }
+
+    override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
+        when (intent?.action) {
+            ACTION_START_FOREGROUND_SERVICE -> {
+                Log.d("LocationService", "Starting foreground service")
+                startForeground(NOTIFICATION_ID, createNotification())
+                startLocationUpdatesInternal()
+            }
+            ACTION_STOP_FOREGROUND_SERVICE -> {
+                Log.d("LocationService", "Stopping foreground service")
+                stopLocationUpdatesInternal()
+                stopSelf()
+            }
+            ACTION_START_ANCHOR_WATCH -> {
+                Log.d("LocationService", "Received ACTION_START_ANCHOR_WATCH")
+                val radius = intent.getDoubleExtra(EXTRA_WATCH_RADIUS, AnchorWatchState.DEFAULT_WATCH_CIRCLE_RADIUS_METERS)
+                serviceScope.launch { startAnchorWatch(radius) }
+            }
+            ACTION_STOP_ANCHOR_WATCH -> {
+                Log.d("LocationService", "Received ACTION_STOP_ANCHOR_WATCH")
+                stopAnchorWatch()
+            }
+            ACTION_UPDATE_WATCH_RADIUS -> {
+                Log.d("LocationService", "Received ACTION_UPDATE_WATCH_RADIUS")
+                val radius = intent.getDoubleExtra(EXTRA_WATCH_RADIUS, AnchorWatchState.DEFAULT_WATCH_CIRCLE_RADIUS_METERS)
+                updateWatchCircleRadius(radius)
+            }
+        }
+        return START_NOT_STICKY
+    }
+
+    override fun onBind(intent: Intent?): IBinder? {
+        return null // Not a bound service
+    }
+
+    override fun onDestroy() {
+        super.onDestroy()
+        Log.d("LocationService", "Service destroyed")
+        stopLocationUpdatesInternal()
+        anchorAlarmManager.stopAlarm()
+        _anchorWatchState.value = AnchorWatchState(isActive = false)
+        isAlarmTriggered = false // Reset alarm trigger state
+        serviceScope.cancel() // Cancel the coroutine scope
+    }
+
+    @SuppressLint("MissingPermission")
+    private fun startLocationUpdatesInternal() {
+        Log.d("LocationService", "Requesting location updates")
+        val locationRequest = LocationRequest.Builder(Priority.PRIORITY_HIGH_ACCURACY, 1000)
+            .setMinUpdateIntervalMillis(500)
+            .build()
+        fusedLocationClient.requestLocationUpdates(
+            locationRequest,
+            locationCallback,
+            Looper.getMainLooper()
+        )
+    }
+
+    private fun stopLocationUpdatesInternal() {
+        Log.d("LocationService", "Removing location updates")
+        fusedLocationClient.removeLocationUpdates(locationCallback)
+    }
+
+    private fun createNotificationChannel() {
+        val serviceChannel = NotificationChannel(
+            NOTIFICATION_CHANNEL_ID,
+            "Location Service Channel",
+            NotificationManager.IMPORTANCE_LOW
+        )
+        val manager = getSystemService(NotificationManager::class.java) as NotificationManager
+        manager.createNotificationChannel(serviceChannel)
+    }
+
+    private fun createNotification(): Notification {
+        val notificationIntent = Intent(this, MainActivity::class.java)
+        val pendingIntent = PendingIntent.getActivity(
+            this,
+            0,
+            notificationIntent,
+            PendingIntent.FLAG_IMMUTABLE
+        )
+
+        return NotificationCompat.Builder(this, NOTIFICATION_CHANNEL_ID)
+            .setContentTitle("Sailing Companion")
+            .setContentText("Tracking your location in the background...")
+            .setSmallIcon(R.drawable.ic_anchor)
+            .setContentIntent(pendingIntent)
+            .build()
+    }
+
+    /**
+     * Starts the anchor watch with the current location as the anchor point.
+     * @param radiusMeters The watch circle radius in meters.
+     */
+    @SuppressLint("MissingPermission")
+    suspend fun startAnchorWatch(radiusMeters: Double = AnchorWatchState.DEFAULT_WATCH_CIRCLE_RADIUS_METERS) {
+        val lastLocation = fusedLocationClient.lastLocation.await()
+        lastLocation?.let { location ->
+            _anchorWatchState.update { AnchorWatchState(
+                anchorLocation = location,
+                watchCircleRadiusMeters = radiusMeters,
+                setTimeMillis = System.currentTimeMillis(),
+                isActive = true
+            ) }
+            Log.i("AnchorWatch", "Anchor watch started at lat: ${location.latitude}, lon: ${location.longitude} with radius: ${radiusMeters}m")
+        } ?: run {
+            Log.e("AnchorWatch", "Could not start anchor watch: Last known location is null.")
+            // Handle error, e.g., show a toast to the user
+        }
+    }
+
+    /**
+     * Stops the anchor watch.
+     */
+    fun stopAnchorWatch() {
+        _anchorWatchState.update { AnchorWatchState(isActive = false) }
+        Log.i("AnchorWatch", "Anchor watch stopped.")
+        anchorAlarmManager.stopAlarm()
+        isAlarmTriggered = false
+    }
+
+    /**
+     * Updates the watch circle radius.
+     */
+    fun updateWatchCircleRadius(radiusMeters: Double) {
+        _anchorWatchState.update { it.copy(watchCircleRadiusMeters = radiusMeters) }
+        Log.d("AnchorWatch", "Watch circle radius updated to ${radiusMeters}m.")
+    }
+
+    companion object {
+        const val ACTION_START_FOREGROUND_SERVICE = "ACTION_START_FOREGROUND_SERVICE"
+        const val ACTION_STOP_FOREGROUND_SERVICE = "ACTION_STOP_FOREGROUND_SERVICE"
+        const val ACTION_START_ANCHOR_WATCH = "ACTION_START_ANCHOR_WATCH"
+        const val ACTION_STOP_ANCHOR_WATCH = "ACTION_STOP_ANCHOR_WATCH"
+        const val ACTION_UPDATE_WATCH_RADIUS = "ACTION_UPDATE_WATCH_RADIUS"
+        const val EXTRA_WATCH_RADIUS = "extra_watch_radius"
+
+        // Publicly accessible flows
+        val locationFlow: SharedFlow<GpsData>
+            get() = _locationFlow
+        val anchorWatchState: StateFlow<AnchorWatchState>
+            get() = _anchorWatchState
+
+        private val _locationFlow = MutableSharedFlow<GpsData>(replay = 1)
+        private val _anchorWatchState = MutableStateFlow(AnchorWatchState())
+    }
+}
diff --git a/android-app/app/src/main/kotlin_old/org/terst/nav/MainActivity.kt b/android-app/app/src/main/kotlin_old/org/terst/nav/MainActivity.kt
new file mode 100644
index 0000000..a32fb18
--- /dev/null
+++ b/android-app/app/src/main/kotlin_old/org/terst/nav/MainActivity.kt
@@ -0,0 +1,670 @@
+package org.terst.nav
+
+import android.Manifest
+import android.content.pm.PackageManager
+import android.graphics.BitmapFactory
+import android.location.Location
+import android.media.MediaPlayer
+import android.os.Build
+import android.os.Bundle
+import android.content.Intent
+import android.util.Log
+import android.view.View
+import android.widget.Button
+import android.widget.LinearLayout
+import android.widget.TextView
+import android.widget.Toast
+import androidx.activity.result.contract.ActivityResultContracts
+import androidx.appcompat.app.AppCompatActivity
+import androidx.constraintlayout.widget.ConstraintLayout
+import androidx.core.content.ContextCompat
+import androidx.lifecycle.lifecycleScope
+import com.google.android.material.floatingactionbutton.FloatingActionButton
+import org.maplibre.android.MapLibre
+import org.maplibre.android.maps.MapView
+import org.maplibre.android.maps.MapLibreMap
+import org.maplibre.android.maps.Style
+import org.maplibre.android.style.layers.CircleLayer
+import org.maplibre.android.style.layers.PropertyFactory
+import org.maplibre.android.style.layers.SymbolLayer
+import org.maplibre.android.style.sources.GeoJsonSource
+import org.maplibre.geojson.Feature
+import org.maplibre.geojson.FeatureCollection
+import org.maplibre.geojson.Point
+import org.maplibre.geojson.Polygon
+import org.maplibre.geojson.LineString
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.flow.distinctUntilChanged
+import kotlinx.coroutines.flow.filterNotNull
+import kotlinx.coroutines.flow.firstOrNull
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.withContext
+import java.util.Locale
+import java.util.concurrent.TimeUnit
+import kotlin.math.cos
+import kotlin.math.sin
+import kotlin.math.sqrt
+import kotlin.math.atan2
+
+data class MobWaypoint(
+    val latitude: Double,
+    val longitude: Double,
+    val timestamp: Long // System.currentTimeMillis()
+)
+
+class MainActivity : AppCompatActivity() {
+
+    private var mapView: MapView? = null
+    private lateinit var instrumentDisplayContainer: ConstraintLayout
+    private lateinit var fabToggleInstruments: FloatingActionButton
+    private lateinit var fabMob: FloatingActionButton
+
+    // MapLibreMap instance
+    private var maplibreMap: MapLibreMap? = null
+
+    // MapLibre Layers and Sources for Anchor Watch
+    private val ANCHOR_POINT_SOURCE_ID = "anchor-point-source"
+    private val ANCHOR_CIRCLE_SOURCE_ID = "anchor-circle-source"
+    private val ANCHOR_POINT_LAYER_ID = "anchor-point-layer"
+    private val ANCHOR_CIRCLE_LAYER_ID = "anchor-circle-layer"
+    private val ANCHOR_ICON_ID = "anchor-icon"
+
+    private var anchorPointSource: GeoJsonSource? = null
+    private var anchorCircleSource: GeoJsonSource? = null
+
+    // MOB UI elements
+    private lateinit var mobNavigationContainer: ConstraintLayout
+    private lateinit var mobValueDistance: TextView
+    private lateinit var mobValueElapsedTime: TextView
+    private lateinit var mobRecoveredButton: Button
+
+    // MOB State
+    private var mobActivated: Boolean = false
+    private var activeMobWaypoint: MobWaypoint? = null
+
+    // Media player for MOB alarm
+    private var mobMediaPlayer: MediaPlayer? = null
+
+    // Instrument TextViews
+    private lateinit var valueAws: TextView
+    private lateinit var valueTws: TextView
+    private lateinit var valueHdg: TextView
+    private lateinit var valueCog: TextView
+    private lateinit var valueBsp: TextView
+    private lateinit var valueSog: TextView
+    private lateinit var valueVmg: TextView
+    private lateinit var valueDepth: TextView
+    private lateinit var valuePolarPct: TextView
+    private lateinit var polarDiagramView: PolarDiagramView // Reference to the custom view
+
+    // Anchor Watch UI elements
+    private lateinit var fabAnchor: FloatingActionButton
+    private lateinit var anchorConfigContainer: ConstraintLayout
+    private lateinit var anchorStatusText: TextView
+    private lateinit var anchorRadiusText: TextView
+    private lateinit var buttonDecreaseRadius: Button
+    private lateinit var buttonIncreaseRadius: Button
+    private lateinit var buttonSetAnchor: Button
+    private lateinit var buttonStopAnchor: Button
+
+    private var currentWatchCircleRadius = AnchorWatchState.DEFAULT_WATCH_CIRCLE_RADIUS_METERS
+
+    // Register the permissions callback, which handles the user's response to the
+    // system permissions dialog.
+    private val requestPermissionLauncher =
+        registerForActivityResult(ActivityResultContracts.RequestMultiplePermissions()) { permissions ->
+            val fineLocationGranted = permissions[Manifest.permission.ACCESS_FINE_LOCATION] == true
+            val coarseLocationGranted = permissions[Manifest.permission.ACCESS_COARSE_LOCATION] == true
+            val backgroundLocationGranted = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
+                permissions[Manifest.permission.ACCESS_BACKGROUND_LOCATION] == true
+            } else true // Not needed below Android 10
+
+            if (fineLocationGranted && coarseLocationGranted && backgroundLocationGranted) {
+                // Permissions granted, start location service and observe updates
+                Toast.makeText(this, "Location permissions granted", Toast.LENGTH_SHORT).show()
+                startLocationService()
+                observeLocationUpdates() // Start observing location updates
+                observeAnchorWatchState() // Start observing anchor watch state
+            } else {
+                // Permissions denied, handle the case (e.g., show a message to the user)
+                Toast.makeText(this, "Location permissions denied", Toast.LENGTH_LONG).show()
+                Log.e("MainActivity", "Location permissions denied by user.")
+            }
+        }
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        // MapLibre access token only needed for Mapbox styles, but good practice to initialize
+        MapLibre.getInstance(this)
+        setContentView(R.layout.activity_main)
+
+        val permissionsToRequest = mutableListOf(
+            Manifest.permission.ACCESS_FINE_LOCATION,
+            Manifest.permission.ACCESS_COARSE_LOCATION
+        )
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
+            permissionsToRequest.add(Manifest.permission.ACCESS_BACKGROUND_LOCATION)
+        }
+
+        // Check and request location permissions
+        val allPermissionsGranted = permissionsToRequest.all {
+            ContextCompat.checkSelfPermission(this, it) == PackageManager.PERMISSION_GRANTED
+        }
+
+        if (!allPermissionsGranted) {
+            requestPermissionLauncher.launch(permissionsToRequest.toTypedArray())
+        } else {
+            // Permissions already granted, start location service
+            startLocationService()
+            observeLocationUpdates() // Start observing location updates
+            observeAnchorWatchState() // Start observing anchor watch state
+        }
+
+        mapView = findViewById<MapView>(R.id.mapView)
+        mapView?.onCreate(savedInstanceState)
+        mapView?.getMapAsync { maplibreMap ->
+            this.maplibreMap = maplibreMap // Assign to class member
+            maplibreMap.setStyle(Style.Builder().fromUri("https://tiles.openseamap.org/seamark/osm-bright/style.json")) { style ->
+                setupAnchorMapLayers(style)
+            }
+        }
+
+        instrumentDisplayContainer = findViewById(R.id.instrument_display_container)
+        fabToggleInstruments = findViewById(R.id.fab_toggle_instruments)
+        fabMob = findViewById(R.id.fab_mob)
+
+        // Initialize MOB UI elements
+        mobNavigationContainer = findViewById(R.id.mob_navigation_container)
+        mobValueDistance = findViewById(R.id.mob_value_distance)
+        mobValueElapsedTime = findViewById(R.id.mob_value_elapsed_time)
+        mobRecoveredButton = findViewById(R.id.mob_recovered_button)
+
+        // Initialize instrument TextViews
+        valueAws = findViewById(R.id.value_aws)
+        valueTws = findViewById(R.id.value_tws)
+        valueHdg = findViewById(R.id.value_hdg)
+        valueCog = findViewById(R.id.value_cog)
+        valueBsp = findViewById(R.id.value_bsp)
+        valueSog = findViewById(R.id.value_sog)
+        valueVmg = findViewById(R.id.value_vmg)
+        valueDepth = findViewById(R.id.value_depth)
+        valuePolarPct = findViewById(R.id.value_polar_pct)
+
+        // Initialize PolarDiagramView
+        polarDiagramView = findViewById(R.id.polar_diagram_view)
+
+        // Set up mock polar data
+        val mockPolarTable = createMockPolarTable()
+        polarDiagramView.setPolarTable(mockPolarTable)
+
+        // Simulate real-time updates for the polar diagram
+        lifecycleScope.launch {
+            var simulatedTws = 8.0
+            var simulatedTwa = 40.0
+            var simulatedBsp = mockPolarTable.interpolateBsp(simulatedTws, simulatedTwa)
+
+            while (true) {
+                // Update instrument display with current simulated values
+                updateInstrumentDisplay(
+                    aws = "%.1f".format(Locale.getDefault(), simulatedTws * 1.1), // AWS usually higher than TWS
+                    tws = "%.1f".format(Locale.getDefault(), simulatedTws),
+                    hdg = "---", // No mock for HDG
+                    cog = "---", // No mock for COG
+                    bsp = "%.1f".format(Locale.getDefault(), simulatedBsp),
+                    sog = "%.1f".format(Locale.getDefault(), simulatedBsp * 0.95), // SOG usually slightly less than BSP
+                    vmg = "%.1f".format(Locale.getDefault(), mockPolarTable.curves.firstOrNull { it.twS == simulatedTws }?.calculateVmg(simulatedTwa, simulatedBsp) ?: 0.0),
+                    depth = getString(R.string.placeholder_depth_value),
+                    polarPct = "%.0f%%".format(Locale.getDefault(), mockPolarTable.calculatePolarPercentage(simulatedTws, simulatedTwa, simulatedBsp))
+                )
+                polarDiagramView.setCurrentPerformance(simulatedTws, simulatedTwa, simulatedBsp)
+
+                // Slowly change TWA to simulate sailing
+                simulatedTwa += 0.5 // Change by 0.5 degrees
+                if (simulatedTwa > 170) simulatedTwa = 40.0 // Reset or change direction
+                simulatedBsp = mockPolarTable.interpolateBsp(simulatedTws, simulatedTwa)
+
+                kotlinx.coroutines.delay(1000) // Update every second
+            }
+        }
+
+        // Initialize Anchor Watch UI elements
+        fabAnchor = findViewById(R.id.fab_anchor)
+        anchorConfigContainer = findViewById(R.id.anchor_config_container)
+        anchorStatusText = findViewById(R.id.anchor_status_text)
+        anchorRadiusText = findViewById(R.id.anchor_radius_text)
+        buttonDecreaseRadius = findViewById(R.id.button_decrease_radius)
+        buttonIncreaseRadius = findViewById(R.id.button_increase_radius)
+        buttonSetAnchor = findViewById(R.id.button_set_anchor)
+        buttonStopAnchor = findViewById(R.id.button_stop_anchor)
+
+        // Set initial placeholder values
+        updateInstrumentDisplay(
+            aws = getString(R.string.placeholder_aws_value),
+            tws = getString(R.string.placeholder_tws_value),
+            hdg = getString(R.string.placeholder_hdg_value),
+            cog = getString(R.string.placeholder_cog_value),
+            bsp = getString(R.string.placeholder_bsp_value),
+            sog = getString(R.string.placeholder_sog_value),
+            vmg = getString(R.string.placeholder_vmg_value),
+            depth = getString(R.string.placeholder_depth_value),
+            polarPct = getString(R.string.placeholder_polar_value)
+        )
+
+        fabToggleInstruments.setOnClickListener {
+            if (instrumentDisplayContainer.visibility == View.VISIBLE) {
+                instrumentDisplayContainer.visibility = View.GONE
+                mapView?.visibility = View.VISIBLE
+            } else {
+                instrumentDisplayContainer.visibility = View.VISIBLE
+                mapView?.visibility = View.GONE
+            }
+        }
+
+        fabMob.setOnClickListener {
+            activateMob()
+        }
+
+        fabAnchor.setOnClickListener {
+            if (anchorConfigContainer.visibility == View.VISIBLE) {
+                anchorConfigContainer.visibility = View.GONE
+            } else {
+                anchorConfigContainer.visibility = View.VISIBLE
+                // Ensure anchor radius display is updated when shown
+                anchorRadiusText.text = String.format(Locale.getDefault(), "Radius: %.1fm", currentWatchCircleRadius)
+            }
+        }
+
+        buttonDecreaseRadius.setOnClickListener {
+            currentWatchCircleRadius = (currentWatchCircleRadius - 5).coerceAtLeast(10.0) // Minimum 10m
+            anchorRadiusText.text = String.format(Locale.getDefault(), "Radius: %.1fm", currentWatchCircleRadius)
+            val intent = Intent(this, LocationService::class.java).apply {
+                action = LocationService.ACTION_UPDATE_WATCH_RADIUS
+                putExtra(LocationService.EXTRA_WATCH_RADIUS, currentWatchCircleRadius)
+            }
+            startService(intent)
+        }
+
+        buttonIncreaseRadius.setOnClickListener {
+            currentWatchCircleRadius = (currentWatchCircleRadius + 5).coerceAtMost(200.0) // Maximum 200m
+            anchorRadiusText.text = String.format(Locale.getDefault(), "Radius: %.1fm", currentWatchCircleRadius)
+            val intent = Intent(this, LocationService::class.java).apply {
+                action = LocationService.ACTION_UPDATE_WATCH_RADIUS
+                putExtra(LocationService.EXTRA_WATCH_RADIUS, currentWatchCircleRadius)
+            }
+            startService(intent)
+        }
+
+        buttonSetAnchor.setOnClickListener {
+            val intent = Intent(this, LocationService::class.java).apply {
+                action = LocationService.ACTION_START_ANCHOR_WATCH
+                putExtra(LocationService.EXTRA_WATCH_RADIUS, currentWatchCircleRadius)
+            }
+            startService(intent)
+            Toast.makeText(this@MainActivity, "Anchor watch set!", Toast.LENGTH_SHORT).show()
+        }
+
+        buttonStopAnchor.setOnClickListener {
+            val intent = Intent(this, LocationService::class.java).apply {
+                action = LocationService.ACTION_STOP_ANCHOR_WATCH
+            }
+            startService(intent)
+            Toast.makeText(this@MainActivity, "Anchor watch stopped.", Toast.LENGTH_SHORT).show()
+        }
+
+        mobRecoveredButton.setOnClickListener {
+            recoverMob()
+        }
+    }
+
+    private fun startLocationService() {
+        val intent = Intent(this, LocationService::class.java).apply {
+            action = LocationService.ACTION_START_FOREGROUND_SERVICE
+        }
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+            startForegroundService(intent)
+        } else {
+            startService(intent)
+        }
+    }
+
+    private fun stopLocationService() {
+        val intent = Intent(this, LocationService::class.java).apply {
+            action = LocationService.ACTION_STOP_FOREGROUND_SERVICE
+        }
+        stopService(intent)
+    }
+
+    private fun createMockPolarTable(): PolarTable {
+        // Example polar data for a hypothetical boat
+        // TWS 6 knots
+        val polar6k = PolarCurve(
+            twS = 6.0,
+            points = listOf(
+                PolarPoint(tWa = 30.0, bSp = 3.0),
+                PolarPoint(tWa = 45.0, bSp = 4.0),
+                PolarPoint(tWa = 60.0, bSp = 4.5),
+                PolarPoint(tWa = 90.0, bSp = 4.8),
+                PolarPoint(tWa = 120.0, bSp = 4.0),
+                PolarPoint(tWa = 150.0, bSp = 3.0),
+                PolarPoint(tWa = 180.0, bSp = 2.0)
+            )
+        )
+
+        // TWS 8 knots
+        val polar8k = PolarCurve(
+            twS = 8.0,
+            points = listOf(
+                PolarPoint(tWa = 30.0, bSp = 4.0),
+                PolarPoint(tWa = 45.0, bSp = 5.0),
+                PolarPoint(tWa = 60.0, bSp = 5.5),
+                PolarPoint(tWa = 90.0, bSp = 5.8),
+                PolarPoint(tWa = 120.0, bSp = 5.0),
+                PolarPoint(tWa = 150.0, bSp = 4.0),
+                PolarPoint(tWa = 180.0, bSp = 2.5)
+            )
+        )
+
+        // TWS 10 knots
+        val polar10k = PolarCurve(
+            twS = 10.0,
+            points = listOf(
+                PolarPoint(tWa = 30.0, bSp = 5.0),
+                PolarPoint(tWa = 45.0, bSp = 6.0),
+                PolarPoint(tWa = 60.0, bSp = 6.5),
+                PolarPoint(tWa = 90.0, bSp = 6.8),
+                PolarPoint(tWa = 120.0, bSp = 6.0),
+                PolarPoint(tWa = 150.0, bSp = 4.5),
+                PolarPoint(tWa = 180.0, bSp = 3.0)
+            )
+        )
+
+        return PolarTable(curves = listOf(polar6k, polar8k, polar10k))
+    }
+
+
+    private fun setupAnchorMapLayers(style: Style) {
+        // Add anchor icon
+        style.addImage(ANCHOR_ICON_ID, BitmapFactory.decodeResource(resources, R.drawable.ic_anchor))
+
+        // Create sources
+        anchorPointSource = GeoJsonSource(ANCHOR_POINT_SOURCE_ID)
+        anchorPointSource?.setGeoJson(FeatureCollection.fromFeatures(emptyList<Feature>()))
+        
+        anchorCircleSource = GeoJsonSource(ANCHOR_CIRCLE_SOURCE_ID)
+        anchorCircleSource?.setGeoJson(FeatureCollection.fromFeatures(emptyList<Feature>()))
+        
+        style.addSource(anchorPointSource!!)
+        style.addSource(anchorCircleSource!!)
+
+        // Create layers
+        val anchorPointLayer = SymbolLayer(ANCHOR_POINT_LAYER_ID, ANCHOR_POINT_SOURCE_ID).apply {
+            setProperties(
+                PropertyFactory.iconImage(ANCHOR_ICON_ID),
+                PropertyFactory.iconAllowOverlap(true),
+                PropertyFactory.iconIgnorePlacement(true)
+            )
+        }
+        val anchorCircleLayer = CircleLayer(ANCHOR_CIRCLE_LAYER_ID, ANCHOR_CIRCLE_SOURCE_ID).apply {
+            setProperties(
+                PropertyFactory.circleColor(ContextCompat.getColor(this@MainActivity, R.color.anchor_button_background)),
+                PropertyFactory.circleOpacity(0.3f),
+                PropertyFactory.circleStrokeWidth(2.0f),
+                PropertyFactory.circleStrokeColor(ContextCompat.getColor(this@MainActivity, R.color.anchor_button_background))
+            )
+        }
+
+        style.addLayer(anchorCircleLayer)
+        style.addLayer(anchorPointLayer)
+    }
+
+    private fun updateAnchorMapLayers(state: AnchorWatchState) {
+        maplibreMap?.getStyle { style ->
+            if (state.isActive && state.anchorLocation != null) {
+                // Update anchor point
+                val anchorPoint = Point.fromLngLat(state.anchorLocation.longitude, state.anchorLocation.latitude)
+                anchorPointSource?.setGeoJson(Feature.fromGeometry(anchorPoint))
+
+                // Update watch circle
+                val watchCirclePolygon = createWatchCirclePolygon(anchorPoint, state.watchCircleRadiusMeters)
+                anchorCircleSource?.setGeoJson(Feature.fromGeometry(watchCirclePolygon))
+
+                // Set layer visibility to visible
+                style.getLayer(ANCHOR_POINT_LAYER_ID)?.setProperties(PropertyFactory.visibility(org.maplibre.android.style.layers.Property.VISIBLE))
+                style.getLayer(ANCHOR_CIRCLE_LAYER_ID)?.setProperties(PropertyFactory.visibility(org.maplibre.android.style.layers.Property.VISIBLE))
+            } else {
+                // Clear sources and hide layers
+                anchorPointSource?.setGeoJson(FeatureCollection.fromFeatures(emptyList<Feature>()))
+                anchorCircleSource?.setGeoJson(FeatureCollection.fromFeatures(emptyList<Feature>()))
+                style.getLayer(ANCHOR_POINT_LAYER_ID)?.setProperties(PropertyFactory.visibility(org.maplibre.android.style.layers.Property.NONE))
+                style.getLayer(ANCHOR_CIRCLE_LAYER_ID)?.setProperties(PropertyFactory.visibility(org.maplibre.android.style.layers.Property.NONE))
+            }
+        }
+    }
+
+    // Helper function to create a GeoJSON Polygon for a circle
+    private fun createWatchCirclePolygon(center: Point, radiusMeters: Double, steps: Int = 64): Polygon {
+        val coordinates = mutableListOf<Point>()
+        val earthRadius = 6371000.0 // Earth's radius in meters
+
+        for (i in 0..steps) {
+            val angle = 2 * Math.PI * i / steps
+            val lat = center.latitude() + (radiusMeters / earthRadius) * (180 / Math.PI) * Math.cos(angle)
+            val lon = center.longitude() + (radiusMeters / earthRadius) * (180 / Math.PI) * Math.sin(angle) / Math.cos(Math.toRadians(center.latitude()))
+            coordinates.add(Point.fromLngLat(lon, lat))
+        }
+        return Polygon.fromLngLats(listOf(coordinates))
+    }
+
+    private fun observeLocationUpdates() {
+        lifecycleScope.launch {
+            // Observe from the static locationFlow in LocationService
+            LocationService.locationFlow.distinctUntilChanged().collect { gpsData ->
+                if (mobActivated && activeMobWaypoint != null) {
+                    val mobLocation = Location("").apply {
+                        latitude = activeMobWaypoint!!.latitude
+                        longitude = activeMobWaypoint!!.longitude
+                    }
+                    val currentPosition = Location("").apply {
+                        latitude = gpsData.latitude
+                        longitude = gpsData.longitude
+                    }
+
+                    val distance = currentPosition.distanceTo(mobLocation) // distance in meters
+                    val elapsedTime = System.currentTimeMillis() - activeMobWaypoint!!.timestamp
+
+                    withContext(Dispatchers.Main) {
+                        mobValueDistance.text = String.format(Locale.getDefault(), "%.1f m", distance)
+                        mobValueElapsedTime.text = formatElapsedTime(elapsedTime)
+                        // TODO: Update bearing arrow (requires custom view or rotation logic)
+                    }
+                }
+            }
+        }
+    }
+
+    private fun observeAnchorWatchState() {
+        lifecycleScope.launch {
+            // Observe from the static anchorWatchState in LocationService
+            LocationService.anchorWatchState.collect { state ->
+                withContext(Dispatchers.Main) {
+                    updateAnchorMapLayers(state) // Update map layers
+                    if (state.isActive && state.anchorLocation != null) {
+                        currentWatchCircleRadius = state.watchCircleRadiusMeters
+                        anchorRadiusText.text = String.format(Locale.getDefault(), "Radius: %.1fm", currentWatchCircleRadius)
+
+                        // Get the current location from the static flow
+                        val currentLocation = LocationService.locationFlow.firstOrNull()?.toLocation()
+                        if (currentLocation != null) {
+                            val distance = state.anchorLocation.distanceTo(currentLocation)
+                            val distanceDiff = distance - state.watchCircleRadiusMeters
+                            if (distanceDiff > 0) {
+                                anchorStatusText.text = String.format(
+                                    Locale.getDefault(),
+                                    getString(R.string.anchor_active_dragging_format),
+                                    state.anchorLocation.latitude,
+                                    state.anchorLocation.longitude,
+                                    state.watchCircleRadiusMeters,
+                                    distance,
+                                    distanceDiff
+                                )
+                                anchorStatusText.setTextColor(ContextCompat.getColor(this@MainActivity, R.color.instrument_text_alarm))
+                            } else {
+                                anchorStatusText.text = String.format(
+                                    Locale.getDefault(),
+                                    getString(R.string.anchor_active_format),
+                                    state.anchorLocation.latitude,
+                                    state.anchorLocation.longitude,
+                                    state.watchCircleRadiusMeters,
+                                    distance,
+                                    -distanceDiff // distance FROM limit
+                                )
+                                anchorStatusText.setTextColor(ContextCompat.getColor(this@MainActivity, R.color.instrument_text_normal))
+                            }
+                        } else {
+                            anchorStatusText.text = "Anchor watch active (waiting for location...)"
+                            anchorStatusText.setTextColor(ContextCompat.getColor(this@MainActivity, R.color.instrument_text_normal))
+                        }
+                    } else {
+                        anchorStatusText.text = getString(R.string.anchor_inactive)
+                        anchorStatusText.setTextColor(ContextCompat.getColor(this@MainActivity, R.color.instrument_text_normal))
+                    }
+                }
+            }
+        }
+    }
+
+    private fun activateMob() {
+        // Get last known location from the static flow
+        lifecycleScope.launch {
+            val lastGpsData: GpsData? = LocationService.locationFlow.firstOrNull()
+            if (lastGpsData != null) {
+                activeMobWaypoint = MobWaypoint(
+                    latitude = lastGpsData.latitude,
+                    longitude = lastGpsData.longitude,
+                    timestamp = System.currentTimeMillis()
+                )
+                mobActivated = true
+                Log.d("MainActivity", "MOB Activated! Location: ${activeMobWaypoint!!.latitude}, ${activeMobWaypoint!!.longitude} at ${activeMobWaypoint!!.timestamp}")
+                Toast.makeText(this@MainActivity, "MOB Activated!", Toast.LENGTH_SHORT).show()
+
+                // Switch display to MOB navigation view
+                mapView?.visibility = View.GONE
+                instrumentDisplayContainer.visibility = View.GONE
+                fabToggleInstruments.visibility = View.GONE
+                fabMob.visibility = View.GONE
+                anchorConfigContainer.visibility = View.GONE // Hide anchor config
+                fabAnchor.visibility = View.GONE // Hide anchor FAB
+                mobNavigationContainer.visibility = View.VISIBLE
+
+
+                // Sound continuous alarm
+                mobMediaPlayer = MediaPlayer.create(this@MainActivity, R.raw.mob_alarm).apply {
+                    isLooping = true
+                    start()
+                }
+
+                // Log event to logbook
+                logMobEvent(activeMobWaypoint!!)
+            } else {
+                Toast.makeText(this@MainActivity, "Could not get current location for MOB", Toast.LENGTH_SHORT).show()
+                Log.e("MainActivity", "Last known location is null, cannot activate MOB.")
+            }
+        }
+    }
+
+    private fun recoverMob() {
+        mobActivated = false
+        activeMobWaypoint = null
+        stopMobAlarm()
+
+        mobNavigationContainer.visibility = View.GONE
+        mapView?.visibility = View.VISIBLE
+        // instrumentDisplayContainer visibility is controlled by fabToggleInstruments, so leave as is
+        fabToggleInstruments.visibility = View.VISIBLE
+        fabMob.visibility = View.VISIBLE
+        fabAnchor.visibility = View.VISIBLE // Show anchor FAB
+        anchorConfigContainer.visibility = View.GONE // Hide anchor config
+
+        Toast.makeText(this, "MOB Recovery initiated.", Toast.LENGTH_SHORT).show()
+        Log.d("MainActivity", "MOB Recovery initiated.")
+    }
+
+    private fun stopMobAlarm() {
+        mobMediaPlayer?.stop()
+        mobMediaPlayer?.release()
+        mobMediaPlayer = null
+        Log.d("MainActivity", "MOB Alarm stopped and released.")
+    }
+
+    private fun logMobEvent(mobWaypoint: MobWaypoint) {
+        Log.i("Logbook", "MOB Event: Lat ${mobWaypoint.latitude}, Lon ${mobWaypoint.longitude}, Time ${mobWaypoint.timestamp}")
+        // TODO: Integrate with actual logbook system for persistence
+    }
+
+
+    private fun formatElapsedTime(milliseconds: Long): String {
+        val hours = TimeUnit.MILLISECONDS.toHours(milliseconds)
+        val minutes = TimeUnit.MILLISECONDS.toMinutes(milliseconds) % 60
+        val seconds = TimeUnit.MILLISECONDS.toSeconds(milliseconds) % 60
+        return String.format(Locale.getDefault(), "%02d:%02d:%02d", hours, minutes, seconds)
+    }
+
+    private fun updateInstrumentDisplay(
+        aws: String,
+        tws: String,
+        hdg: String,
+        cog: String,
+        bsp: String,
+        sog: String,
+        vmg: String,
+        depth: String,
+        polarPct: String
+    ) {
+        valueAws.text = aws
+        valueTws.text = tws
+        valueHdg.text = hdg
+        valueCog.text = cog
+        valueBsp.text = bsp
+        valueSog.text = sog
+        valueVmg.text = vmg
+        valueDepth.text = depth
+        valuePolarPct.text = polarPct
+    }
+
+    override fun onStart() {
+        super.onStart()
+        mapView?.onStart()
+    }
+
+    override fun onResume() {
+        super.onResume()
+        mapView?.onResume()
+    }
+
+    override fun onPause() {
+        super.onPause()
+        mapView?.onPause()
+    }
+
+    override fun onStop() {
+        super.onStop()
+        mapView?.onStop()
+    }
+
+    override fun onSaveInstanceState(outState: Bundle) {
+        super.onSaveInstanceState(outState)
+        mapView?.onSaveInstanceState(outState)
+    }
+
+    override fun onLowMemory() {
+        super.onLowMemory()
+        mapView?.onLowMemory()
+    }
+
+    override fun onDestroy() {
+        super.onDestroy()
+        mapView?.onDestroy()
+        mobMediaPlayer?.release() // Ensure media player is released on destroy
+    }
+}
diff --git a/android-app/app/src/main/kotlin_old/org/terst/nav/PolarData.kt b/android-app/app/src/main/kotlin_old/org/terst/nav/PolarData.kt
new file mode 100644
index 0000000..88a8d0d
--- /dev/null
+++ b/android-app/app/src/main/kotlin_old/org/terst/nav/PolarData.kt
@@ -0,0 +1,168 @@
+package org.terst.nav
+
+import kotlin.math.abs
+import kotlin.math.cos
+import kotlin.math.max
+import kotlin.math.min
+
+// Represents a single point on a polar curve: True Wind Angle and target Boat Speed
+data class PolarPoint(val tWa: Double, val bSp: Double)
+
+// Represents a polar curve for a specific True Wind Speed
+data class PolarCurve(val twS: Double, val points: List<PolarPoint>) {
+    init {
+        require(points.isNotEmpty()) { "PolarCurve must have at least one point." }
+        require(points.all { it.tWa in 0.0..180.0 }) {
+            "TWA in PolarCurve must be between 0 and 180 degrees."
+        }
+        require(points.zipWithNext().all { it.first.tWa < it.second.tWa }) {
+            "PolarPoints in a PolarCurve must be sorted by TWA."
+        }
+    }
+
+    /**
+     * Interpolates the target boat speed for a given True Wind Angle (TWA)
+     * within this specific polar curve (constant TWS).
+     */
+    fun interpolateBsp(twa: Double): Double {
+        val absoluteTwa = abs(twa)
+        if (absoluteTwa < points.first().tWa) return points.first().bSp
+        if (absoluteTwa > points.last().tWa) return points.last().bSp
+
+        for (i in 0 until points.size - 1) {
+            val p1 = points[i]
+            val p2 = points[i + 1]
+            if (absoluteTwa >= p1.tWa && absoluteTwa <= p2.tWa) {
+                val ratio = (absoluteTwa - p1.tWa) / (p2.tWa - p1.tWa)
+                return p1.bSp + ratio * (p2.bSp - p1.bSp)
+            }
+        }
+        return 0.0
+    }
+
+    /**
+     * Calculates the Velocity Made Good (VMG) for a given TWA and BSP.
+     * VMG = BSP * cos(TWA)
+     */
+    fun calculateVmg(twa: Double, bsp: Double): Double {
+        return bsp * cos(Math.toRadians(twa))
+    }
+
+    /**
+     * Finds the TWA that yields the maximum upwind VMG for this polar curve.
+     */
+    fun findOptimalUpwindTwa(): Double {
+        var maxVmg = -Double.MAX_VALUE
+        var optimalTwa = 0.0
+        // Search through TWA 0 to 90
+        for (twa in 0..90) {
+            val bsp = interpolateBsp(twa.toDouble())
+            val vmg = calculateVmg(twa.toDouble(), bsp)
+            if (vmg > maxVmg) {
+                maxVmg = vmg
+                optimalTwa = twa.toDouble()
+            }
+        }
+        return optimalTwa
+    }
+
+    /**
+     * Finds the TWA that yields the maximum downwind VMG for this polar curve.
+     */
+    fun findOptimalDownwindTwa(): Double {
+        var maxVmg = -Double.MAX_VALUE // We want the most negative VMG for downwind
+        var optimalTwa = 180.0
+        // Search through TWA 90 to 180
+        // For downwind, VMG is negative (moving away from wind)
+        // We look for the minimum value (largest absolute negative)
+        for (twa in 90..180) {
+            val bsp = interpolateBsp(twa.toDouble())
+            val vmg = calculateVmg(twa.toDouble(), bsp)
+            if (vmg < maxVmg) {
+                maxVmg = vmg
+                optimalTwa = twa.toDouble()
+            }
+        }
+        return optimalTwa
+    }
+}
+
+// Represents the complete polar table for a boat, containing multiple PolarCurves for different TWS
+data class PolarTable(val curves: List<PolarCurve>) {
+    init {
+        require(curves.isNotEmpty()) { "PolarTable must have at least one curve." }
+        require(curves.zipWithNext().all { it.first.twS < it.second.twS }) {
+            "PolarCurves in a PolarTable must be sorted by TWS."
+        }
+    }
+
+    /**
+     * Interpolates the target boat speed for a given True Wind Speed (TWS) and True Wind Angle (TWA).
+     */
+    fun interpolateBsp(tws: Double, twa: Double): Double {
+        if (tws <= curves.first().twS) return curves.first().interpolateBsp(twa)
+        if (tws >= curves.last().twS) return curves.last().interpolateBsp(twa)
+
+        for (i in 0 until curves.size - 1) {
+            val c1 = curves[i]
+            val c2 = curves[i + 1]
+            if (tws >= c1.twS && tws <= c2.twS) {
+                val ratio = (tws - c1.twS) / (c2.twS - c1.twS)
+                val bsp1 = c1.interpolateBsp(twa)
+                val bsp2 = c2.interpolateBsp(twa)
+                return bsp1 + ratio * (bsp2 - bsp1)
+            }
+        }
+        return 0.0
+    }
+
+    /**
+     * Finds the optimal upwind TWA for a given TWS by interpolating between curves.
+     */
+    fun findOptimalUpwindTwa(tws: Double): Double {
+        if (tws <= curves.first().twS) return curves.first().findOptimalUpwindTwa()
+        if (tws >= curves.last().twS) return curves.last().findOptimalUpwindTwa()
+
+        for (i in 0 until curves.size - 1) {
+            val c1 = curves[i]
+            val c2 = curves[i + 1]
+            if (tws >= c1.twS && tws <= c2.twS) {
+                val ratio = (tws - c1.twS) / (c2.twS - c1.twS)
+                return c1.findOptimalUpwindTwa() + ratio * (c2.findOptimalUpwindTwa() - c1.findOptimalUpwindTwa())
+            }
+        }
+        return 0.0
+    }
+
+    /**
+     * Finds the optimal downwind TWA for a given TWS by interpolating between curves.
+     */
+    fun findOptimalDownwindTwa(tws: Double): Double {
+        if (tws <= curves.first().twS) return curves.first().findOptimalDownwindTwa()
+        if (tws >= curves.last().twS) return curves.last().findOptimalDownwindTwa()
+
+        for (i in 0 until curves.size - 1) {
+            val c1 = curves[i]
+            val c2 = curves[i + 1]
+            if (tws >= c1.twS && tws <= c2.twS) {
+                val ratio = (tws - c1.twS) / (c2.twS - c1.twS)
+                return c1.findOptimalDownwindTwa() + ratio * (c2.findOptimalDownwindTwa() - c1.findOptimalDownwindTwa())
+            }
+        }
+        return 0.0
+    }
+
+    /**
+     * Calculates the "Polar Percentage" for current boat performance.
+     * Polar % = (Actual BSP / Target BSP) * 100
+     * @return Polar percentage, or 0.0 if target BSP cannot be determined.
+     */
+    fun calculatePolarPercentage(currentTwS: Double, currentTwa: Double, currentBsp: Double): Double {
+        val targetBsp = interpolateBsp(currentTwS, currentTwa)
+        return if (targetBsp > 0) {
+            (currentBsp / targetBsp) * 100.0
+        } else {
+            0.0
+        }
+    }
+}
diff --git a/android-app/app/src/main/kotlin_old/org/terst/nav/PolarDiagramView.kt b/android-app/app/src/main/kotlin_old/org/terst/nav/PolarDiagramView.kt
new file mode 100644
index 0000000..4a678cc
--- /dev/null
+++ b/android-app/app/src/main/kotlin_old/org/terst/nav/PolarDiagramView.kt
@@ -0,0 +1,270 @@
+package org.terst.nav
+
+import android.content.Context
+import android.graphics.Canvas
+import android.graphics.Color
+import android.graphics.Paint
+import android.graphics.RectF
+import android.util.AttributeSet
+import android.view.View
+import kotlin.math.cos
+import kotlin.math.min
+import kotlin.math.sin
+
+class PolarDiagramView @JvmOverloads constructor(
+    context: Context,
+    attrs: AttributeSet? = null,
+    defStyleAttr: Int = 0
+) : View(context, attrs, defStyleAttr) {
+
+    private val gridPaint = Paint().apply {
+        color = Color.parseColor("#404040") // Dark gray for grid lines
+        style = Paint.Style.STROKE
+        strokeWidth = 1f
+        isAntiAlias = true
+    }
+
+    private val textPaint = Paint().apply {
+        color = Color.WHITE
+        textSize = 24f
+        isAntiAlias = true
+        textAlign = Paint.Align.CENTER
+    }
+
+    private val polarCurvePaint = Paint().apply {
+        color = Color.CYAN // Bright color for the polar curve
+        style = Paint.Style.STROKE
+        strokeWidth = 3f
+        isAntiAlias = true
+    }
+
+    private val currentPerformancePaint = Paint().apply {
+        color = Color.RED // Red dot for current performance
+        style = Paint.Style.FILL
+        isAntiAlias = true
+    }
+
+    private val noSailZonePaint = Paint().apply {
+        color = Color.parseColor("#80FF0000") // Semi-transparent red for no-sail zone
+        style = Paint.Style.FILL
+        isAntiAlias = true
+    }
+
+    private val optimalVmgPaint = Paint().apply {
+        color = Color.GREEN // Green for optimal VMG angles
+        style = Paint.Style.STROKE
+        strokeWidth = 4f
+        isAntiAlias = true
+    }
+
+    private var viewCenterX: Float = 0f
+    private var viewCenterY: Float = 0f
+    private var radius: Float = 0f
+
+    // Data for rendering
+    private var polarTable: PolarTable? = null
+    private var currentTws: Double = 0.0
+    private var currentTwa: Double = 0.0
+    private var currentBsp: Double = 0.0
+
+    // Configuration for the diagram
+    private val maxSpeedKnots = 10.0 // Max speed for the outermost circle in knots
+    private val speedCircleInterval = 2.0 // Interval between speed circles in knots
+    private val twaInterval = 30 // Interval between TWA radial lines in degrees
+    private val noSailZoneAngle = 20.0 // Angle +/- from 0 degrees for no-sail zone
+
+    override fun onSizeChanged(w: Int, h: Int, oldw: Int, oldh: Int) {
+        super.onSizeChanged(w, h, oldw, oldh)
+        viewCenterX = w / 2f
+        viewCenterY = h / 2f
+        radius = min(w, h) / 2f * 0.9f // Use 90% of the minimum dimension for radius
+    }
+
+    override fun onDraw(canvas: Canvas) {
+        super.onDraw(canvas)
+
+        // Draw basic diagram elements
+        drawGrid(canvas)
+        drawTwaLabels(canvas)
+        drawNoSailZone(canvas)
+
+        // Draw polar curve if data is available
+        polarTable?.let {
+            drawPolarCurve(canvas, it, currentTws)
+            drawOptimalVmgAngles(canvas, it, currentTws) // Draw optimal VMG angles
+        }
+
+        // Draw current performance if data is available and not zero
+        if (currentTws > 0 && currentTwa > 0 && currentBsp > 0) {
+            drawCurrentPerformance(canvas, currentTwa, currentBsp)
+        }
+    }
+
+    private fun drawGrid(canvas: Canvas) {
+        // Draw TWA radial lines (0 to 360 degrees)
+        for (i in 0 until 360 step twaInterval) {
+            val angleRad = Math.toRadians(i.toDouble())
+            val x = viewCenterX + radius * cos(angleRad).toFloat()
+            val y = viewCenterY + radius * sin(angleRad).toFloat()
+            canvas.drawLine(viewCenterX, viewCenterY, x, y, gridPaint)
+        }
+
+        // Draw speed circles
+        for (i in 0..maxSpeedKnots.toInt() step speedCircleInterval.toInt()) {
+            val currentRadius = (i / maxSpeedKnots * radius).toFloat()
+            canvas.drawCircle(viewCenterX, viewCenterY, currentRadius, gridPaint)
+        }
+    }
+
+    private fun drawTwaLabels(canvas: Canvas) {
+        // Draw TWA labels around the perimeter
+        for (i in 0 until 360 step twaInterval) {
+            val displayAngleRad = Math.toRadians(i.toDouble())
+            // Position the text slightly outside the outermost circle
+            val textX = viewCenterX + (radius + 40) * cos(displayAngleRad).toFloat()
+            // Adjust textY to account for text height, so it's centered vertically on the arc
+            val textY = viewCenterY + (radius + 40) * sin(displayAngleRad).toFloat() + (textPaint.textSize / 3)
+
+            // Map canvas angle (0=right, 90=down) to polar diagram angle (0=up, 90=right)
+            // Example: canvas 270 is polar 0, canvas 0 is polar 90, canvas 90 is polar 180, canvas 180 is polar 270
+            val polarAngle = ( (i + 90) % 360 )
+            canvas.drawText(polarAngle.toString(), textX, textY, textPaint)
+        }
+
+        // Draw speed labels on the horizontal axis
+        for (i in 0..maxSpeedKnots.toInt() step speedCircleInterval.toInt()) {
+            if (i > 0) {
+                val currentRadius = (i / maxSpeedKnots * radius).toFloat()
+                // Left side
+                canvas.drawText(i.toString(), viewCenterX - currentRadius - 10, viewCenterY + (textPaint.textSize / 3), textPaint)
+                // Right side
+                canvas.drawText(i.toString(), viewCenterX + currentRadius + 10, viewCenterY + (textPaint.textSize / 3), textPaint)
+            }
+        }
+    }
+
+    private fun drawNoSailZone(canvas: Canvas) {
+        // The no-sail zone is typically symmetric around the wind direction (0 TWA, which is 'up' on our diagram)
+        // In canvas coordinates, 'up' is -90 degrees or 270 degrees.
+        // So the arc will be centered around 270 degrees.
+        val startAngle = (270 - noSailZoneAngle).toFloat()
+        val sweepAngle = (2 * noSailZoneAngle).toFloat()
+
+        val oval = RectF(viewCenterX - radius, viewCenterY - radius, viewCenterX + radius, viewCenterY + radius)
+        canvas.drawArc(oval, startAngle, sweepAngle, true, noSailZonePaint)
+    }
+
+    private fun drawPolarCurve(canvas: Canvas, polarTable: PolarTable, tws: Double) {
+        val path = android.graphics.Path()
+        var firstPoint = true
+
+        // Generate points for 0 to 180 TWA (starboard side)
+        for (twa in 0..180) {
+            val bsp = polarTable.interpolateBsp(tws, twa.toDouble())
+            if (bsp > 0) {
+                // Map TWA to canvas angle for the starboard side (0 TWA at 270, 90 TWA at 0, 180 TWA at 90)
+                val canvasAngle = (270 + twa).toDouble() % 360
+                val currentRadius = (bsp / maxSpeedKnots * radius).toFloat()
+                val x = viewCenterX + currentRadius * cos(Math.toRadians(canvasAngle)).toFloat()
+                val y = viewCenterY + currentRadius * sin(Math.toRadians(canvasAngle)).toFloat()
+
+                if (firstPoint) {
+                    path.moveTo(x, y)
+                    firstPoint = false
+                } else {
+                    path.lineTo(x, y)
+                }
+            }
+        }
+
+        // Generate points for 0 to -180 TWA (port side) by mirroring
+        // Start from 180 back to 0 to connect the curve
+        for (twa in 180 downTo 0) {
+            val bsp = polarTable.interpolateBsp(tws, twa.toDouble())
+            if (bsp > 0) {
+                // Map negative TWA to canvas angle for the port side (0 TWA at 270, -90 TWA at 180, -180 TWA at 90)
+                val canvasAngle = (270 - twa).toDouble() // This maps TWA 0 to 270, TWA 90 to 180, TWA 180 to 90
+                val currentRadius = (bsp / maxSpeedKnots * radius).toFloat()
+                val x = viewCenterX + currentRadius * cos(Math.toRadians(canvasAngle)).toFloat()
+                val y = viewCenterY + currentRadius * sin(Math.toRadians(canvasAngle)).toFloat()
+
+                path.lineTo(x, y) // Continue drawing the path
+            }
+        }
+        canvas.drawPath(path, polarCurvePaint)
+    }
+
+    private fun drawCurrentPerformance(canvas: Canvas, twa: Double, bsp: Double) {
+        val canvasAngle = if (twa >= 0) {
+            (270 + twa).toDouble() % 360 // Starboard side
+        } else {
+            (270 + twa).toDouble() // Port side (e.g., -30 TWA is 240 canvas angle)
+        }
+
+        val currentRadius = (bsp / maxSpeedKnots * radius).toFloat()
+        val x = viewCenterX + currentRadius * cos(Math.toRadians(canvasAngle)).toFloat()
+        val y = viewCenterY + currentRadius * sin(Math.toRadians(canvasAngle)).toFloat()
+
+        canvas.drawCircle(x, y, 10f, currentPerformancePaint) // Draw a small circle for current performance
+    }
+
+    private fun drawOptimalVmgAngles(canvas: Canvas, polarTable: PolarTable, tws: Double) {
+        // Find optimal upwind TWA
+        val optimalUpwindTwa = polarTable.findOptimalUpwindTwa(tws)
+        if (optimalUpwindTwa > 0) {
+            // Draw a line indicating the optimal upwind TWA (both port and starboard)
+            val upwindBsp = polarTable.interpolateBsp(tws, optimalUpwindTwa)
+            val currentRadius = (upwindBsp / maxSpeedKnots * radius).toFloat() * 1.05f // Slightly longer
+
+            // Starboard side
+            var canvasAngle = (270 + optimalUpwindTwa).toDouble() % 360
+            var x = viewCenterX + currentRadius * cos(Math.toRadians(canvasAngle)).toFloat()
+            var y = viewCenterY + currentRadius * sin(Math.toRadians(canvasAngle)).toFloat()
+            canvas.drawLine(viewCenterX, viewCenterY, x, y, optimalVmgPaint)
+
+            // Port side
+            canvasAngle = (270 - optimalUpwindTwa).toDouble() // Use negative TWA for port side
+            x = viewCenterX + currentRadius * cos(Math.toRadians(canvasAngle)).toFloat()
+            y = viewCenterY + currentRadius * sin(Math.toRadians(canvasAngle)).toFloat()
+            canvas.drawLine(viewCenterX, viewCenterY, x, y, optimalVmgPaint)
+        }
+
+        // Find optimal downwind TWA
+        val optimalDownwindTwa = polarTable.findOptimalDownwindTwa(tws)
+        if (optimalDownwindTwa > 0) {
+            // Draw a line indicating the optimal downwind TWA (both port and starboard)
+            val downwindBsp = polarTable.interpolateBsp(tws, optimalDownwindTwa)
+            val currentRadius = (downwindBsp / maxSpeedKnots * radius).toFloat() * 1.05f // Slightly longer
+
+            // Starboard side
+            var canvasAngle = (270 + optimalDownwindTwa).toDouble() % 360
+            var x = viewCenterX + currentRadius * cos(Math.toRadians(canvasAngle)).toFloat()
+            var y = viewCenterY + currentRadius * sin(Math.toRadians(canvasAngle)).toFloat()
+            canvas.drawLine(viewCenterX, viewCenterY, x, y, optimalVmgPaint)
+
+            // Port side
+            canvasAngle = (270 - optimalDownwindTwa).toDouble() // Use negative TWA for port side
+            x = viewCenterX + currentRadius * cos(Math.toRadians(canvasAngle)).toFloat()
+            y = viewCenterY + currentRadius * sin(Math.toRadians(canvasAngle)).toFloat()
+            canvas.drawLine(viewCenterX, viewCenterY, x, y, optimalVmgPaint)
+        }
+    }
+
+    /**
+     * Sets the polar table data for the view.
+     */
+    fun setPolarTable(table: PolarTable) {
+        this.polarTable = table
+        invalidate() // Redraw the view
+    }
+
+    /**
+     * Sets the current true wind speed, true wind angle, and boat speed.
+     */
+    fun setCurrentPerformance(tws: Double, twa: Double, bsp: Double) {
+        this.currentTws = tws
+        this.currentTwa = twa
+        this.currentBsp = bsp
+        invalidate() // Redraw the view
+    }
+}