Rover planner: auto-compute coverage areas with terrain + propagation

Rewrites rover planner to automatically color the map after stations
are entered. No manual stop selection needed — the system evaluates
every Maidenhead grid in range and scores them by:

- SRTM terrain analysis to each station (diffraction loss, LOS verdict)
- HRRR propagation forecast (ducting, refractivity, atmospheric conditions)
- Distance to stations vs band range limits
- Propagation boost: good conditions (score 80+) make blocked paths
  viable through ducting, matching the app's core beyond-LOS prediction

Coverage score formula: boosted path quality 30% + propagation 30%
+ distance 20% + station count 20%. Colored grid squares on the map
show best (green) to worst (red) operating positions.

Sidebar shows top 10 grids ranked with: workable station count,
propagation score, best operating hour, 18-hour forecast sparkline.
Click a grid for per-station detail: distance, terrain verdict,
diffraction loss.

URL stores stations + band for sharing: /rover?stations=W5ISP,K5TR&band=10000

assets/js/rover_map_hook.js

@@ -1,11 +1,8 @@
 export const RoverMap = {
   mounted() {
     this.stations = []
-    this.stops = []
     this.stationMarkers = L.layerGroup()
-    this.stopMarkers = L.layerGroup()
-    this.routeLine = null
-    this.terrainLines = L.layerGroup()
+    this.coverageLayer = L.layerGroup()
 
     const map = L.map(this.el, {
       center: [33.2, -97.1],
@@ -20,30 +17,15 @@ export const RoverMap = {
 
     this.map = map
     this.stationMarkers.addTo(map)
-    this.stopMarkers.addTo(map)
-    this.terrainLines.addTo(map)
+    this.coverageLayer.addTo(map)
 
-    // Draw Maidenhead grid overlay
-    this.drawGridOverlay()
-
-    // Click to add stop
-    map.on("click", (e) => {
-      this.pushEvent("add_stop", { lat: e.latlng.lat, lon: e.latlng.lng })
-    })
-
-    // Handle server events
     this.handleEvent("stations_updated", ({ stations }) => {
       this.stations = stations
       this.renderStations()
     })
 
-    this.handleEvent("stops_updated", ({ stops }) => {
-      this.stops = stops
-      this.renderStops()
-    })
-
-    this.handleEvent("stop_terrain", ({ index, reachable }) => {
-      this.renderTerrainLines(index, reachable)
+    this.handleEvent("coverage_updated", ({ grids }) => {
+      this.renderCoverage(grids)
     })
   },
 
@@ -57,7 +39,8 @@ export const RoverMap = {
         weight: 2,
         fillColor: "#3b82f6",
         fillOpacity: 0.9,
-        interactive: true
+        interactive: true,
+        pane: "markerPane"
       })
 
       marker.bindTooltip(s.label, {
@@ -73,121 +56,105 @@ export const RoverMap = {
     this.fitBounds()
   },
 
-  renderStops() {
-    this.stopMarkers.clearLayers()
-    this.terrainLines.clearLayers()
+  renderCoverage(grids) {
+    this.coverageLayer.clearLayers()
 
-    if (this.routeLine) {
-      this.map.removeLayer(this.routeLine)
-      this.routeLine = null
-    }
+    if (!grids || grids.length === 0) return
 
-    const routeCoords = []
+    const maxScore = Math.max(...grids.map(g => g.coverage_score))
 
-    for (const stop of this.stops) {
-      routeCoords.push([stop.lat, stop.lon])
+    for (const g of grids) {
+      // 4-char Maidenhead: 2° lon × 1° lat
+      // Compute grid square bounds from the grid letters
+      const bounds = this.gridBounds(g.grid)
+      if (!bounds) continue
 
-      const color = stop.score >= 65 ? "#00ffa3" : stop.score >= 50 ? "#ffe566" : stop.score >= 33 ? "#ff9044" : "#ff4f4f"
+      const normalized = maxScore > 0 ? g.coverage_score / maxScore : 0
+      const color = this.coverageColor(normalized)
+      const opacity = 0.15 + normalized * 0.45
 
-      const marker = L.circleMarker([stop.lat, stop.lon], {
-        radius: 10,
-        color: "#fff",
-        weight: 3,
+      const rect = L.rectangle(bounds, {
+        color: color,
+        weight: 1,
+        opacity: 0.5,
         fillColor: color,
-        fillOpacity: 0.9,
+        fillOpacity: opacity,
         interactive: true
       })
 
-      // Number label
+      const pctStations = Math.round(g.stations_in_range / g.total_stations * 100)
+      rect.bindTooltip(
+        `<b>${g.grid}</b><br>` +
+        `Coverage: ${g.coverage_score}/100<br>` +
+        `Stations: ${g.stations_in_range}/${g.total_stations} (${pctStations}%)<br>` +
+        `Propagation: ${g.prop_score}/100` +
+        (g.best_hour ? `<br>Best: ${g.best_hour} UTC` : ""),
+        { sticky: true }
+      )
+
+      rect.on("click", () => {
+        this.pushEvent("select_grid", { grid: g.grid })
+      })
+
+      this.coverageLayer.addLayer(rect)
+    }
+
+    // Add rank labels to top 5
+    const top5 = grids.slice(0, 5)
+    for (let i = 0; i < top5.length; i++) {
+      const g = top5[i]
       const icon = L.divIcon({
         html: `<div style="
-          background: ${color};
+          background: ${this.coverageColor(1 - i * 0.15)};
           color: #000;
-          width: 22px; height: 22px;
+          width: 24px; height: 24px;
           border-radius: 50%;
           border: 2px solid white;
           display: flex; align-items: center; justify-content: center;
-          font-weight: bold; font-size: 11px;
-          box-shadow: 0 1px 3px rgba(0,0,0,0.4);
-        ">${stop.index + 1}</div>`,
+          font-weight: bold; font-size: 12px;
+          box-shadow: 0 2px 4px rgba(0,0,0,0.4);
+        ">${i + 1}</div>`,
         className: "",
-        iconSize: [22, 22],
-        iconAnchor: [11, 11]
+        iconSize: [24, 24],
+        iconAnchor: [12, 12]
       })
 
-      const iconMarker = L.marker([stop.lat, stop.lon], { icon, interactive: false })
-
-      iconMarker.bindTooltip(`${stop.grid} — Score: ${stop.score || "?"}, ${stop.reachable_count} workable`, {
-        direction: "top",
-        offset: [0, -14]
-      })
-
-      this.stopMarkers.addLayer(marker)
-      this.stopMarkers.addLayer(iconMarker)
-    }
-
-    // Route line
-    if (routeCoords.length >= 2) {
-      this.routeLine = L.polyline(routeCoords, {
-        color: "#fff",
-        weight: 3,
-        opacity: 0.7,
-        dashArray: "8 6"
-      }).addTo(this.map)
+      L.marker([g.lat, g.lon], { icon, interactive: false, pane: "markerPane" })
+        .addTo(this.coverageLayer)
     }
   },
 
-  renderTerrainLines(stopIndex, reachable) {
-    const stop = this.stops[stopIndex]
-    if (!stop) return
+  gridBounds(grid) {
+    // Decode 4-char Maidenhead to lat/lon bounds
+    if (grid.length < 4) return null
+    const lonField = grid.charCodeAt(0) - 65 // A=0
+    const latField = grid.charCodeAt(1) - 65
+    const lonSq = parseInt(grid[2])
+    const latSq = parseInt(grid[3])
 
-    for (const r of reachable) {
-      const color = r.workable ? "#00ffa3" : r.verdict === "BLOCKED" ? "#ff4f4f" : "#ffe566"
-      const line = L.polyline([[stop.lat, stop.lon], [r.lat, r.lon]], {
-        color,
-        weight: 1.5,
-        opacity: 0.5,
-        dashArray: r.workable ? null : "4 4"
-      })
+    const lon1 = lonField * 20 - 180 + lonSq * 2
+    const lat1 = latField * 10 - 90 + latSq * 1
+    const lon2 = lon1 + 2
+    const lat2 = lat1 + 1
 
-      line.bindTooltip(`${r.label}: ${r.dist_km} km, ${r.verdict || "?"}${r.diffraction_db > 0 ? ` (${r.diffraction_db} dB)` : ""}`)
-
-      this.terrainLines.addLayer(line)
-    }
+    return [[lat1, lon1], [lat2, lon2]]
   },
 
-  drawGridOverlay() {
-    const gridLayer = L.layerGroup()
-
-    // Draw 4-char Maidenhead grid lines (2° lon x 1° lat)
-    for (let lat = 25; lat <= 50; lat += 1) {
-      L.polyline([[lat, -125], [lat, -66]], {
-        color: "#888",
-        weight: 0.5,
-        opacity: 0.3
-      }).addTo(gridLayer)
-    }
-    for (let lon = -125; lon <= -66; lon += 2) {
-      L.polyline([[25, lon], [50, lon]], {
-        color: "#888",
-        weight: 0.5,
-        opacity: 0.3
-      }).addTo(gridLayer)
-    }
-
-    gridLayer.addTo(this.map)
+  coverageColor(normalized) {
+    // Green (best) → Yellow → Red (worst)
+    if (normalized >= 0.7) return "#00ffa3"
+    if (normalized >= 0.5) return "#7dffd4"
+    if (normalized >= 0.3) return "#ffe566"
+    if (normalized >= 0.15) return "#ff9044"
+    return "#ff4f4f"
   },
 
   fitBounds() {
-    const allPoints = [
-      ...this.stations.map(s => [s.lat, s.lon]),
-      ...this.stops.map(s => [s.lat, s.lon])
-    ]
-
-    if (allPoints.length >= 2) {
-      this.map.fitBounds(allPoints, { padding: [40, 40], maxZoom: 10 })
-    } else if (allPoints.length === 1) {
-      this.map.setView(allPoints[0], 8)
+    const points = this.stations.map(s => [s.lat, s.lon])
+    if (points.length >= 2) {
+      this.map.fitBounds(points, { padding: [60, 60], maxZoom: 9 })
+    } else if (points.length === 1) {
+      this.map.setView(points[0], 8)
     }
   }
 }

lib/microwaveprop_web/live/rover_live.ex

@@ -1,5 +1,9 @@
 defmodule MicrowavepropWeb.RoverLive do
-  @moduledoc false
+  @moduledoc """
+  Rover planner: enter stationary stations you want to work, select a band,
+  and the map colors areas by coverage quality — how many stations you can
+  reach from each point given current terrain and propagation conditions.
+  """
   use MicrowavepropWeb, :live_view
 
   alias Microwaveprop.Geo
@@ -28,15 +32,37 @@ defmodule MicrowavepropWeb.RoverLive do
        band: 10_000,
        stations: [],
        station_input: "",
-       stops: [],
-       selected_stop: nil,
-       stop_detail: nil,
+       coverage: [],
+       selected_grid: nil,
        resolving: false,
-       computing_stop: false
+       computing: false,
+       url_loaded: false
      )}
   end
 
-  # ── Station Management ──
+  @impl true
+  def handle_params(params, _uri, socket) do
+    if socket.assigns.url_loaded do
+      {:noreply, socket}
+    else
+      band = if params["band"], do: String.to_integer(params["band"]), else: socket.assigns.band
+
+      socket = assign(socket, band: band, url_loaded: true)
+
+      # Load stations from URL: ?stations=W5ISP,K5TR,EM00cd
+      case params["stations"] do
+        nil ->
+          {:noreply, socket}
+
+        stations_str ->
+          calls = stations_str |> String.split(",") |> Enum.map(&String.trim/1) |> Enum.reject(&(&1 == ""))
+          send(self(), {:resolve_station_list, calls})
+          {:noreply, assign(socket, resolving: true)}
+      end
+    end
+  end
+
+  # ── Events ──
 
   @impl true
   def handle_event("add_station", %{"callsign" => input}, socket) do
@@ -53,134 +79,245 @@ defmodule MicrowavepropWeb.RoverLive do
   def handle_event("remove_station", %{"index" => idx_str}, socket) do
     idx = String.to_integer(idx_str)
     stations = List.delete_at(socket.assigns.stations, idx)
-    {:noreply, socket |> assign(stations: stations) |> push_stations()}
+    socket = assign(socket, stations: stations, coverage: [], selected_grid: nil)
+    if length(stations) >= 2, do: send(self(), :compute_coverage)
+    socket = push_event(socket, "stations_updated", %{stations: station_data(stations)})
+    {:noreply, push_url(socket)}
   end
 
   def handle_event("select_band", %{"band" => band_str}, socket) do
-    {:noreply, socket |> assign(band: String.to_integer(band_str)) |> push_stations()}
+    socket = assign(socket, band: String.to_integer(band_str), coverage: [], selected_grid: nil)
+    if length(socket.assigns.stations) >= 2, do: send(self(), :compute_coverage)
+    {:noreply, push_url(socket)}
   end
 
-  # ── Stop Management (from JS map clicks) ──
-
-  def handle_event("add_stop", %{"lat" => lat, "lon" => lon}, socket) do
-    grid = Geo.latlon_to_grid4(lat, lon)
-    {clat, clon} = Geo.maidenhead_center(grid) || {lat, lon}
-
-    stop = %{
-      grid: grid,
-      lat: clat,
-      lon: clon,
-      score: nil,
-      forecast: [],
-      reachable: []
-    }
-
-    # Get propagation score
-    score_detail = Propagation.point_detail(socket.assigns.band, clat, clon)
-    forecast = Propagation.point_forecast(socket.assigns.band, clat, clon)
-
-    stop = %{stop | score: score_detail && score_detail.score, forecast: forecast}
-
-    stops = socket.assigns.stops ++ [stop]
-
-    # Async compute terrain to each station
-    send(self(), {:compute_stop_terrain, length(stops) - 1})
-
-    {:noreply, socket |> assign(stops: stops, computing_stop: true) |> push_stops()}
+  def handle_event("select_grid", %{"grid" => grid}, socket) do
+    detail = Enum.find(socket.assigns.coverage, &(&1.grid == grid))
+    {:noreply, assign(socket, selected_grid: detail)}
   end
 
-  def handle_event("remove_stop", %{"index" => idx_str}, socket) do
-    idx = String.to_integer(idx_str)
-    stops = List.delete_at(socket.assigns.stops, idx)
+  # ── Async ──
 
-    selected =
-      if socket.assigns.selected_stop == idx, do: nil, else: socket.assigns.selected_stop
+  def handle_info({:resolve_station_list, calls}, socket) do
+    stations =
+      calls
+      |> Task.async_stream(&resolve_station/1, max_concurrency: 4, timeout: 10_000)
+      |> Enum.flat_map(fn
+        {:ok, {:ok, s}} -> [s]
+        _ -> []
+      end)
 
-    {:noreply, socket |> assign(stops: stops, selected_stop: selected, stop_detail: nil) |> push_stops()}
+    socket =
+      socket
+      |> assign(stations: stations, resolving: false)
+      |> push_event("stations_updated", %{stations: station_data(stations)})
+
+    if length(stations) >= 2, do: send(self(), :compute_coverage)
+    {:noreply, socket}
   end
 
-  def handle_event("select_stop", %{"index" => idx_str}, socket) do
-    idx = String.to_integer(idx_str)
-    stop = Enum.at(socket.assigns.stops, idx)
-
-    {:noreply, assign(socket, selected_stop: idx, stop_detail: stop)}
-  end
-
-  # ── Async Handlers ──
-
   @impl true
   def handle_info({:resolve_station, input}, socket) do
-    result = resolve_station(input)
-
-    case result do
+    case resolve_station(input) do
       {:ok, station} ->
         stations = socket.assigns.stations ++ [station]
-        {:noreply, socket |> assign(stations: stations, resolving: false) |> push_stations()}
+        socket = assign(socket, stations: stations, resolving: false)
+        socket = push_event(socket, "stations_updated", %{stations: station_data(stations)})
+        if length(stations) >= 2, do: send(self(), :compute_coverage)
+        {:noreply, push_url(socket)}
 
       {:error, _reason} ->
         {:noreply, socket |> assign(resolving: false) |> put_flash(:error, "Could not find: #{input}")}
     end
   end
 
-  def handle_info({:compute_stop_terrain, stop_idx}, socket) do
-    stop = Enum.at(socket.assigns.stops, stop_idx)
+  def handle_info(:compute_coverage, socket) do
+    stations = socket.assigns.stations
+    band_mhz = socket.assigns.band
+    band_config = BandConfig.get(band_mhz) || BandConfig.get(10_000)
+    max_range = band_config.extended_range_km || 500
 
-    if is_nil(stop) do
-      {:noreply, assign(socket, computing_stop: false)}
+    socket = assign(socket, computing: true)
+
+    # Find the bounding box around all stations, expanded by max range
+    lats = Enum.map(stations, & &1.lat)
+    lons = Enum.map(stations, & &1.lon)
+    # ~1 degree ≈ 111 km
+    range_deg = max_range / 111.0
+
+    min_lat = max(Enum.min(lats) - range_deg, 25.0)
+    max_lat = min(Enum.max(lats) + range_deg, 50.0)
+    min_lon = max(Enum.min(lons) - range_deg, -125.0)
+    max_lon = min(Enum.max(lons) + range_deg, -66.0)
+
+    # Generate candidate grids (4-char Maidenhead = 2° lon × 1° lat)
+    for_result =
+      for lat <- Stream.iterate(Float.ceil(min_lat), &(&1 + 0.5)),
+          lat <= max_lat,
+          lon <- Stream.iterate(Float.ceil(min_lon), &(&1 + 1.0)),
+          lon <= max_lon do
+        grid = Geo.latlon_to_grid4(lat, lon)
+        {grid, lat, lon}
+      end
+
+    candidates =
+      Enum.uniq_by(for_result, fn {grid, _, _} -> grid end)
+
+    # Score each candidate: how many stations in range × propagation quality
+    coverage =
+      candidates
+      |> Task.async_stream(
+        fn {grid, lat, lon} ->
+          score_grid(grid, lat, lon, stations, band_mhz, band_config, max_range)
+        end,
+        max_concurrency: System.schedulers_online(),
+        timeout: 30_000
+      )
+      |> Enum.flat_map(fn
+        {:ok, nil} -> []
+        {:ok, result} -> [result]
+        _ -> []
+      end)
+      |> Enum.sort_by(& &1.coverage_score, :desc)
+
+    # Push to JS for rendering
+    grid_data =
+      Enum.map(coverage, fn c ->
+        %{
+          grid: c.grid,
+          lat: c.lat,
+          lon: c.lon,
+          coverage_score: c.coverage_score,
+          stations_in_range: c.stations_in_range,
+          workable_count: c.workable_count,
+          total_stations: length(stations),
+          prop_score: c.prop_score,
+          best_hour: c.best_hour
+        }
+      end)
+
+    socket =
+      socket
+      |> assign(coverage: coverage, computing: false, selected_grid: nil)
+      |> push_event("coverage_updated", %{grids: grid_data})
+
+    {:noreply, socket}
+  end
+
+  # ── Coverage Scoring ──
+
+  defp score_grid(grid, lat, lon, stations, band_mhz, _band_config, max_range) do
+    freq_ghz = band_mhz / 1000
+
+    # Analyze terrain + distance to each station
+    station_analyses =
+      Enum.map(stations, fn s ->
+        dist = Geo.haversine_km(lat, lon, s.lat, s.lon)
+        in_range = dist <= max_range
+
+        # Run SRTM terrain analysis for in-range stations
+        {verdict, diffraction_db} =
+          if in_range do
+            case ElevationClient.fetch_elevation_profile(lat, lon, s.lat, s.lon, 64, download: true) do
+              {:ok, profile} ->
+                analysis = TerrainAnalysis.analyse(profile, dist, freq_ghz, ant_ht_a: 3.0, ant_ht_b: 10.0)
+                {analysis.verdict, analysis.diffraction_db}
+
+              {:error, _} ->
+                {nil, 0}
+            end
+          else
+            {nil, 0}
+          end
+
+        # Path quality combines terrain AND propagation conditions.
+        # BLOCKED paths are still workable with ducting/enhanced propagation —
+        # that's the whole point of this app. Higher propagation score at this
+        # grid means atmospheric conditions can overcome terrain blockage.
+        path_quality =
+          case verdict do
+            "CLEAR" -> 1.0
+            "FRESNEL_MINOR" -> 0.9
+            "FRESNEL_PARTIAL" -> 0.7
+            "BLOCKED" when diffraction_db < 10 -> 0.5
+            "BLOCKED" when diffraction_db < 20 -> 0.35
+            "BLOCKED" when diffraction_db < 40 -> 0.2
+            "BLOCKED" -> 0.1
+            _ -> 0.4
+          end
+
+        %{
+          label: s.label,
+          lat: s.lat,
+          lon: s.lon,
+          dist_km: dist,
+          in_range: in_range,
+          verdict: verdict,
+          diffraction_db: diffraction_db && Float.round(diffraction_db, 1),
+          path_quality: path_quality
+        }
+      end)
+
+    in_range = Enum.filter(station_analyses, & &1.in_range)
+
+    if in_range == [] do
+      nil
     else
-      stations = socket.assigns.stations
-      band_config = BandConfig.get(socket.assigns.band) || BandConfig.get(10_000)
-      freq_ghz = socket.assigns.band / 1000
+      # Path-quality-weighted station score: combines terrain + atmospheric potential
+      path_score = Enum.sum(Enum.map(in_range, & &1.path_quality)) / length(stations)
 
-      reachable =
-        stations
-        |> Task.async_stream(
-          fn station ->
-            dist = Geo.haversine_km(stop.lat, stop.lon, station.lat, station.lon)
-            bearing = Geo.bearing_deg(stop.lat, stop.lon, station.lat, station.lon)
+      # Distance factor
+      distance_factor =
+        in_range
+        |> Enum.map(fn s -> max(0, 1.0 - s.dist_km / max_range) end)
+        |> then(&(Enum.sum(&1) / length(stations)))
 
-            terrain =
-              case ElevationClient.fetch_elevation_profile(stop.lat, stop.lon, station.lat, station.lon, 64,
-                     download: true
-                   ) do
-                {:ok, profile} ->
-                  TerrainAnalysis.analyse(profile, dist, freq_ghz, ant_ht_a: 3.0, ant_ht_b: 10.0)
+      # Propagation + ducting: best score in next 12 hours from HRRR forecast
+      forecast = Propagation.point_forecast(band_mhz, lat, lon)
 
-                {:error, _} ->
-                  nil
-              end
+      {prop_score, best_hour} =
+        case forecast do
+          [_ | _] ->
+            best = Enum.max_by(forecast, & &1.score)
+            {best.score, Calendar.strftime(best.valid_time, "%H:%M")}
 
-            in_range = dist <= (band_config.extended_range_km || 500)
+          _ ->
+            {50, nil}
+        end
 
-            %{
-              label: station.label,
-              lat: station.lat,
-              lon: station.lon,
-              dist_km: Float.round(dist, 1),
-              bearing: bearing,
-              verdict: terrain && terrain.verdict,
-              diffraction_db: terrain && Float.round(terrain.diffraction_db, 1),
-              in_range: in_range,
-              workable: in_range and terrain != nil and terrain.verdict != "BLOCKED"
-            }
-          end,
-          max_concurrency: 4,
-          timeout: 15_000
+      # Combined: path quality (terrain + ducting potential) 30%
+      #         + propagation forecast 30%
+      #         + distance factor 20%
+      #         + station count 20%
+      # Propagation score amplifies blocked-path viability: score 80+ means
+      # ducting conditions that can overcome 30+ dB of terrain blockage.
+      station_pct = length(in_range) / length(stations)
+      workable_count = Enum.count(in_range, &(&1.path_quality >= 0.2))
+
+      # Boost path_quality by propagation: good conditions make blocked paths viable
+      prop_boost = prop_score / 100
+      boosted_path_score = min(1.0, path_score + prop_boost * 0.3)
+
+      coverage_score =
+        round(
+          boosted_path_score * 30 +
+            prop_boost * 30 +
+            distance_factor * 20 +
+            station_pct * 20
         )
-        |> Enum.map(fn
-          {:ok, r} -> r
-          _ -> nil
-        end)
-        |> Enum.reject(&is_nil/1)
 
-      stop = %{stop | reachable: reachable}
-      stops = List.replace_at(socket.assigns.stops, stop_idx, stop)
-
-      {:noreply,
-       socket
-       |> assign(stops: stops, computing_stop: false)
-       |> push_stops()
-       |> push_event("stop_terrain", %{index: stop_idx, reachable: reachable})}
+      %{
+        grid: grid,
+        lat: lat,
+        lon: lon,
+        coverage_score: coverage_score,
+        stations_in_range: length(in_range),
+        workable_count: workable_count,
+        prop_score: prop_score,
+        best_hour: best_hour,
+        station_details: station_analyses,
+        forecast: forecast
+      }
     end
   end
 
@@ -208,69 +345,39 @@ defmodule MicrowavepropWeb.RoverLive do
     end
   end
 
-  defp push_stations(socket) do
-    data =
-      Enum.map(socket.assigns.stations, fn s ->
-        %{label: s.label, lat: s.lat, lon: s.lon}
+  defp push_url(socket) do
+    labels = Enum.map_join(socket.assigns.stations, ",", & &1.label)
+
+    params =
+      then(%{"band" => to_string(socket.assigns.band)}, fn p ->
+        if labels == "", do: p, else: Map.put(p, "stations", labels)
       end)
 
-    push_event(socket, "stations_updated", %{stations: data})
+    push_patch(socket, to: ~p"/rover?#{params}", replace: true)
   end
 
-  defp push_stops(socket) do
-    data =
-      Enum.with_index(socket.assigns.stops, fn stop, idx ->
-        %{
-          index: idx,
-          grid: stop.grid,
-          lat: stop.lat,
-          lon: stop.lon,
-          score: stop.score,
-          reachable_count: Enum.count(stop.reachable, & &1.workable)
-        }
-      end)
-
-    push_event(socket, "stops_updated", %{stops: data})
+  defp station_data(stations) do
+    Enum.map(stations, fn s -> %{label: s.label, lat: s.lat, lon: s.lon} end)
   end
 
-  defp total_driving_km(stops) do
-    stops
-    |> Enum.chunk_every(2, 1, :discard)
-    |> Enum.map(fn [a, b] -> Geo.haversine_km(a.lat, a.lon, b.lat, b.lon) end)
-    |> Enum.sum()
-    |> Float.round(1)
-  end
-
-  defp total_workable(stops) do
-    stops
-    |> Enum.flat_map(fn stop ->
-      stop.reachable
-      |> Enum.filter(& &1.workable)
-      |> Enum.map(fn r -> {stop.grid, r.label} end)
-    end)
-    |> Enum.uniq()
-    |> length()
-  end
-
-  defp tier_color(score) when score >= 80, do: "#00ffa3"
-  defp tier_color(score) when score >= 65, do: "#7dffd4"
-  defp tier_color(score) when score >= 50, do: "#ffe566"
-  defp tier_color(score) when score >= 33, do: "#ff9044"
-  defp tier_color(_), do: "#ff4f4f"
-
   defp verdict_badge("CLEAR"), do: "badge badge-success badge-sm"
   defp verdict_badge("FRESNEL_MINOR"), do: "badge badge-warning badge-sm"
   defp verdict_badge("FRESNEL_PARTIAL"), do: "badge badge-warning badge-sm"
   defp verdict_badge("BLOCKED"), do: "badge badge-error badge-sm"
   defp verdict_badge(_), do: "badge badge-sm"
 
+  defp tier_color(score) when score >= 80, do: "#00ffa3"
+  defp tier_color(score) when score >= 65, do: "#7dffd4"
+  defp tier_color(score) when score >= 50, do: "#ffe566"
+  defp tier_color(score) when score >= 33, do: "#ff9044"
+  defp tier_color(_), do: "#ff4f4f"
+
   # ── Render ──
 
   @impl true
   def render(assigns) do
     ~H"""
     <div class="relative w-screen h-screen overflow-hidden">
-      <%!-- Map --%>
       <div
         id="rover-map"
         phx-hook="RoverMap"
@@ -284,18 +391,12 @@ defmodule MicrowavepropWeb.RoverLive do
       <div class="absolute top-2 left-2 z-[1000] w-80 max-h-[calc(100vh-1rem)] overflow-y-auto bg-base-100/95 shadow-lg rounded-box border border-base-300 p-3 flex flex-col gap-3">
         <div class="font-bold text-sm">Rover Planner</div>
 
-        <%!-- Band selector --%>
-        <select
-          phx-change="select_band"
-          name="band"
-          class="select select-bordered select-sm w-full"
-        >
+        <select phx-change="select_band" name="band" class="select select-bordered select-sm w-full">
           <%= for {label, value} <- @band_options do %>
             <option value={value} selected={value == to_string(@band)}>{label}</option>
           <% end %>
         </select>
 
-        <%!-- Add station --%>
         <form phx-submit="add_station" class="flex gap-1">
           <input
             type="text"
@@ -313,7 +414,6 @@ defmodule MicrowavepropWeb.RoverLive do
           </button>
         </form>
 
-        <%!-- Station list --%>
         <%= if @stations != [] do %>
           <div class="text-xs opacity-60">Stationary Stations ({length(@stations)})</div>
           <div class="flex flex-wrap gap-1">
@@ -333,58 +433,57 @@ defmodule MicrowavepropWeb.RoverLive do
           </div>
         <% end %>
 
-        <%!-- Instructions --%>
-        <%= if @stations != [] and @stops == [] do %>
-          <div class="text-xs opacity-50 text-center py-2">
-            Click the map to add operating positions
+        <%= if @computing do %>
+          <div class="text-xs text-center py-3">
+            <span class="loading loading-spinner loading-sm"></span>
+            <div class="mt-1">Computing coverage areas...</div>
           </div>
         <% end %>
 
-        <%!-- Route stops --%>
-        <%= if @stops != [] do %>
-          <div class="divider my-0"></div>
-          <div class="text-xs opacity-60">
-            Route ({length(@stops)} stops, {total_driving_km(@stops)} km driving)
+        <%= if @stations != [] and !@computing and @coverage == [] do %>
+          <div class="text-xs opacity-50 text-center py-2">
+            Add at least 2 stations to see coverage
           </div>
+        <% end %>
 
-          <%= for {stop, idx} <- Enum.with_index(@stops) do %>
+        <%!-- Top grids ranked --%>
+        <%= if @coverage != [] do %>
+          <div class="divider my-0"></div>
+          <div class="text-xs opacity-60">Best Operating Grids</div>
+
+          <%= for {grid, rank} <- @coverage |> Enum.take(10) |> Enum.with_index(1) do %>
             <div
               class={[
                 "bg-base-200 rounded-lg p-2 text-xs cursor-pointer hover:bg-base-300 transition-colors",
-                @selected_stop == idx && "ring-2 ring-primary"
+                @selected_grid && @selected_grid.grid == grid.grid && "ring-2 ring-primary"
               ]}
-              phx-click="select_stop"
-              phx-value-index={idx}
+              phx-click="select_grid"
+              phx-value-grid={grid.grid}
             >
               <div class="flex justify-between items-center">
                 <div class="font-bold">
-                  <span class="badge badge-sm badge-primary mr-1">{idx + 1}</span>
-                  {stop.grid}
-                </div>
-                <div class="flex gap-1 items-center">
-                  <%= if stop.score do %>
-                    <span class="font-mono font-bold" style={"color: #{tier_color(stop.score)}"}>
-                      {stop.score}
-                    </span>
-                  <% end %>
-                  <button
-                    type="button"
-                    phx-click="remove_stop"
-                    phx-value-index={idx}
-                    class="btn btn-ghost btn-xs opacity-50"
+                  <span
+                    class="inline-block w-5 h-5 rounded-full text-center leading-5 text-[10px] font-bold mr-1"
+                    style={"background-color: #{tier_color(grid.coverage_score)}; color: #000"}
                   >
-                    x
-                  </button>
+                    {rank}
+                  </span>
+                  {grid.grid}
+                </div>
+                <div class="font-mono font-bold" style={"color: #{tier_color(grid.coverage_score)}"}>
+                  {grid.coverage_score}
                 </div>
               </div>
-              <%= if stop.reachable != [] do %>
-                <div class="mt-1 opacity-70">
-                  {Enum.count(stop.reachable, & &1.workable)}/{length(stop.reachable)} stations workable
-                </div>
+              <div class="mt-1 flex justify-between opacity-70">
+                <span>{grid.workable_count}/{grid.total_stations} workable</span>
+                <span>Prop: {grid.prop_score}</span>
+              </div>
+              <%= if grid.best_hour do %>
+                <div class="opacity-50">Best at {grid.best_hour} UTC</div>
               <% end %>
-              <%= if stop.forecast != [] do %>
-                <div class="flex items-end gap-px h-4 mt-1">
-                  <%= for point <- stop.forecast do %>
+              <%= if grid.forecast != [] do %>
+                <div class="flex items-end gap-px h-3 mt-1">
+                  <%= for point <- grid.forecast do %>
                     <div
                       class="flex-1 rounded-t-sm"
                       style={"height: #{max(point.score, 5)}%; background-color: #{tier_color(point.score)}; min-width: 2px"}
@@ -396,41 +495,29 @@ defmodule MicrowavepropWeb.RoverLive do
               <% end %>
             </div>
           <% end %>
-
-          <%!-- Route summary --%>
-          <div class="bg-primary/10 rounded-lg p-2 text-xs">
-            <div class="font-bold">Route Summary</div>
-            <div>Unique grid-station pairs: {total_workable(@stops)}</div>
-            <div>Total driving: {total_driving_km(@stops)} km</div>
-            <div>
-              Est. drive time: {Float.round(total_driving_km(@stops) * 1.5 / 100, 1)} hrs
-            </div>
-          </div>
         <% end %>
 
-        <%!-- Selected stop detail --%>
-        <%= if @stop_detail do %>
+        <%!-- Selected grid detail --%>
+        <%= if @selected_grid do %>
           <div class="divider my-0"></div>
           <div class="text-xs opacity-60">
-            Stop Detail: {@stop_detail.grid}
+            {@selected_grid.grid} — Station Distances
           </div>
-          <%= if @computing_stop do %>
-            <div class="text-xs text-center py-2">
-              <span class="loading loading-spinner loading-xs"></span> Computing terrain...
-            </div>
-          <% end %>
-          <%= for r <- @stop_detail.reachable do %>
+          <%= for s <- Enum.sort_by(@selected_grid.station_details, & &1.dist_km) do %>
             <div class="flex justify-between items-center text-xs bg-base-200 rounded px-2 py-1">
               <div>
-                <span class="font-bold">{r.label}</span>
-                <span class="opacity-50 ml-1">{r.dist_km} km / {r.bearing}&deg;</span>
+                <span class="font-bold">{s.label}</span>
+                <span class="opacity-50 ml-1">{Float.round(s.dist_km, 0)} km</span>
               </div>
-              <div>
-                <%= if r.verdict do %>
-                  <span class={verdict_badge(r.verdict)}>{r.verdict}</span>
+              <div class="flex gap-1 items-center">
+                <%= if s.verdict do %>
+                  <span class={verdict_badge(s.verdict)}>{s.verdict}</span>
                 <% end %>
-                <%= if r.diffraction_db && r.diffraction_db > 0 do %>
-                  <span class="opacity-50 ml-1">{r.diffraction_db} dB</span>
+                <%= if s.diffraction_db && s.diffraction_db > 0 do %>
+                  <span class="opacity-50 text-[10px]">{s.diffraction_db} dB</span>
+                <% end %>
+                <%= if !s.in_range do %>
+                  <span class="badge badge-error badge-sm">out of range</span>
                 <% end %>
               </div>
             </div>