ADS-B map: altitude-colored aircraft icons + click-to-show flight trail

Icons were 16px accent-colored glyphs, indistinguishable from OSM's own
airport symbols. Now a 30px outlined airliner silhouette filled on
tar1090/ADS-B Exchange's altitude hue ramp, with a callsign/altitude
hover tooltip; the selected aircraft grows and gets a white outline.

Clicking an aircraft draws the path heard so far, segment-colored by
altitude. c2-core writes one point per position change to
aircraft/{icao}/positions (deduped in-process, writes now concurrent);
points carry expire_at and a TTL fieldOverride deletes them after ~24h.
Trail reads are gated on the parent aircraft doc's org via get(), so the
query needs no org filter or composite index. The latest stretch without
a 20-min gap counts as the current flight.

Verified: c2-core pytest 479 passed; frontend tsc --noEmit clean (node:20
container on radio-box).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

drb-frontend/components/MapView.tsx

@@ -9,13 +9,15 @@ import {
   Polyline,
   Popup,
   TileLayer,
+  Tooltip,
   useMap,
 } from "react-leaflet";
 import L from "leaflet";
-import type { CallRecord, IncidentRecord, NodeRecord, NodeStatus } from "@/lib/types";
+import type { AircraftTrack, CallRecord, IncidentRecord, NodeRecord, NodeStatus } from "@/lib/types";
 import { isKnownSeverity, SEVERITY_COLORS, SEVERITY_LABEL, type Severity } from "@/lib/severity";
 import { MachineOutputNotice } from "@/components/ui/MachineOutputNotice";
 import { useAircraft } from "@/lib/useAircraft";
+import { useAircraftTrail } from "@/lib/useAircraftTrail";
 import { useVessels } from "@/lib/useVessels";
 
 // ── Leaflet icon fix ──────────────────────────────────────────────────────────
@@ -92,36 +94,113 @@ function nodeIcon(status: NodeStatus): L.DivIcon {
   });
 }
 
-// ── Aircraft icon — node-26#9 second-SDR ADS-B overlay ────────────────────────
-function aircraftIcon(trackDeg: number | null): L.DivIcon {
-  const size = 16;
-  const rotation = trackDeg ?? 0;
+// ── Aircraft — node-26#9 second-SDR ADS-B overlay ─────────────────────────────
+// Styled after ADS-B Exchange / tar1090: a sized airliner silhouette with a
+// dark outline, filled by altitude on tar1090's hue ramp, so height reads at a
+// glance and the icon stands out from OSM's own (purple) airport symbols.
+const ALT_HUE_STOPS: [number, number][] = [
+  [0, 20], [2000, 32.5], [4000, 43], [6000, 54], [8000, 72], [9000, 85], [11000, 140], [40000, 300],
+];
+
+function altitudeColor(altFt: number | null): string {
+  if (altFt == null) return "hsl(0, 0%, 55%)";
+  if (altFt <= 0) return "hsl(0, 0%, 45%)"; // on the ground
+  let hue = ALT_HUE_STOPS[ALT_HUE_STOPS.length - 1][1];
+  for (let i = 1; i < ALT_HUE_STOPS.length; i++) {
+    const [a1, h1] = ALT_HUE_STOPS[i];
+    if (altFt <= a1) {
+      const [a0, h0] = ALT_HUE_STOPS[i - 1];
+      hue = h0 + ((h1 - h0) * (altFt - a0)) / (a1 - a0);
+      break;
+    }
+  }
+  return `hsl(${hue.toFixed(0)}, 88%, 48%)`;
+}
+
+const AIRLINER_PATH =
+  "M32 2 C34.2 2 35.2 5 35.2 8 L35.2 23 L61 37.5 L61 42 L35.2 35 L34.2 51 L42.5 57.5 L42.5 61 L32 58.5 " +
+  "L21.5 61 L21.5 57.5 L29.8 51 L28.8 35 L3 42 L3 37.5 L28.8 23 L28.8 8 C28.8 5 29.8 2 32 2 Z";
+
+function aircraftIcon(trackDeg: number | null, altFt: number | null, selected: boolean): L.DivIcon {
+  const size = selected ? 36 : 30;
+  const outline = selected ? "#ffffff" : "#000000";
+  const shadow = selected ? "drop-shadow(0 0 3px #000)" : "drop-shadow(0 1px 1px rgba(0,0,0,.45))";
   return L.divIcon({
     className: "",
-    html: `<div style="width:${size}px;height:${size}px;transform:rotate(${rotation}deg)"><svg width="${size}" height="${size}" viewBox="0 0 24 24" fill="var(--accent)" stroke="var(--surface)" stroke-width="1"><path d="M12 2 L15 11 L22 15 L15 15.5 L14 21 L17 22.5 L12 21.5 L7 22.5 L10 21 L9 15.5 L2 15 L9 11 Z"/></svg></div>`,
+    html:
+      `<div style="width:${size}px;height:${size}px;transform:rotate(${trackDeg ?? 0}deg);filter:${shadow}">` +
+      `<svg width="${size}" height="${size}" viewBox="0 0 64 64"><path d="${AIRLINER_PATH}" ` +
+      `fill="${altitudeColor(altFt)}" stroke="${outline}" stroke-width="${selected ? 3 : 2}" stroke-linejoin="round"/></svg></div>`,
     iconSize: [size, size],
     iconAnchor: [size / 2, size / 2],
   });
 }
 
-function AircraftLayer() {
-  const { aircraft } = useAircraft();
+function AircraftTrail({ icao, current }: { icao: string; current: AircraftTrack }) {
+  const trail = useAircraftTrail(icao);
+  // Extend to the live position so the path always meets the icon.
+  const points = [...trail];
+  if (current.lat != null && current.lon != null) {
+    points.push({ lat: current.lat, lon: current.lon, altitude_ft: current.altitude_ft, t: current.last_seen });
+  }
+  // One segment per leg, colored by altitude like tar1090's track.
   return (
     <>
-      {aircraft
-        .filter((a) => a.lat != null && a.lon != null)
-        .map((a) => (
-          <Marker key={a.icao} position={[a.lat as number, a.lon as number]} icon={aircraftIcon(a.track_deg)}>
-            <Popup minWidth={160}>
-              <div className="space-y-1">
-                <div className="font-semibold">{a.callsign || a.icao}</div>
-                <div className="text-xs text-ink-muted">ICAO {a.icao}</div>
-                {a.altitude_ft != null && <div className="text-xs">Altitude: {Math.round(a.altitude_ft)} ft</div>}
-                {a.ground_speed_kt != null && <div className="text-xs">Speed: {Math.round(a.ground_speed_kt)} kt</div>}
-              </div>
-            </Popup>
-          </Marker>
-        ))}
+      {points.slice(1).map((p, i) => (
+        <Polyline
+          key={`${icao}-${i}`}
+          positions={[[points[i].lat, points[i].lon], [p.lat, p.lon]]}
+          pathOptions={{ color: altitudeColor(p.altitude_ft), weight: 3, opacity: 0.9, lineCap: "round" }}
+          interactive={false}
+        />
+      ))}
+    </>
+  );
+}
+
+function AircraftLayer() {
+  const { aircraft } = useAircraft();
+  const [selected, setSelected] = useState<string | null>(null);
+  const positioned = aircraft.filter((a) => a.lat != null && a.lon != null);
+  const selectedTrack = positioned.find((a) => a.icao === selected);
+
+  return (
+    <>
+      {selectedTrack && <AircraftTrail icao={selectedTrack.icao} current={selectedTrack} />}
+      {positioned.map((a) => (
+        <Marker
+          key={a.icao}
+          position={[a.lat as number, a.lon as number]}
+          icon={aircraftIcon(a.track_deg, a.altitude_ft, a.icao === selected)}
+          zIndexOffset={a.icao === selected ? 1000 : 0}
+          eventHandlers={{
+            click: () => setSelected(a.icao),
+            popupclose: () => setSelected((cur) => (cur === a.icao ? null : cur)),
+          }}
+        >
+          <Tooltip direction="top" offset={[0, -14]}>
+            {a.callsign || a.icao}
+            {a.altitude_ft != null && ` · ${Math.round(a.altitude_ft).toLocaleString()} ft`}
+          </Tooltip>
+          <Popup minWidth={160}>
+            <div className="space-y-1">
+              <div className="font-semibold">{a.callsign || a.icao}</div>
+              <div className="text-xs text-ink-muted">ICAO {a.icao}</div>
+              {a.altitude_ft != null && (
+                <div className="text-xs">
+                  <span
+                    className="inline-block w-2 h-2 rounded-full mr-1 align-middle"
+                    style={{ background: altitudeColor(a.altitude_ft) }}
+                  />
+                  Altitude: {Math.round(a.altitude_ft).toLocaleString()} ft
+                </div>
+              )}
+              {a.ground_speed_kt != null && <div className="text-xs">Speed: {Math.round(a.ground_speed_kt)} kt</div>}
+              {a.track_deg != null && <div className="text-xs">Heading: {Math.round(a.track_deg)}°</div>}
+            </div>
+          </Popup>
+        </Marker>
+      ))}
     </>
   );
 }