05 — Map, track rendering, barogram and airspace (iOS → Android)

Note

Written for the Android port and describes iOS build 559. iOS builds 560–564 changed parts of the flight map; see decisions §17.

Source analysed: /Users/fousa/Projects/vulture-ios (read-only), as of 2026-10-10. Paths below are relative to that repo. Map/ = Modules/App/Sources/Map/. No secrets are reproduced; where a key/token is configured, only its location is given.

Contents

1. Mapbox setup (SDK, styles, projection, chrome, events, gestures, camera, offline, 3D status)
2. Style layers: full IDs and z-order
3. Flight track rendering (styles, colouring, simplification, thermals, events, glider, task/OZ, multi-flight, highlight)
4. Barogram (implementation, series, axes, gestures, scrubber, sync, playback, panel)
5. Airspace (sources, parsers, model, settings, styling, selection, detail sheet, infringements)
6. Other map data (waypoints, airports, terrain/elevation, satellite clouds, measure tool)
7. Colour reference (all tokens)
8. Android mapping (Mapbox Android v11 + Compose equivalents, barogram recommendation, token handling)
9. Quirks to replicate or fix deliberately
10. Risks and size estimate

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1. Mapbox setup

1.1 SDK

Item	iOS value	Source
SDK	MapboxMaps 11.32.0, pinned exactVersion via SPM	XcodeGen/Packages/MapboxMaps.yml
Migration	v6 → v11 swapped 2026-09-01; per-feature verification tracker	Docs/mapbox-v11-feature-checklist.md
Access token	MBXAccessToken key in Modules/App/Resources/Info.plist (public pk. token, hard-coded)	Info.plist:107
SPI imports	@_spi(Restricted) (hide logo/attribution), @_spi(Experimental)	Map/Rendering/Compat/MapCompatMapView.swift
Architecture	Controllers are Mapbox-free; MapViewDataSource (base) + Flight/Task/InFlight subclasses own the map, sources, layers, annotations. One factory enum per layer under Map/Rendering/Layers/. A “compat” layer keeps v6-shaped types (MGLShapeSource, MGL*Feature) bridging to v11.	CLAUDE.md “Map integration (MapboxMaps v11)”

Rules from CLAUDE.md worth carrying over verbatim to Android:

• Layers are values; never hold one to mutate later. For per-frame/gesture-driven changes set one property (setStyleLayerProperty(id, "line-opacity", …)) instead of a whole updateLayer (measured 0.3–0.55 ms per updateLayer vs ~300× cheaper single-property set).
• Feature queries are async-only (never block the main thread to fake a sync query).
• Camera-changed fires per frame in v11 → the “did change” hook is debounced 200 ms; “is changing” stays immediate (MapViewDataSource.swift setupBindings, +Delegate.swift).
• GeoJSON numbers come back as Double; read feature attributes tolerantly.
• Shape pushes to GeoJSON sources are coalesced to ~30 Hz (1/30 s with trailing push) (Map/Rendering/Compat/MapCompatSources.swift:124-141).

1.2 Styles

Packages/Preferences/.../Models/MapStyle.swift (Int raw values persisted, key VultureMapStyle):

MapStyle (raw)	Style URL	Notes
adaptive (0, default when unset)	mapbox://styles/mapbox/light-v11 / mapbox://styles/mapbox/dark-v11 by UI appearance	Re-applies style URL on light/dark change (MapView.swift invalidateTraits)
outdoor (1)	mapbox://styles/mapbox/outdoors-v12
satellite (2)	mapbox://styles/mapbox/satellite-v9
streets (3)	mapbox://styles/mapbox/streets-v12
standard (4)	mapbox://styles/mapbox/standard	After every style load and on appearance change: `setStyleImportConfigProperty(“basemap”, “lightPreset”, “day”

Sources: Map/Rendering/Compat/MapCompatMapView.swift:22-31, Map/Extensions/MapStyle+URL.swift, Map/Extensions/UITraitCollection+Style.swift, Map/MapView.swift.

Map-style-dependent colours: overlay label/glider colours resolve light on outdoor/streets, dark/white on satellite, dynamic on adaptive/standard (Map/Extensions/UIColor+Theme.swift:28-39, 93-106). Android must reproduce this: pick colour by (mapStyle, isSystemDark).

Picker thumbnails: debug launch arg -VultureProbeStyleThumbnail frames Terlet (52.0567, 5.9192) zoom 11, crop 800×500 (MapViewDataSource+Delegate.swift). Reuse the same images on Android.

1.3 Per-style-load setup (MapViewDataSource+Delegate.swift styleDidLoad)

On every style load (style-scoped things are lost on style switch):

1. setProjection(globe) — globe when zoomed out, Mercator at flying zooms.
2. Add file-airspace source + layers; waypoint + home-waypoint sources + layers.
3. If OpenAIP airspace active: add OpenAIP tile source + layers, hide file-airspace layers.
4. Re-render parsed files only if shapes are nil (otherwise re-add from held shapes).
5. Re-apply highlighted airspace, weather overlay.
6. Register style images: legend numerals "0","5",…,"100", photo (SF photo, template), photos (SF photo.on.rectangle.fill), question, direction, pill, bs_0..bs_2, generated significant-weather patterns.
7. Fade the map in: alpha 0 → 1, 0.35 s easeInOut (MapViewDataSource.presentMap).

Map chrome: logo and attribution hidden (hideMapboxChrome; attribution is shown in About instead, telemetry opt-out in Settings). Compass margins (16,16). isPitchEnabled = false on every map. Background while loading: systemGroupedBackground. A loading pill (“Loading map…”) scales 0.7↔1 and fades, spring 0.5 s damping 0.7 velocity 0.4.

Android note: hiding the Mapbox logo/attribution is a ToS matter; on iOS it relies on restricted SPI. On Android logo.enabled=false / attribution.enabled=false are public but the Mapbox ToS still requires attribution somewhere — keep it in About as iOS does and confirm with the account terms.

1.4 Initial camera, centring and padding

Behaviour	Value	Source
Initial centre	Homebase, else fallback 48.1049991, 8.7470783, zoom 9	MapViewDataSource.swift, +Center.swift
Animated camera	camera.ease(duration: 0.3)	MapCompatMapView.swift ease()
Fit to shapes	mapboxMap.camera(for: coords, camera: CameraOptions(), coordinatesPadding: edgePadding, maxZoom: nil, offset: nil) then ease 0.3 s	MapCompatMapView.swift showAnnotations
Edge padding	top max(safeTop, 56) + 16, left safeLeft + 16, bottom max(safeBottom,0) + bottomPadding + 16, right safeRight + 16	MapViewDataSource+Center.swift
bottomPadding	height of open sheet (thermal/chat/airspace) + 8, else the graph panel height	FlightMapViewController.swift:506-520
Centre on point radius	builds a 5°-sampled circle polygon of radius r and fits it	+Center.swift center(coordinate:radius:)
Radii used	glider 5000 m; fix/thermal 2000 m; pinned-follow 10000 m	FlightMapViewDataSource.swift:141-143, +Center.swift:47-61
Airspace centre	padding 60 pt each side + sheet height at bottom	MapViewDataSource+Airspace.swift:145-175
Zoom keys	⌘+/⌘− = zoom ±1 animated	+Center.swift zoom(by:)
Resize/rotation	keepVisibleRegion: if map still where a centring left it, re-frame framedShape into the new free area; else keep zoom and the point at the middle of the free area (Web-Mercator math in Packages/Map/.../Viewport/MapViewport+Reframing.swift)	CLAUDE.md
Viewport handoff	MapViewport{center, zoom, bearing, size}; zoom(fitting:) = zoom + log2(min(w'/w, h'/h))	Packages/Map/.../Viewport/MapViewport.swift

Follow during replay (“Pinned”, pref VulturePinned, default off): no continuous follow. On each position update, if the selected glider’s screen point leaves the map rect inset by edgePadding, the camera frames a 10 km radius around it (animated). Scrubbing otherwise never moves the camera.

1.5 Gestures (MapViewDataSource+Gestures.swift)

Gesture	Action
Pan / pinch / rotate	Mapbox defaults; pitch disabled
Long-press (1 finger)	Airspace query at point (default)
Tap	Airspace query only while the airspace sheet is open (airspaceGestureType = .tap)
Two-finger long-press (+drag)	Measure tool (line + end dots + rotated distance pill). Cancelled by any camera movement
Tap on thermal / photo (flight map)	44×44 pt rect query: photos first (photos.layer, photos.labels), then thermals.fill
Tap on glider annotation	Select that flight (light impact haptic)
Right-click / scroll-wheel / trackpad zoom	Desktop only — skip on Android (or map to mouse wheel on ChromeOS)
Left edge strip	Guard so swipe-back wins over map pan — Android equivalent: predictive back gesture handles this automatically
Weather tap halves	Left/right half steps SkySight period (task/in-flight maps only)

App recognisers are prioritised over Mapbox’s own tap/long-press recognisers. Android: use mapView.gestures.addOnMapLongClickListener / addOnMapClickListener and return true to consume; measure tool requires a custom two-pointer long-press detector on top of the MapView (Compose pointerInput overlay that passes through otherwise).

1.6 Offline, terrain, 3D

• No offline map support (no OfflineManager, TileStore, style packs anywhere). Only the satellite-cloud raster tiles are pre-downloaded and served from a disk cache via an HTTP interceptor (§6.4).
• No terrain / DEM / pitch in the map today. Docs/3d-map-investigation.md is a design (2D/3D toggle, chase/cockpit/free camera, lineZOffset elevated track, fill-extrusion wall-mode airspace, ModelLayer glider, 100 pt scrubber panel state, competition “Field” camera). Not implemented — Android should not build it in v1 but should keep the track data shaped so it can be added (per-segment features with an altitude property).
• Race ranking (RaceProgress/RaceRanking in Flights, RaceRankingView in FlightScreens) is built on branch feature/race-ranking (2026-10-09) on the flat map; ranks by average speed since own start (min divisor 15 min). Out of scope here but it hooks into the same replay clock.

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2. Style layers — IDs and z-order

Suffix helpers (Map/Extensions/String+Identifiers.swift:129-152): .layer, .labels, .fill, .border, .border.dashed, .border.inner.

Flight map, bottom → top (all addLayer on top unless noted):

#	Layer ID	Type	Source
1	airspace.fill	fill	airspace (GeoJSON)
2	airspace.border.inner	line	airspace
3	airspace.border.dashed	line	airspace
4	airspace.border	line	airspace
5	waypoints.layer, waypoints.labels	circle, symbol	waypoints
6	homeWaypoint.layer, homeWaypoint.labels	circle, symbol	homeWaypoint
7	openAIPAirspace.fill.tap, .fill, .fill.blue, .border.inner, .border.dashed, .border (only when OpenAIP active)	fill/line	openAIPAirspace (vector)
8	airspace.highlight.fill, airspace.highlight.border (OpenAIP highlight only)	fill, line	openAIPAirspace
—	Weather/SkySight layers	raster	inserted below airspace.border.dashed (MGLStyle+Layers.swift:34-43)
9	thermals.fill	fill	thermals
10	task.border.dashed, task.fill, task.border	line, fill, line	task
—	satellite.<unix>.layer (cloud frames)	raster	inserted below the first layer whose id contains "flight"
11	flight.<hash>.layer (one per loaded flight)	line	flight.<hash>; each inserted below selectedFlight
12	selectedFlight (layer id = source id)	line	selectedFlight
13	coloredFlight.layer	line	coloredFlight
14	track.layer (distance optimisation)	line dotted	track
15	optimizedTask.layer (best task attempt)	line dotted	optimizedTask
16	events.layer, events.labels	circle, symbol	events
17	photos.fill, photos.layer, photos.labels	circle, symbol	photos (clustered)
18	measure, measure.layer, measureMeta.labels	line, circle, symbol	measure sources
19	highlight.layer then highlight.border (added on demand, on top)	line	highlight
top	View annotations: gliders, airspace query marker	Android ViewAnnotationManager

Task map: task.fill, task.border, task.layer, taskMetadata.labels, taskMetadata.layer, measure. In-flight map: flight.layer (.inflight style; features chunked per 200 fixes, ids track.<i>).

GeoJSON source options (MapCompatSources.swift):

Option set	maxzoom	buffer	lineMetrics	tolerance
.track	16	64	false	default 0.375
.task	16	default (128)	false	default
.airspace	14	64	false	default
coloredFlight	track opts		false	0.0
photos				cluster true, clusterRadius 35

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3. Flight track rendering

3.1 Line layer factory (Map/Rendering/Layers/LineStyleLayer.swift)

All: line-join round, line-cap round (except .inflight). Width = ["interpolate", ["linear"], ["zoom"], 9, low, 14, high]. Data-driven colour key "color".

LineType	Width z9 → z14	Colour	Other	Used for
.line	0.8 → 1.5	flight colour (constant)		every loaded flight (thin)
.border	1.6 → 3.0	flightColor.darken(0.2) set after creation		selected flight, plain mode
.color	1.6 → 3.0	["get","color"]		altitude-coloured selected flight
.inflight	2.4 → 4.5	Flight 1 #4A6FA0	join miter, cap butt, opacity 0.5	live in-flight track
.highlight	1.6 → 3.0	#D5A359		graph/leg highlight
.highlightBorder	2.6 → 4.0	#D5A359 darkened
.infrigement (sic)	1.6 → 3.0	#ED5656		infringement highlight
.infrigementBorder	2.6 → 4.0	#ED5656 darkened (≈#BA2323)

Dotted layers (FlightTrackLineStyleLayer.swift:15-31): round join/cap, width interpolate linear zoom 8 → 1.6, 14 → 3.0 (stop at zoom 8), line-dasharray [1, 2], constant colour:

• track.layer → brand Tint #DF774A (distance optimisation polyline, chosen by VultureTrackOptimization: out / outAndReturn / triangle / threeTurnpoints / fiveTurnpoints(=free), default fiveTurnpoints).
• optimizedTask.layer → Success #519672 (best task attempt fixes).

darken(ratio: 0.2): subtract 0.2 from each of R,G,B (0…1), floor 0, keep alpha (Packages/DesignSystem/.../UIColor+Helpers.swift:34-46).

3.2 Colouring modes

Only two modes exist. There is no vario, speed or phase colouring on the map.

Mode	Pref	Rendering
Plain (default)	VultureShowColoredTrack = false	Source selectedFlight: one LineString of all fixes; colour flightColor.darken(), width 1.6→3.0
By altitude	VultureShowColoredTrack = true	Source coloredFlight (tolerance 0): per-segment LineString features each with color property; layer coloredFlight.layer uses ["get","color"]. Not a line-gradient

Switch: FlightMapViewDataSource+Highlight.swift:40-56. Any pref change re-runs select(flightViewModel:).

Altitude ramp (Map/Extensions/Flight+Polylines.swift:87-142) — index 0 = min pressure altitude, 10 = max:

idx	RGB (0–1)	Hex
0	1.00, 0.00, 0.00	#FF0000
1	1.00, 0.39, 0.00	#FF6300
2	1.00, 0.78, 0.00	#FFC700
3	0.80, 1.00, 0.00	#CCFF00
4	0.41, 1.00, 0.00	#69FF00
5	0.01, 1.00, 0.00	#03FF00
6	0.00, 1.00, 0.40	#00FF66
7	0.00, 1.00, 0.79	#00FFC9
8	0.00, 0.80, 1.00	#00CCFF
9	0.00, 0.41, 1.00	#0069FF
10	0.00, 0.00, 1.00	#0000FF

Algorithm (replicate exactly):

ratio = 100 / (maxPressureAlt - minPressureAlt)
for each fix i>0:
  pct  = clamp(ratio * (fix.pressureAlt - minPressureAlt), 0, 100)   // non-finite -> 0
  step = round(pct * 2.0)                                           // 0..200, 0.5 % buckets
  segment prev->fix takes the step of the END fix
  consecutive equal steps merge into one LineString; a new run starts with the previous fix (continuity)
  runs need >= 2 coords
  feature.properties.color = ramp.color(step / 2.0)
ramp.color(pct): p = clamp(pct,0,100)/100; x = p * (count-1); lerp RGBA between floor(x) and ceil(x)

Encoded as rgba(r,g,b,a) strings (sRGB 0–255 clamped) — MapCompatShapes.swift:283-317.

3.3 Simplification

• Map: no client-side Douglas–Peucker; relies on GeoJSON source tolerance (default 0.375 for all track sources, 0.0 for coloredFlight). No per-zoom logic. Android: same tolerance option on geoJsonSource.
• Packages/TrackShape is only for thumbnails (list rows, widget, detail popup), not Mapbox. TrackSimplifier.simplify(coords, maxPointCount = 200): project to Web Mercator, normalise per-axis to unit square (zero-extent axis → 0.5), iterative Douglas–Peucker ranking (endpoints ∞, child rank clamped to parent), drop rank ≤ 0.001, keep top-N by rank, re-sort by index; perpendicular distance to the clamped segment. SimplifiedTrack.encodedData(): [version u8 = 1][aspect f32 LE][x,y f32 LE…] (persisted — keep the byte format if thumbnails sync). TrackShapeView: line 1.6, inset 8, round cap/join, start dot r = 1.6×lineWidth, aspect clamped [2/3, 1.5]. Task outline: closed loop, max 32 pts. Android: port to a pure Kotlin module + Compose Canvas.

3.4 Thermals on the map

• Layer thermals.fill (ThermalFillStyleLayer.swift): FillLayer, minzoom 8, fill-color ["get","fillColor"], fill-opacity 0.4, no outline.
• Geometry: circle around thermal.centerCoordinate, radius totalRadius (encloses all circling fixes), 0…360° in 5° steps (73 pts), spherical R = 6 371 000 m.
• Colour: vario < 0 → Thermal Sink #F61D24; else lerp [Thermal Bad #F6B91E, Thermal Good #98F61E] at 100 * vario / maxVario.
• Properties: fillColor, id (UUID string), isAttempt (altitudeGained ≤ 0).
• Filter: thermals+attempts → none; attempts only ["==",["get","isAttempt"],true]; thermals only ["==",["get","isAttempt"],false]; both off → source data nil. Prefs VultureShowThermals, VultureShowThermalAttempts (default off).
• Tap → thermal sheet (Pro) + scrubber jumps to thermal centre fix.

No glide/phase colouring on the map — phases only in the barogram.

3.5 Events (takeoff, release, landing, low/high, furthest, IGC events)

No dedicated start/finish icons. Points for all fixesWithEvents, property name:

• events.layer CircleLayer: minzoom 9, circle-color #FFFFFF, circle-stroke-color #5F5F5F, circle-radius and circle-stroke-width both interpolate linear zoom 9 → 1.6, 14 → 3.0.
• events.labels SymbolLayer: minzoom 9, text-field ["get","name"], text-size 12, text-translate [8,0], text-justify left, text-anchor left, text-opacity interpolate linear zoom 7 → 0, 8 → 1, colour = waypoint label colour (secondaryLabel; light-resolved on outdoor/streets, white on satellite).
• Event names: VultureTakeoff, VultureRelease, VultureLanding, VultureAltitudeGainLowPoint, VultureAltitudeGainHighPoint, VultureFurthestPointFromHome + IGC events (localised for display).

3.6 Glider marker during replay (Map/Rendering/Views/GliderAnnotationView.swift)

Aspect	Value
Host	v11 ViewAnnotation, annotatedFeature = .geometry(Point), allowOverlap = true; updated by reassigning the geometry
Image	Template PDF by sport: Glider 40×19 pt (scale 1.0); Parapente 41×15 × 0.7; Delta 40×15 × 0.7. Flight’s detected sport overrides pref VultureAnnotationStyle
Tint	label colour, resolved light (black) on outdoor/streets, white on satellite, dynamic otherwise
Rotation	radians(fix.bearing − map.bearing), no animation; re-applied on camera change only if bearing changed
Label pill	Registration, caption1, insets 2/6/2/6, corner = h/2, 10 pt above image, centred
Selected	image alpha 1.0; pill bg = flight colour, text = inverse colour; brought to front
Unselected	image alpha 0.5; pill bg clear, text = flight colour
Inverse colour	brightness=(r*299+g*587+b*114)/1000; < 0.6 → systemGray6, else label
Lifetime	Exists only while the flight has a fix at the current time
Tap	light impact haptic, select flight

Android: ViewAnnotationManager + AndroidView/Compose ViewAnnotation works for ≤ ~10 gliders. For competition days (30–50 flights) prefer a SymbolLayer with icon-rotate ["get","bearing"], icon-rotation-alignment map, icon-image SDF glider (tinted via icon-color), and a text pill — fed by one GeoJSON source updated per tick. This also matches the 3D plan (ModelLayer later). Decide early; a mixed approach (symbols for others, view annotation for selected) is acceptable.

3.7 Task / turnpoint / observation-zone drawing

Flight map (FlightMapViewDataSource+Layers.swift:79-97), source task:

Layer	Style
task.border.dashed	round; width interpolate linear zoom 8 → 1.6, 14 → 3.0; dash [1,2]; line-color ["get","lineColorKey"]
task.fill	minzoom 6; fill-color ["get","fillColor"]; fill-opacity 0.2
task.border	minzoom 6; round; line-color ["get","borderColor"]; line-opacity 0.8; width 9 → 1.5, 14 → 3.0

Task map adds task.layer (solid, width 2.0 constant), taskMetadata.labels (text-field ["get","text"], colour #5C7EA1, size 14, text-rotate ["get","rotation"], rotation-alignment map, anchor bottom, line-height 2.3, allow overlap) and taskMetadata.layer (icon-image ["get","icon"] = direction, icon-rotate ["get","iconRotation"], icon-color #5C7EA1, allow overlap).

Features (Map/Extensions/Task+Features.swift, Task/Task+Feature.swift, Waypoint/Waypoint+Features.swift). Property keys: literal "lineColorKey", "fillColor", "borderColor".

• Leg line: turnpoints with a great-circle midpoint inserted before each point; lineColorKey = #5C7EA1, fill/border clear.
• Leg label (task map): midpoint point; text = distance 0 decimals + " FAI" if count == 4 && leg/total >= 0.28; rotation = (bearing>180 ? bearing-180 : bearing) - 90; iconRotation = bearing.
• Zone with 2 coords (line) → LineString, border #ED5656, others clear.
• Zone polygon → fill #D5A359, border #ED5656 if showBorder (task map) else clear (flight map).

Zone geometry (fields R1, A1, R2, A2, A12, isLine, type; metres/degrees) — Packages/Map/.../CLLocationCoordinate2D+ObservationZone.swift, already tested in WaypointsTests (port those tests):

Case	Geometry
isLine	2 points at R1 on bearing ± 90°
A1>0, A2>0, R2>0, A1 ≥ 180	circle R1
…, A2 ≥ 180 (keyhole)	arc R2 end → start (start = bearing − A1, end = start + 2·A1), repeat last, arc R1 start → end, close
…, else	sector arc at R2: bearing − A2 … + 2·A2
simple, A1 ≥ 180	cylinder R1
simple, else	[centre] + arc(R1, bearing − A1 → +2·A1) + [centre]

Arc sampling: count = ceil(range/5), step = range/count; from == to → 360°; to < from → +360. Spherical destination with R = 6 371 000 m. Bisector bearing (points away from the course): fixed with A12>0 → A12+180; next → bearing(next→wp); previous → bearing(prev→wp); start → bearing(start→wp); symmetric with both neighbours: bp,bn = Int bearings wp→prev/next, mid = (max−min)/2 + min, result mid if max−min ≥ 180 else mid−180.

3.8 Multi-flight comparison

Aspect	Behaviour
Palette	20 colours Flight 1…20 (DesignSystem, display-p3, no dark variant): #4A6FA0 #5B5B99 #6E528F #884C89 #9C4880 #A64F66 #A65252 #AA6548 #AA7648 #AA8842 #AA9842 #A2A148 #88A14C #689A50 #50935E #469378 #46938A #469393 #46869E #467A9E
Assignment	Round-robin shared index 0…19 (FlightMapViewModel.swift:603-610); if all flights have a competition rank → re-sort by rank and recolour all[i % 20]
Primary	First added (or selecting) when none selected; tap glider / panel card re-selects
Selected-only overlays	thick/coloured track, task, optimisation, events, thermals, photos, graph extras
Others	thin .line in their colour + glider at 0.5 alpha
Labels	glider pill with registration
Time sync	Each flight has timeOffset (s). Default 0 = real time of day. “Align task start times”: offset = earliestTaskStart − thisTaskStart (best task attempt first fix). Readout becomes T+hh:mm:ss. Other flights at time t: fix(for: t − offset) binary search → exact or next later fix; nil outside range
Gate	>1 flight = Pro (ProFeature.severalFlights)
Downloads	Soaring Spot / Charron: 3 concurrent, day task applied

3.9 Highlight (task leg / infringement)

Source highlight, layers highlight.layer (.highlight or .infrigement) then highlight.border added on top — note the wider darker border ends up above the line (looks unintended; on Android put the border below unless pixel parity is required). Infringement uses MultiLineString. Camera fits the highlight afterwards.

3.10 Photos

Clustered GeoJSON (clusterRadius 35), photos.fill circle + photos.layer icon (photo / photos) + photos.labels (count). Tap opens the photo pager. Android equivalent: geoJsonSource { cluster(true); clusterRadius(35) } with point_count expressions.

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4. Barogram

4.1 Implementation

Custom UIKit + CoreGraphics, no chart library (no Swift Charts/DGCharts). Paths built off-main, rasterised into bitmaps covering only the visible window; axes/handle/badges via CAShapeLayer/CATextLayer.

Type	File (Map/Flight/Panel/…)	Role
PanelContentViewController (+Layout/+Graph/+Playback)	Panel/	panel content: dragger, flights row, graph, controls
PanelGraphViewController	Panel/Graph/	binds view model streams
PanelGraphView (+Gestures, +Accessibility)	Panel/Graph/	Y-axis, horizontal UIScrollView (zoom), handle, one data view per flight
GraphDataSource	Panel/Graph/GraphDataSource.swift	ranges, intervals, unit conversion, time↔progress, fix lookup, offsets
GraphFlightDataView	Panel/Graph/Views/	per-flight paths, dots, badges, AAT, pills
GraphBitmapRenderer	Panel/Graph/Views/	rasterises 3 bitmaps: under, over, highlight
GraphMetadataView		Y grid + labels
GraphHandleView, GraphHandleMetadataView, GraphValueView		scrubber, dot, readout bubble

X domain: progress 0…100 over [min startRecordingTime, max endRecordingTime] of all loaded flights (GraphDataSource.swift:406-410, 515-522).

4.2 Main series (one at a time)

GraphDataUnit (Packages/Preferences/.../GraphDataUnit.swift), persisted Defaults[.graphDataUnit], default pressureAltitude: pressureAltitude, gpsAltitude, groundspeed, vario, windSpeed, averageSpeed, averageTaskSpeed, totalEnergy, trueAirspeed, outsideAirTemperature, gForce, verticalAcceleration, verticalAirMovement, attitudeRollAngle, attitudePitchAngle, electricalVolts, electricalCurrent, fuelLevel, fuelFlow, temperatureExhaustGas, temperatureMotor, temperatureController, temperatureJetPipe, batteryLeft, flapPosition, engineRPM, meansOfPropulsionLevel, heartRate, bloodOxygenLevel.

Menu (FlightMapViewModel+GraphMenu.swift:40-73): inline [averageTaskSpeed (if task attempted), averageSpeed]; [windSpeed, vario, groundspeed]; an “Altitude” group [extension extras e.g. totalEnergy…, gpsAltitude, pressureAltitude]; one group per IGC-extension category present. The groups are titled and inline, not submenus (UIMenu(title:options: .displayInline), since 4b24851f4, 2026-10-16; Android the same since build 4). GPS altitude skips 2D fixes; wind uses last sample ≤ t. Pressure altitude with terrain shows readout as AGL "%0.f %@ AGL".

4.3 Layers drawn per flight

Series	Condition	Colour	Style	Bitmap
Main trace, selected	always	flight colour	stroke 2.0, α 1.0	over (top)
Main trace, unselected	always	secondaryLabel	stroke 1.0, α 0.3	over
Terrain (ground elevation)	selected, elevation available, altitude unit	fill #C3AC93 / dark #644E35; stroke #AD8F6C / dark #8A6C49	closed polygon to bottom, line 1.0	over (first)
No-terrain baseline	elevation nil	#AD8F6C/#8A6C49	1 pt line at bottom
GPS altitude backdrop	selected, !showAltitudeGained	tertiaryLabel	fill α 0.3	over
Thermals	selected, VultureShowThermals	#69AB8B	full-height rect entry→exit, α 0.3	under
Thermal attempts	selected, VultureShowThermalAttempts	#FF4139	full-height rect, α 0.3	under
Engine (ENL/MOP)	selected	#F6B91E	filled curve, α 0.3	under
Highlight (leg/infringement)	selected, highlight set	leg #D5A359 / infringement #ED5656	stroke 2.5	highlight (top)

Engine curve: drawn where fix.engineLevel > 200 + flight.engineLevelThreshold (else at bottom), y = h − engineLevel/1000 · h — absolute 0–1000 scale independent of the Y axis. engineLevel = max(ENL, MOP); engineLevelThreshold = 200 + ΣENL / fixCount (so effective threshold = 400 + mean ENL).

Terrain source: not Mapbox — SRTM 3″ .hgt tiles (1201×1201 Int16, name like N50E005) from https://vulture.aero/api/elevations/<tile> (Authorization header; token in Packages/Flights/.../ElevationServiceConfiguration.swift), cached Caches/elevations/<tile>.hgt, 10 s timeout; nearest-sample lookup (row = Int(frac(-lat)·1201), col = Int(frac(lon)·1201)), stored per fix as fix.elevation; flight.isElevationAvailable.

Point markers (selected, only when altitude unit and pref showAltitudeGained): circle r 6, stroke 2, fill same colour α 0.2 — Lowest #F61D24, Highest #4C9172, Release systemGray, PEV #D5A359, Furthest #5C7EA1. Event pills (white caption2 text, capsule height 16, width 12+text+8, with an even-odd hole r 6 at the dot) fade in 0.2 s when the handle/hover x is within 10 pt; flip left if overflowing or overlapping the readout.

Task badges above the plot (36 pt top inset): DotTextLayer circles “S”, “1…n”, “F” (completed) / “X”; size = caption2 + 4; task-attempt badges + dashed vertical lines #519672 width 1.5 dash [3,4]; distance-optimisation badges/lines #DF774A width 1.5 dash [4,3]; lines sit below the over bitmap. AAT minimum time: horizontal line at y=0 from task start for the duration, #D5A359 width 2, label "AAT: 1h30m" caption2. Prefs: showTask && showOptimizedTask, showTrack, showTask && showAssignedTaskTime.

No airspace vertical profile in the graph (only the red infringement highlight stroke). No glide shading (unshaded = glide).

4.4 Axes

• Y axis column 54 pt (label 50 + gap 4); labels "\(value) \(unit)" caption2, right-aligned, secondaryLabel; grid lines tertiaryLabel 1 pt full width; label thinning stride 1,2,4… until spacing ≥ 22 pt counted from the bottom (grid lines stay).
• Mapping: yRatio = h / (max − min + valueOffset), y = h − (v − min)·yRatio − valueOffset·yRatio; valueOffset = −rawMin only for altitude when raw min < 0.
• Interval tables (GraphDataSource.swift:624-709), small (phone landscape) / large: altitude 1000 m / 3000 ft vs 500 m / 1500 ft; speeds 100 / 50; vario/TE 10 / 5; wind 20 / 10; OAT 20/10; g 2/1; flaps 1/1; RPM/MOP 1000/500; HR 10/40; SpO2 5/20 (some pairs look inverted, see §9). Density: range/interval > 14 → ×4; > 10 → ×2.
• Altitude with terrain & min>0: if min < interval → interval 100; min = minV − minV % interval, max = maxV + (interval − maxV % interval); recheck >14 → ((range/7 + 99)/100)·100, >10 → ×2. Without terrain: min = max(0, …).
• Other units: min = minV − (interval + minV % interval), max as above. Clamps: vario [max(−10,floor min), min(14, ceil max)]; TE min ≤ −5; speeds ≥ 0; battery ≤ 99; HR 0–200; SpO2 0–100.
• Readout formats: "%0.f %@" altitude/speed/wind, "%0.2f %@" vario/TE, "%0.1f %@" g, "%0.f °%@" temperature.
• No X/time axis is drawn. Time only in the readout: local takeoff-timezone HH:mm:ss, or T+hh:mm:ss when task-aligned.

4.5 Gestures, scrubber, haptics

Item	Value
Zoom	horizontal only, scale 1.0…10.0; content width = width·scale − 16; pinch anchored at finger; wheel scale *= 1 + dy·0.01
Pan	native scroll when zoomed, no indicator
Reset zoom button	visible when scale ≠ 1, fades 0.15 s
Handle	full-height line #DF774A 2 pt; tap jumps; 1-finger pan drags; when zoomed a pan only grabs the handle if it starts within ±40 pt (80 pt hit rect), else scrolls
Clamp	<0 → 1; > width → width−1 and emits reachedEnd (pauses playback)
Readout	dot r 6 #DF774A on the selected trace; bubble bg #DF774A, radius 8, padding 4, title footnote white, subtitle caption2 white α 0.8; top 4, at x+8 or flipped to x−8
Haptics	selection tick whenever the handle moves > 5 progress units (5 % of timeline)
Keyboard	Ctrl+←/→ = 2 pt; ←/→ = ±1 s flight time; Space = play/pause
Panel drag	disabled while the handle is active

Performance model: one sample per point of content width (for x in 0..<width: progress → fix by exact key or binary search), Y truncated to Int; paths rebuilt off-main with a generation counter; during pinch only an X-scale transform of existing paths, full rebuild at gesture end; bitmap window = viewport ±0.5 viewport width (or whole content if ≤ 2× viewport), re-render when the viewport leaves the window inset by 0.25 width; first appearance fade 0.35 s. Accessibility audio-graph resamples to 60 points.

4.6 Sync with the map

Graph → map: handle progress → [flight: fix] for every flight (with offsets) + time → FlightMapViewModel.updatePositions → move all gliders, pinned-follow check, satellite cloud frame update. Camera never follows a scrub otherwise.

Map/app → graph: timeSubject → positionHandle(time) (hidden when out of range). goTo(fix, shouldCenter) is called from: detail popup “centre fix”, thermal tap/selection (thermal centre fix), thermal-detail scrub, next/previous/nearest thermal, phase pill. Task legs/infringements → highlight(fixes:) on both graph and map.

Tapping the track line on the map does NOT move the scrubber (only thermals/photos are hit-tested). Android may add this as an enhancement but it is not parity.

4.7 Playback

Display-link driven (Android: withFrameNanos loop / Choreographer): acc += realElapsed · multiplier; consume whole seconds → go(to: t + n); pause at endRecordingTime, on background, on handle reaching end. Speeds ×10, ×25 (default), ×50, ×100, ×200 (Defaults[.playSpeed]). Play button: stopped “Play” play.circle, tap opens speed menu with subtitles “Duration: %d min %02d sec” (= flight duration / multiplier); playing “Stop (25x)” stop.circle, tap pauses, menu changes speed live.

4.8 Panel

Custom floating glass panel (FlightMapView.swift, Support/Views/FloatingPanel.swift): margin 8 from window edges, corner radius container-concentric min 16; height = 40 % of map height (45 % in compact vertical / phone landscape); states .all (0) and .none (2) persisted Defaults[.panelState]; spring 0.5 s damping 0.7 velocity 0.4; release decides by |velocity| > 500 else midpoint; round “show panel” button when hidden. Content: dragger (+3), flights row (h 70; 35 phone landscape; 30 with one flight, no scroll), graph container (inset 8, top corners 16, overlaps controls by 8), control row h 34 (play, reset zoom icon arrow.down.right.and.arrow.up.left, unit picker ≤ 50 % width); control row hidden in compact height. Graph insets: top 36 (badges), bottom 16, leading/trailing 8 + 54 pt label column. Every card over the map takes its side insets from FloatingPanel.insets(in:).

Android: BottomSheetScaffold is a poor fit (it is not a floating card with margins). Use a custom Box + AnchoredDraggableState with two anchors (shown/hidden), Material 3 Expressive surface (surfaceContainer with tonal elevation, 16–28 dp shape). Feed its height into map padding.

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5. Airspace

5.1 Sources

Source	Details	Where
OpenAIP vector tiles (default; forced without Pro)	https://api.tiles.openaip.net/api/data/openaip/{z}/{x}/{y}.pbf?apiKey=<KEY>, source minzoom 5, maxzoom 14, source-layer airspaces. API key hard-coded inline (Map/MapViewDataSource+Airspace.swift:240-242)	online only
User files (Pro “Custom Airspace”)	OpenAir .txt, OpenAIP XML .aip, SeeYou .cub; imported from Files or downloaded from catalogue	Core Data File
Catalogue	https://vulture.aero/api/ + xcsoar/airspace, xcsoar/waypoints, legacy openaip/airspace; JSON {"records":[{name, uri, type, area?, update "yyyy-MM-dd"}]}; Authorization JWT (location Packages/Backend/.../VultureServiceConfiguration.swift:41-47)	Packages/RemoteContent
File download	plain GET of record.uri, no auth	FileDownloadManager.swift
Updates	checkUpdates() at app start: refetch catalogue, flag .xcsoar files where record.update > file.contentUpdatedAt (match by name); auto re-download if VultureAutomaticUpdateEnabled, else prompt	FileDownloadManager.swift:94-208

Which one shows: showsOpenAIP = VultureOpenAIPAirspaceEnabled || !Pro(customAirspace). Only one set is drawn at a time; file geometry is held but not pushed while hidden.

Persistence (File entity): version, importedAt, filename, type (0 waypoints, 1 airspace), itemCount, content (text; CUB as Base64), isVisible, source (0 user, 1 xcsoar, 2 openaip), contentUpdatedAt, contentArea. Parsed data is not cached: every visible file is re-parsed on launch/change in background operations; renders coalesced 50 ms.

OpenAIP tile features become domain objects via a rendered-feature query of openAIPAirspace.fill.tap on every map idle (only if bounds changed) → merged into visibleAirspaces (dedupe by id, file wins) → feeds infringement detection.

5.2 Parsers (Packages/Airspace)

Encoding fallbacks: utf8, ascii, isoLatin1, isoLatin2, macOSRoman. Detection: extension (txt/aip/cub) or content (<OPENAIP in first 4096 chars; a line starting AC ; Base64 bytes 1..<4 == CUB).

OpenAir (Decoder/AirspaceOpenAirDecoder.swift): split on LF/CR, trim, skip empty and * comments; command = text before first whitespace.

Cmd	Handling
AC	finish previous; new airspace; reset arc centre nil, direction clockwise
AN / AL / AH	name / floor / ceiling
DP	add point
V X= / V D=	arc centre / direction (+ cw, - ccw)
DA r,a1,a2	arc radius NM, a1→a2 in current direction
DB c1,c2	arc around X, radius = average of both distances
DC r	full circle NM
AF / AX	frequency / transponder
AY AT SP SB TC TO AG AA	ignored

Coordinates: DD:MM:SS N, DD:MM.MMM, decimal; flexible whitespace/case. Arcs sampled every ~5° (ceil(range/5)), R = 6 371 000 m. Valid only with name+floor+ceiling; ring closed. Frequency = AF else regex 1\d{2}\.\d{1,3} in name.

Class (AC): A,B,C,E,F,G → same; D and Q → D; RESTRICTED/R → restricted; DANGER → danger; PROHIBITED/P/GAW → prohibited; CTR; TMA; WAVE/W → waveWindow; GLIDING/GSEC → gliding; TMZ; RMZ; FIR; else nil.

Altitude (AL/AH), in order: lowercase, strip msl; unl/unlimited → unlimited; exact gnd/sfc → ground; extract integer (none → invalid); contains fl → FL(n); contains m → metres else feet; contains agl → AGL else AMSL.

OpenAIP XML: AIRSPACES/ASP@CATEGORY (A–G, RESTRICTED, DANGER, PROHIBITED, CTR, TMA, WAVE, GLIDING, TMZ, RMZ, FIR, UIR→FIR), NAME, ALTLIMIT_BOTTOM/TOP@REFERENCE + ALT@UNIT (M = metres else ft; STD → FL; GND 0 → ground; GND → AGL; MSL → AMSL), GEOMETRY/POLYGON "lon lat, …".

CUB binary: little-endian header (ident 0x425543C2, title 112 B, …, sizeOfItem, sizeOfPoint, hdrItems, maxPoints, bounds f32, loLaScale f32, headerOffset, dataOffset, alignment); items ≤42 B (bounds f32, style u8 → class (b&0x70)>>4, cubStyle (b&0x0F)|((b&0x80)>>3); altStyle u8 low=min high=max: 0 unknown,1 agl,2 msl,3 fl,4 unl,5 notam; minAlt/maxAlt i16 metres; pointOffset i32 …); points (flag u8, x i16, y i16): 0x81 move origin by (x,y)·scale, 0x01 add point at origin+(x,y)·scale (radians→degrees), 0x40 name (len = flag&0x3F) optionally followed by frequency (flag&0xC0==0xC0, u32). Altitudes metres → ft rounded to 10; AGL 0 → ground; FL = ft/100. Full details: Packages/Airspace/.../Decoder/AirspaceCUBDecoder.swift, Models/CUB/*.

OpenAIP tile attributes: name (required), type, icao_class, lower_/upper_limit_value|unit|reference_datum, source_id. Class: icao_class a–g wins; else type: ctr→CTR; tma/cta/atz/lta/awy→TMA; restricted/tra/tsa→restricted; danger; prohibited; rmz; tmz; gliding_sector/aerial_sporting_recreational→gliding; fir/fis_sector→FIR. Altitude: unit FL or datum STD → FL; datum GND → ground if 0 else AGL ft; else AMSL ft; missing floor → ground, missing ceiling → unlimited. Id = djb2-style hash of source_id ?? name.

5.3 Model

Airspace { id: UInt64, name, class: Class?, floor, ceiling: Altitude, coordinates (closed ring), radioFrequency?, transponderCode?, openAIPSourceId? }.

• File id: uniqueHash(name + class.rawValue + filename + coords "lon:lat" joined "-"), hash h = 5381; for byte in utf8: h = 127 * (h & 0x00ffffffffffffff) + byte (UInt64 wrapping). Persisted (hidden sectors) — must match byte-exactly incl. Swift Double.description formatting of coordinates (Kotlin Double.toString differs for some values → write a Swift-compatible formatter + golden tests).
• Class raw: a “A” … g “G”, restricted “R”, danger “Q”, prohibited “P”, gliderProhibited “GP”, ctr “CTR”, tma “TMA”, waveWindow “W”, gliding “GLIDING”, TMZ, RMZ, FIR.
• Altitude: ground | agl(len) | amsl(len) | fl(Int) | unlimited. Ordering by feet (FL×100, unlimited ∞), AGL ranks higher on ties. valueInMeters: ground 0; FL Int(level·100 / 3.2808399); unlimited Int.max.
• Display: “Ground”, ”%@ AGL”, ”%@ AMSL”, “FL %d”, “UNL”; class labels “Class A”… “CTR”, “TMA”, “Restricted”, “Danger”, “Prohibited”, “Glider prohibited”, “Wave window”, “Gliding”, “TMZ”, “RMZ”, “FIR”, “Unknown”.

5.4 Settings / filtering

There is no class filter and no altitude-ceiling filter. Settings has two toggles:

UI	Key	Default
“Custom Airspace” (inverse of OpenAIP)	VultureOpenAIPAirspaceEnabled	false (but OpenAIP forced without Pro)
“Show hidden sectors”	VultureShowHiddenAirspaces	false

Per-sector hiding (file airspaces only): JSON in Documents <yyyyMMdd>-hidden-airspace.cache, [{"id":UInt64,"type":"permanent"|"today"}] (legacy [UInt64] = permanent); old day files deleted carrying permanent entries forward; “today” expires on date change (checked on scene activation). Hidden airspaces are filtered before render; tap lookup of hidden ones by point-in-polygon. Screens: hidden list (Packages/AirspaceScreens/.../HiddenAirspaces), per-file sectors with search (name or class raw).

5.5 Styling

Palette (Packages/Theme, single appearance): Blue #5C7EA1 (p3), Red #ED5656, Green #4C9172, Gray #5F5F5F, Light Gray #A9A9A9, Highlight #D5A359 (p3), Infringement #ED5656.

Per class (Packages/Theme/.../UIColor+Airspace.swift:44-93, Airspace.Class+Borders.swift, Airspace+Crossing.swift):

Class	Fill	Border	Dashed	Inner	isRestricted
A	–	red	–	✓	✓
B, C	–	blue	–	✓	✓
D	–	blue	–	–	✓
E	–	green	✓	✓	–
F, G	–	green	–	✓	–
CTR	blue	blue	✓	–	✓
TMA	–	blue	–	–	✓
Restricted	red	red	–	✓	✓
Danger	–	red	✓	✓	✓
Prohibited, GliderProhibited	red	red	–	✓	✓
WaveWindow	–	blue	–	✓	✓
Gliding	–	green	✓	✓	✓
TMZ, RMZ	–	gray	✓	✓	✓
FIR	–	light gray	–	–	–
nil	blue	red	✓	–	–

File-airspace layers (source airspace; feature props id (decimal string), borderColor, fillColor, hasDashedBorder, hasInnerBorder; GeoJSON feature id = id & 0x1F_FFFF_FFFF_FFFF for feature-state):

Layer	Paint	Filter
airspace.fill	fill-color = case(feature-state highlighted, #D5A359, get fillColor); fill-opacity = case(highlighted, 0.4, 0.1)	–
airspace.border.inner	width interpolate linear zoom 5→0, 6→4, 8→4, 9→10, 14→20; line-offset 5→0, 6→2, 8→2, 9→5, 14→10; colour get borderColor; opacity 0.1	hasInnerBorder == true
airspace.border.dashed	round; width 6→0, 7→1, 8→1, 9→2, 14→4; dash [4,3]	hasDashedBorder == true
airspace.border	same width, solid	hasDashedBorder == false

OpenAIP tile layers (source-layer airspaces). Border colour match(get type): restricted/tra/tsa/danger/prohibited → red; ctr/tma/cta/atz/lta/awy → blue; rmz/tmz → gray; gliding_sector/aerial_sporting_recreational → green; fir/fis_sector → light gray; default red. dashedTypes = ctr, danger, gliding_sector, aerial_sporting_recreational, rmz, tmz. innerBorderTypes = restricted, tra, tsa, danger, prohibited, gliding_sector, aerial_sporting_recreational, rmz, tmz.

Layer	Paint	Filter
openAIPAirspace.fill.tap	transparent, opacity 0.01 (hit target)	–
openAIPAirspace.fill	red, 0.1	type in [restricted, tra, tsa, prohibited]
openAIPAirspace.fill.blue	blue, 0.1	type == ctr
openAIPAirspace.border.inner	round; width 6→0, 7→2, 8→4, 9→6, 14→12; offset 6→0, 7→-1, 8→-2, 9→-3, 14→-6; opacity 0.1	innerBorderTypes
openAIPAirspace.border.dashed	round; width 6→0, 7→1, 8→1, 9→2, 14→4; dash [4,3]	dashedTypes
openAIPAirspace.border	same width, solid	not dashedTypes

(Inner-border ramp and offset sign differ between file and tile layers — keep as is.) No airspace labels on the map.

5.6 Selection, query, detail UI

• Query: long-press (tap while sheet open), right-click; layers openAIPAirspace.fill.tap or airspace.fill. Marker: 12 pt dot (label colour, 1.5 pt background stroke) with 40 pt pulse scaling 1→3, opacity 0.7→0, 1.5 s easeOut, repeat.
• Highlight: file → feature-state highlighted=true; OpenAIP → extra layers filtered name == <name>: airspace.highlight.fill (#D5A359, 0.4) and airspace.highlight.border (#D5A359, width 4, opacity 0.6). Centre: OpenAIP unions all visible tile features with the same name.
• Sheet (Map/Airspace/*, Features/Airspace/Airspace/AirspaceSheetViewController.swift, Packages/AirspaceScreens/.../AirspaceDetail/*): items = tapped + (hidden at point if pref) sorted by floor descending, initial selection = last (lowest). Fields: name (+ “XPDR code”), class label, floor, ceiling, frequency, swatch, hide (permanent / today) or show; Center action. Subtitle "<class> · <floor> – <ceiling>".
• Compact layout = vertical cross-section profile (AirspaceDetailProfileView/Layout): ordinal axis (one step per distinct limit), lane packing by interval partitioning, axis 92, lane spacing 8, min segment 26, insets 8/14, corner 8, border 2 (1.5 hidden), dash [4,3] if dashed/hidden, tint class colour 0.15, hidden α 0.55; glider altitude marker = dashed brand line + pill (hollow α 0.45 when outside), position badge “INSIDE” (red) or gap chips (”%@ below the floor”/”%@ above the ceiling”). Regular width: profile 55 % + AirspaceDetailCard (CEILING/FLOOR/FREQUENCY, Center, Hide menu). Accessibility sizes: list with swipe actions.
• Position logic: outside polygon → outside; floor < alt && ceiling > alt → inside; floor > alt → belowFloor(diff); else aboveCeiling(diff). Comparisons in each bound’s frame (AGL vs alt.agl, AMSL vs msl, FL vs fl). Flight-analysis altitude from the scrubbed fix: agl = pressureAlt − elevation, fl = Int(pressureAlt·3.2808399/100), msl = pressureAlt.
• Swatch AirspaceIndicator: circle 20 pt (16 in summary), fill 10 %, border 2 solid or dashed [4,3], optional 4 pt inner ring 10 % inset 2.

5.7 Infringement detection (recorded flight)

Map/Flight/Flight/FlightViewModel.swift:552-653, re-run on every visibleAirspaces emission, background queue:

1. Keep airspaces with class.isRestricted and floor.valueInMeters <= flight.maximumPressureAltitude; drop polygons < 2 coords; precompute bbox + floor/ceiling metres.
2. Iterate flight.phases; only .cruise(leg) and .thermal.
3. Candidates per phase: floor ≤ phase max alt and bbox intersects.
4. Per fix: floor <= pressureAlt && ceiling >= pressureAlt && pointInPolygon(coord) (planar even-odd ray cast, Packages/Flights/.../CLLocationCoordinate2D+Calculations.swift:12-29). Integer metres, no tolerance, AGL limits compared raw against pressure altitude (no terrain), FL via 3.2808399, unlimited Int.max.
5. Contiguous fix index ranges → [[Fix]] per airspace. AirspaceInfringement { airspace, fixes }, duration = Σ(last−first rawTime), single-fix group = 1 s.
6. With OpenAIP only on-screen airspace is known → footer “Infringements are shown for airspace visible on the map. Pan or zoom the map to check additional areas.”
7. UI: flight detail row “Airspace usage” (“Processing…” → “N Infringements”), list (indicator + class + clock duration; name caption), select → map highlight (MultiLineString #ED5656 + darker border) and graph highlight; actions “center infringements”, “clear”.

No along-track vertical airspace profile and no live in-flight warning exist.

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6. Other map data

6.1 Waypoints (Packages/Waypoints, Map/MapViewDataSource+Waypoints.swift)

CUP: split on -----Related Tasks-----; header normalised to name,code,country,lat,lon,elev,style,rwdir,rwlen,freq,desc (or prepended); lat DDMM.mmmN|S (≥9 chars), lon DDDMM.mmmE|W (≥10 chars); styles 0 unknown … 17 intersection (2 grass airfield, 3 outlanding, 4 gliding airfield, 5 solid airfield, …). Tasks: name + waypoint names, Options/ObsZone rows apply to previous task; takeoff/landing stripped. Waypoints from all files merged order-preserving unique.

Rendering (no clustering): circle <src>.layer minzoom 5, radius interpolate linear zoom 6→0, 7→r7, 8→r8; symbol <src>.labels minzoom 7, text-field get name, text-translate [8,0], left justify/anchor, text-opacity 8→0, 9→1.

Type	Circle	Text colour	Size	r7	r8
waypoint	#D5A359	secondaryLabel (light on outdoor/streets, white on satellite)	10	2	3
home	#DF774A	#DF774A	12	3	4
event	#5F5F5F	as waypoint	10	2	3

(Flight-map events use their own layers, §3.5.)

6.2 Airports

Bundled Packages/Airports/.../airports.json (4.8 MB, 47 991 entries; keys a name, b lat, c lon, d country, e ICAO, f [{s station, r MHz}], g elevation ft). Not drawn on the map — used for nearest airport within 3000 m (takeoff/landing naming), METAR, nearest list. Android: ship as asset, load lazily; consider a spatial index (grid) instead of linear scan.

6.3 Terrain

SRTM tiles from the Vulture API (§4.3) for barogram terrain and AGL. No Mapbox DEM.

6.4 Satellite cloud overlay (flight map, Pro)

FlightMapViewDataSource+Satellite.swift, Packages/Flights/.../Satellite/*. Tiles https://satellite.skysight.io/tiles/{z}/{x}/{y}@2x?date=<formatted>&mtg=true, 10-minute frames. One raster source per frame (tileSize 512, maxzoom 7), layer satellite.<unix>.layer with raster-opacity 0, raster-fade-duration 0, inserted below the lowest flight* layer. Sliding window: shown frame 0.5, ±2 neighbours 0.01 (keep decoded), others 0; cold jump keeps previous frame until map idle (timeout 1.0 s). Scrub → fix rawTime (UTC sec since midnight) + flight date → floor to 10 min. Tiles pre-downloaded and served from disk by an HTTP interceptor (also adds the SkySight Origin header). Android: HttpServiceFactory.setHttpServiceInterceptor (Mapbox common) or a custom HttpServiceInterface to serve cached tiles and add headers.

SkySight forecast overlays are task/in-flight map only (out of scope for this doc; see Docs/skysight-*).

6.5 Measure tool

Two-finger long-press: line measure (glider colour, width 3, round, opacity transition 0.35 s), end circles r 4, white stroke 2; distance label symbol with pill icon (icon-text-fit both, padding [4,12,4,12]), white text 13, rotated along line (text-rotation-alignment map). Shown/hidden via opacity only.

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7. Colour reference

Display-p3 values are given as p3 component×255; convert to sRGB for Android (Color(0.876f,0.467f,0.291f, colorSpace = ColorSpaces.DisplayP3) in Compose keeps them exact on wide-gamut screens; for Mapbox expressions convert to sRGB hex).

Token	Light	Dark	Space
Brand / Tint / AccentColor / Handle	#DF774A	same	p3
Success (task attempt)	#519672	same	p3
Baro Highlight / AAT / Task waypoint / Airspace Highlight	#D5A359	same	p3
Task leg / Turnpoint / Airspace Blue	#5C7EA1	same	p3
Task zone / Airspace Red / Infringement / Destructive	#ED5656	same	sRGB
Airspace Green	#4C9172	same	sRGB
Airspace Gray / Event	#5F5F5F	same	sRGB
Airspace Light Gray	#A9A9A9	same	sRGB
Elevation fill	#C3AC93	#644E35	sRGB
Elevation border	#AD8F6C	#8A6C49	sRGB
Engine / Thermal Bad	#F6B91E	same	sRGB
Thermal Good	#98F61E	same	sRGB
Thermal Sink / Low	#F61D24	same	sRGB
Baro Thermal	#69AB8B	same	p3
Baro Thermal Attempt	#FF4139	same	p3
Flight 1–20	see §3.8	same	p3
Baro lines / altitude backdrop	iOS tertiaryLabel → M3 outlineVariant
Baro labels / unselected trace	iOS secondaryLabel → M3 onSurfaceVariant
Field colours (Theme Color.*Field)	blue #32769E, yellow #EBAC57, red #ED5656, green #0B8E65, magenta #B052C8

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8. Android mapping

8.1 SDK and Compose

• Mapbox Maps SDK for Android v11 (com.mapbox.maps:android:11.x + com.mapbox.extension:maps-compose:11.x), pin an exact version in the version catalog (same “never float” rule). Pick the 11.x matching iOS 11.32 if available, else latest 11.x at start.
• Compose: MapboxMap(modifier, mapViewportState, style = { MapStyle(styleUri) }, compass/scaleBar/logo/attribution = {}). For the volume of custom layers and frequent updates, use MapEffect(Unit) { mapView -> … } and drive layers imperatively through mapView.mapboxMap.style with the Style DSL (com.mapbox.maps.extension.style.*). The declarative Compose layer API (LineLayer(sourceState = …)) is fine for static layers but costs recomposition per update; keep high-frequency things (glider positions, satellite opacity) imperative.
• Keep the iOS layering: Compose screens/ViewModels are Mapbox-free; a FlightMapController (Android analogue of MapViewDataSource) owns the MapView, sources, layers, annotations.

8.2 Layer/expression equivalents

iOS (v11 Swift)	Android (v11 Kotlin DSL)
LineLayer(id:source:) + lineWidth = .expression(interpolate linear zoom 9 a 14 b)	lineLayer(id, src) { lineWidth(interpolate { linear(); zoom(); stop { literal(9); literal(a) }; stop { literal(14); literal(b) } }) }
lineColor = Exp(.get){"color"}	lineColor(get("color"))
lineDasharray [1,2]	lineDasharray(listOf(1.0, 2.0))
FillLayer + feature-state highlight	fillColor(switchCase { boolean { featureState { literal("highlighted") }; literal(false) }; literal("#D5A359"); get("fillColor") }); mapboxMap.setFeatureState(sourceId, null, featureId, Value(mapOf("highlighted" to true)))
Filter ["==",["get","hasDashedBorder"],true]	filter(eq { get("hasDashedBorder"); literal(true) })
OpenAIP match on type	lineColor(match { get("type"); literal(listOf("restricted","tra",…)); color(red); …; color(red) })
Vector source	vectorSource("openAIPAirspace") { tiles(listOf(url)); minzoom(5); maxzoom(14) }, layers with sourceLayer("airspaces")
GeoJSON source options	geoJsonSource(id) { maxzoom(16); buffer(64); tolerance(0.0); lineMetrics(false); cluster(true); clusterRadius(35) }
Push shape	source.featureCollection(fc) (async in v11; throttle to 30 Hz as iOS)
RasterSource + rasterOpacity, rasterFadeDuration 0	rasterSource(id){ tiles(...); tileSize(512); maxzoom(7) }, rasterLayer(id, src){ rasterOpacity(0.0); rasterFadeDuration(0.0) }
setOpacity(of:identifier:) single-property	style.setStyleLayerProperty(layerId, "raster-opacity", Value(0.5))
addLayer(_, layerPosition: .below(id))	style.addLayerBelow(layer, belowId) / addLayerAbove / layerAtPosition
setProjection(globe)	style.setProjection(projection(ProjectionName.GLOBE))
Standard lightPreset import config	style.setStyleImportConfigProperty("basemap", "lightPreset", Value("night")); in Compose MapboxStandardStyle { lightPreset = LightPresetValue.NIGHT }
setImage(_:forName:)	style.addImage(name, bitmap, sdf = true) (SDF for tinted template images)
ViewAnnotation	ViewAnnotationManager.addViewAnnotation(view, viewAnnotationOptions { geometry(point); allowOverlap(true) }) or Compose ViewAnnotation(options) { … }
Async queryRenderedFeatures	mapboxMap.queryRenderedFeatures(RenderedQueryGeometry(screenBox), RenderedQueryOptions(layerIds, null)) { result -> }
camera(for: coords, padding:) + ease 0.3 s	mapboxMap.cameraForCoordinates(coords, CameraOptions.Builder().build(), EdgeInsets(...), null, null) { cam -> mapView.camera.easeTo(cam, mapAnimationOptions { duration(300) }) }
onStyleLoaded, onMapIdle, onCameraChanged	subscribeStyleLoaded, subscribeMapIdle, subscribeCameraChanged (debounce 200 ms with a coroutine debounce)
Pitch off	gestures.pitchEnabled = false
Hide logo/attribution	logo.enabled = false, attribution.enabled = false (attribution in About; check ToS)
Satellite tile cache + Origin header	HttpServiceFactory.setHttpServiceInterceptor(...) (common SDK)

Colours in expressions: Android Mapbox accepts "rgba(r,g,b,a)" strings and color(Int). Keep the per-segment altitude colour property as an rgba() string (or an int packed colour with toColor).

8.3 Track data shape for Android

• Per-segment altitude features (≤ 201 colour buckets, merged runs) exactly as iOS. Alternative line-gradient + line-progress (needs lineMetrics=true) would look smoother but differs visually from iOS and interpolates by distance not fix — keep segments for parity; add an altitude property per segment now so the 3D line-z-offset plan stays open.
• Build features on Dispatchers.Default; push on main.

8.4 Barogram recommendation: custom Compose Canvas

Recommend a custom Compose Canvas (with an android.graphics.Picture/ImageBitmap cache), not Vico or MPAndroidChart:

Criterion	Custom Canvas	Vico 2.x	MPAndroidChart
Parity with iOS visuals (terrain fill under trace, full-height thermal bands, engine curve on independent scale, badges above plot, AAT line, event pills with holes, multi-flight alpha)	exact	partial; decorations/markers possible but layered composition is fighting the lib	partial; View-based, dated styling
10k–50k points, 60 fps scrub	yes: pre-decimate to 1 sample per pixel column (as iOS), cache paths/bitmap, scrub draws only the handle layer	OK with own decimation, but its model re-measures on updates	decent but View/invalidate-based, no Compose
Horizontal-only zoom 1–10× anchored at pinch + pan + handle hit-rect arbitration	trivial with pointerInput/transformable	built-in zoom is both axes or custom; handle arbitration hard	built-in, but gesture arbitration with a draggable handle awkward
Two-way sync with map + playback at 60 Hz	state hoisted in ViewModel (progress: Float), handle in its own draw layer	marker API not designed for external driving	possible via highlightValue but heavy
Maintenance / dependency	none	active lib, API churn 1.x→2.x	unmaintained since ~2020

Implementation sketch:

1. BarogramModel (pure Kotlin, testable): port GraphDataSource ranges/interval tables/format strings and time↔progress mapping verbatim.
2. Path builder off-main (Dispatchers.Default): for each flight, sample widthPx·scale columns → FloatArray y-values; build Paths for trace, terrain, backdrop, thermals, attempts, engine, highlight. Cancel stale builds (coroutine collectLatest = iOS generation counter).
3. Draw: three cached layers (under, over, highlight) via Modifier.drawWithCache or recorded GraphicsLayer (Compose 1.7+ rememberGraphicsLayer), rendered only for the visible window ±0.5 viewport; during pinch apply scale(scaleX, 1f) transform to cached layers and rebuild on gesture end — same strategy as iOS.
4. Handle + readout + pills in a separate lightweight Canvas/composables on top so scrubbing never invalidates the data layers.
5. Haptics: HapticFeedbackType.SegmentFrequentTick (or TextHandleMove) every 5 progress units.
6. Accessibility: semantics with progressBarRangeInfo/custom actions to step ±1 s; content description of current readout.

8.5 Mapbox token on Android

• Public token (pk.…) goes in res/values/mapbox_access_token.xml as <string name="mapbox_access_token" translatable="false"> — generated at build time from local.properties / CI secret (MAPBOX_ACCESS_TOKEN) via a Gradle resValue, not committed. Or set MapboxOptions.accessToken = BuildConfig.MAPBOX_ACCESS_TOKEN in Application.onCreate before any map.
• Downloads token (sk.… with DOWNLOADS:READ) is needed only if pulling from Mapbox’s Maven repo with auth; store in ~/.gradle/gradle.properties (MAPBOX_DOWNLOADS_TOKEN) / CI secret, never in the repo.
• Restrict the public token by Android package name + signing cert SHA in the Mapbox account (iOS uses bundle ID restriction equivalently).
• Same treatment for the OpenAIP API key and the Vulture backend JWT: currently hard-coded in iOS source; on Android inject via BuildConfig from secrets and ideally move behind the backend.

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9. Quirks to replicate or fix deliberately

#	Quirk	Where
1	highlight.border (wider, darker) drawn above highlight.layer	FlightMapViewDataSource.swift:162-217
2	OpenAir AC Q → class D (not danger)	Airspace+Class.swift:43-45
3	AL 1000ft GND/SFC with a number parsed as AMSL (only “agl” detected)	Airspace+Altitude.swift:26-64
4	Infringement: AGL limits vs raw pressure altitude, no tolerance, only cruise/thermal phases	FlightViewModel.swift:569-639
5	Unlimited ceiling never reports “inside” in sheet	Support/Extensions/Airspace+Formatter.swift:17-30
6	OpenAIP tile AGL/AMSL always treated as feet	Airspace+Altitude.swift:86-100
7	Persisted airspace id hash depends on Swift Double string formatting	Airspace.swift:50, String+Hash.swift
8	Baro interval tables with inverted pairs (vario ft/s 500/1000, current 2/50)	GraphDataSource.swift:637-691
9	Baro valueOffset from raw (pre-conversion) min	GraphDataSource.swift:83-89
10	Baro markers’ Y always converted with altitude unit	GraphDataSource.swift:537
11	Haptic threshold in progress units, not px	PanelGraphView.swift:219
12	Dotted/task-dashed width stops start at zoom 8, solid at 9	FlightTrackLineStyleLayer.swift, LineStyleLayer.swift
13	Tapping the track on the map doesn’t scrub	FlightMapViewDataSource+Gestures.swift
14	Infringements with OpenAIP only cover airspace currently rendered on screen	queryOpenAIPAirspaces

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10. Risks and size estimate

Risks

• Glider markers at scale: View annotations are fine for a few flights; competition days (30–50) need a SymbolLayer approach — decide up front.
• Barogram performance & gesture arbitration (handle vs scroll vs sheet drag vs map) in Compose — the hardest UI piece; prototype first.
• Hash compatibility for hidden airspaces (only matters if data migrates/syncs between platforms; otherwise can use a new scheme).
• OpenAIP infringement coverage depends on rendered tiles — same limitation on Android; a better approach (fetch OpenAIP features via REST for the flight bbox) is a possible improvement.
• Secrets: OpenAIP key and backend JWT are hard-coded on iOS; Android needs a secrets plan.
• Display-p3 colours look slightly different unless converted properly.
• CUB binary parser and OpenAir edge cases need golden-file tests against iOS output.
• Mapbox ToS for hidden attribution.

Rough size (one experienced Android dev, incl. tests):

Area	Estimate
Mapbox setup, styles, light/dark/standard preset, camera/padding, gestures, measure	1.5–2 wk
Track layers, altitude colouring, events, thermals, photos clusters, task/OZ geometry (+tests)	2–2.5 wk
Gliders, multi-flight colours/time alignment, playback clock, pinned follow	1.5 wk
Barogram (custom Canvas, all series, axes, zoom/pan, handle, readout, badges, pills, perf)	3–4 wk
Floating panel + controls (unit menu, play/speed, reset zoom)	1 wk
Airspace parsers (OpenAir, OpenAIP XML, CUB) + model + tests	1.5–2 wk
Airspace rendering (file + OpenAIP tiles), query, highlight, hidden sectors, catalogue download/update	2 wk
Airspace sheet with cross-section profile + infringement detection & list	2 wk
Satellite cloud overlay with interceptor cache	1 wk
SRTM elevation service + enricher	0.5 wk
Total	~17–21 dev-weeks (≈ 9–11 k LOC Kotlin)