Aircraft readability on the map, v2: thin outline, sizes, a ring for persons of interest and 4 color groups (before/after)

[vmguessab]

Hi! This replaces #695, which I'm closing as outdated: I kept tuning the aircraft locally and the colors in #695 are no longer the ones I use. Same setup: ShadowBroker open all day as a half-screen "wallpaper" on a 4K TV (150 % scaling), SATELLITE style, VIIRS night lights on. Sharing the before/after in case it's useful. Happy to turn it into a PR, or into a display option, if you like it.

Tested on v0.9.84 (image of 24 Aug 2026). I checked current main (e6e8f6e, 6 Nov 2026): no commits since, so this still applies.

Each pair uses the same data at the same minute, the same window (1209 × 1343 CSS px at 150 %) and the same start view (zoom 5.7: my local setting, not part of the proposal).

Night: SATELLITE + VIIRS night lights

Day: SATELLITE

Close-ups (x2)

What changed

1. Four color groups for tracked aircraft instead of about 13 colors. On a busy map I could not tell that many hues apart, and several sat close to map elements: light grey borders and place names, cyan sea names, red GPS-jamming zones, white snow. Tracked aircraft now fall into four groups by alert_category (I do it client-side on tracked_flights; it could live wherever alert_color is assigned):

Group	Categories	Before	After
Persons of interest	People, Football, Don't you know who I am?, Dictator Alert, Da Comrade, Oligarch, Head of State, Royal Aircraft, and any other pink or red	hot pink #FF1493 / red	yellow #FEFB0A, white ring, name always shown
Military, state & security	military categories (yellow today), Governments, Government, Police Forces, State/Law, Quango, UK National Police Air Service, CAP	yellow / blue / navy	amber #FFB63A, same as the military layer
Rescue	lime categories (Flying Doctors, Coastguard, Aerial Firefighter…)	lime #32CD32	green #0DFD8F
Private & business	Bizjets, Business, Vanity Plate, PIA, Climate Crisis, As Seen on TV, Joe Cool, and the other orange, white, black or purple ones	pink / orange / white / black / purple	lilac #CEB1FB, same as the private layer

2. Other aircraft fills (map/icons/AircraftIcons.ts):

Layer	Before	After
Commercial (DimCyan)	#0891b2	#88B5FC
Private flights / jets	#9B59B6	#CEB1FB
Military (amber; fighter / tanker / recon yellow)	#f59e0b / yellow	#FFB63A
Grounded	#555	#6787A5

3. Outline: a thin dark outline (#29342C, 2 units) under each aircraft instead of the black stroke, so the icons keep their shape over city lights and snow. Persons of interest get a white ring; the POTUS fleet keeps its gold ring.
4. Names: in the group color; always shown for persons of interest, from zoom 6 for the other tracked aircraft (before: pink and red always, the others from zoom 5, yellow and black never).
5. Sizes and opacity at low zoom (MaplibreViewer.tsx): commercial icon-size 0.8 → 0.6 at zoom 5, and icon-opacity 0.75 at zoom 5 rising to 1 at zoom 8, so the tracked groups stand out; private, jets and military 0.8 / 1 / 2 → 0.9 / 1.1 / 2.2 at zoom 5 / 8 / 12.
6. Kept from Night readability on SATELLITE + VIIRS night lights: aircraft colors and layer opacity (before/after) #695: VIIRS night lights raster-opacity 0.9 → 0.55 with raster-brightness-min 0.08 and raster-brightness-max 0.88; reference overlay over imagery → 0.7.
7. Legend (KEY panel): the tracked section lists the four groups.

Contrast (APCA Lc, absolute) on the terrain around the aircraft, measured on the screenshots (night #36403c / day #425743):

Group	Before	After
Commercial	Lc 29 / 22	Lc 40 / 35 (at the layer's 0.81 opacity, zoom 5.7)
Private & business	Lc 21 / 14	Lc 59 / 52
Military, state & security	amber Lc 51 / 45, blue Lc 29 / 22	Lc 62 / 55
Rescue	Lc 52 / 45	Lc 78 / 71
Persons of interest	pink Lc 31 / 24	Lc 92 / 85
Grounded	Lc 0 / 0	Lc 27 / 21

Smallest color difference between the four groups: ΔE76 46 in normal vision, 24 in the worst of simulated deuteranopia and protanopia (Machado 2009).

Known trade-offs: the persons-of-interest yellow is the yellow of the "Threat Alert" news boxes (a text frame, so a different shape); with simulated color-vision deficiency the lilac gets close to the commercial blue, and the white ring fades on snow by day.

Now that there is a Display settings menu, this could also live there as a "high contrast" option instead of changing the defaults. Whichever you prefer.

[esmaeelE]

@vmguessab outstanding