Assets, Cache & Activity

H1. The Activity LED

When something is happening in the background, a small status dot appears in the bottom‑left corner of the map (when not in fullscreen). When everything is quiet, there's no dot at all — an invisible LED is the "all clear".

• Red, pulsing — something is downloading or processing. Tap it to see the message ("Downloading map assets…") in a small card, with a DISMISS button.
• Amber — something needs your attention. Tap it for the message and, where applicable, an action button. Today there is one such situation: a map download that failed ("Map download failed — check connectivity"), with a RETRY button beside it.

The LED is hidden in fullscreen along with the other overlays. If the orange FPS box (E4) is showing at the same time, it sits just above the LED rather than on top of it.

H2. Map downloads and updates

Sunline ships with a small base set of Earth textures sized to your device's class. The higher‑resolution tier used when you zoom is fetched automatically in the background after first launch; the optional content (seasonal months, the political timezone boundaries) is downloaded on demand.

How the assets are organised

Map textures come in five resolution tiers:

For each tier the app uses four base images:

• day.png — the daytime Earth (a single neutral texture when Show Seasonal Maps is off; otherwise one of twelve monthly textures matching the current month)
• nightlights.png — NASA Black Marble city‑lights overlay
• specular.png — water/ocean reflectivity map used to give the day side its glints
• cloud-demo.jpg — the bundled cloud composite used when Show Cloud Cover is on and live download is off or unavailable (clouds gain nothing from ultra‑high resolution, so this one tops out at the high4k tier and deeper zooms reuse it)

These are grouped into packs. The two you'll meet most often are:

• <tier>-required — the four base images at your device's tier. Installed once at first launch (the next tier up, used for zooming, follows in the background).
• <tier>-month-<month> — a single monthly texture (Premium); the seasonal map feature relies on these.

There are two small data packs alongside the maps:

• data-timezones-geographic — the 24 geographic timezone lines (free; tiny)
• data-timezones-political — the dissolved per‑offset political timezone outlines (Premium; a download well under a megabyte, fetched on demand)

You don't normally need to think about any of this — the app fetches what it needs in the background. If a download fails, the activity LED turns amber with a RETRY button.

If something ever seems stuck or broken with the downloaded maps, there is a last‑resort wipe in Settings → Advanced — see H3.

H3. Wiping the map cache (when all else fails)

In Settings → Advanced, under Storage & Cache, a Press here when all else fails button reveals the Wipe Map Cache button. It deletes every downloaded map asset and starts a fresh download from scratch — the base textures first, then the optional packs (seasonal months, political boundaries) your tier and licence call for. There's a confirmation dialog ("Wipe map cache?") before it runs, because the next few minutes will be spent re‑downloading; a small "Map cache wiped. Maps are being restored." message confirms it has started.

The wipe also throws away the cached daily cloud image and forgets when it was last fetched, so if you're Live with Download Daily Cloud Formations on, a fresh cloud composite is fetched straight away rather than waiting out the usual three‑hour interval (B5).

This is a recovery action, not routine maintenance: use it only if the maps seem stuck or broken and nothing else has helped. It won't reclaim meaningful disk space — the app re‑downloads the same assets it just deleted. It is available to everyone, free and Premium alike. Where there is no downloaded cache to wipe (the browser showcase, whose maps are bundled), pressing it just shows "Map cache wipe is unavailable on this platform."