Maps and Offline Use

Maps and offline use

The map

Roadstr draws OpenStreetMap with MapLibre Native: 3D tilt, rotation and native styling, in light and dark. The dark themes use the same OpenStreetMap tiles as the light ones, recoloured on the device (lightness inverted, hue rotated back). They do not come from a separate dark-tile service — CARTO's anonymous dark endpoint was used until 0.5.0, when it began serving an "API KEY REQUIRED" watermark instead of tiles without warning.

• Themes. Four: Light · Nostr Violet, Light · Bitcoin Orange, Dark · Nostr Violet, Dark · Bitcoin Orange (Settings → Theme). Auto dark theme (on by default) switches at local sunset and sunrise, computed from your GPS position with the NOAA solar-position algorithm.
• Map tile URL. Settings → Map lets you point the raster map at another tile server. The default is the OpenStreetMap standard layer (https://tile.openstreetmap.org/{z}/{x}/{y}.png).
• Attribution. Settings → Info → Maps opens the OpenStreetMap attribution.

Offline areas

Everything in this section is opt-in and explicit. Roadstr contacts the package host only after you open Offline areas (or start a download): there is no update check at launch, no prefetch and no background transfer.

Offline maps

Roadstr browses the live Geofabrik hierarchy, enriches it locally with GeoNames administrative areas and more than 34,000 cities, and downloads official Shortbread MBTiles extracts. Installed archives are drawn locally by MapLibre, without a network connection.

• Downloads are resumable: interrupted transfers keep a .part file and continue where they stopped.
• Every archive is verified (SHA-256) before it is installed, and installed atomically.
• Transfers are Wi-Fi only by default. You can allow a single transfer on mobile data after seeing its size and the free space; that choice does not turn on future automatic downloads.
• Closing the package panel cancels the stream; the partial file is kept for an explicit later resume.
• VersaTiles, OpenMapTiles and custom Roadstr HTTPS manifests are also listed as provider choices; regional VersaTiles builds and self-hosted OpenMapTiles catalogues can be imported through the advanced manifest flow.
• Package transport accepts only credential-free HTTPS, does not follow redirects and refuses addresses that resolve to non-public networks.
• Labels. Vector geometry draws offline immediately. Rich offline labels need a versioned glyph/sprite bundle in the package contract and are not advertised yet.

Offline routing

Routing packages run on the phone with the embedded Valhalla engine. It is an explicit, opt-in provider: nothing becomes offline-first unless you choose it.

• A request is served only if one installed package covers the whole of it; Roadstr does not stitch two neighbouring packages into one graph, because that would promise coverage that might not hold.
• Packages are checked by SHA-256 and by actually opening them in Valhalla before they count as installed.
• Public-transport routing is not available offline, by design — see Public transport.

Saved routes

A calculated route can be saved and reopened later without asking any routing provider: it starts from the stored geometry and instructions.

• Saved routes are stored encrypted with a dedicated Android Keystore key (up to 25 routes, 4 MiB in total), because destinations and travelled geometry are sensitive.
• Following a saved route's stored line works offline. If you leave it, recalculation needs a network or an installed offline routing package that covers the area; the app warns about that when you start a saved route.

Saved places, parking and favourites

• Settings → Saved Places lists, adds, edits and deletes favourites. Your parking spot is saved locally too.
• Export produces an encrypted JSON file (with an optional password); Import reads one back.
• Sync across devices through your Nostr relays is available once you are signed in — see Nostr and sign-in. Saved places and the parking spot never leave the phone unless you export or sync them.