alpimaps_data_generator

Builds the offline map data for AlpiMaps: vector basemap and route tiles, terrain-RGB elevation tiles, and a Valhalla routing package — for any area Geofabrik publishes.

The outputs are ordinary MBTiles and a Valhalla tar, so they work just as well with tileserver-gl, QGIS, MapLibre, or anything else that reads them.

What it produces

Output	What it is
${AREA}.mbtiles	OpenMapTiles-schema vector basemap, z0–14
${AREA}_routes.mbtiles	hiking and cycling route relations, kept in their own archive
${AREA}_terrain.mbtiles	terrain-RGB elevation, for shaded relief and 3D
valhalla_tiles.tar	routing graph, with elevation baked in

Requirements

Java 21+ and Rust. Then the native libraries the elevation and routing steps need:

# macOS
brew install aria2 gdal autoconf automake zmq czmq spatialite-tools luajit

# Ubuntu
sudo add-apt-repository ppa:ubuntugis/ubuntugis-unstable
sudo apt install -y aria2 gdal-bin autoconf automake pkg-config libtool make gcc g++ cmake \
  curl unzip jq protobuf-compiler vim-common locales libcurl4-openssl-dev zlib1g-dev \
  liblz4-dev libprotobuf-dev spatialite-tools luajit

Run ./setup.sh once to fetch the submodules and build the vendored tools.

Quick start

cd cairn && cargo build --release -p cairn-cli   # target/release/cairn

export AREA=rhone-alpes

cairn download --area $AREA        # OSM extract from Geofabrik
cairn basemap  --area $AREA        # vector basemap
cairn routes   --area $AREA        # route relations
cairn elevation --area $AREA       # .hgt tiles
cairn terrain  --area $AREA        # terrain-RGB
cairn valhalla-tiles --area $AREA  # routing graph
cairn package  --area $AREA        # Valhalla package

Every step clips to the area's own boundary, downloading the .poly from Geofabrik the first time it needs it. Pass --poly-shape to clip to something else.

cairn state --area $AREA reports which outputs exist; cairn state --area $AREA clear <step> removes one.

Tuning

Each step's defaults reproduce the builds documented in docs/pipeline-reference.md — an untouched run gives you the same bytes as the reference pipeline. Tests parse that document and compare it against the defaults, so the two cannot drift apart.

cairn options basemap            # every flag, with what it costs
cairn options basemap --presets  # and the option sets that ship

Two presets ship per planetiler step: measured (the default) and stock (planetiler's own defaults, as a comparison baseline). Override anything with -o:

cairn basemap --area $AREA -o transportation_surface_detail=false
cairn basemap --area $AREA --preset stock

Some flags worth knowing about, all measured on a rhone-alpes build:

Flag	Effect
max_point_buffer=4	caps the buffer on point layers. place declares 256px — nine times a tile's own area — so leaving it uncapped costs tens of MB
landcover_merge_maxzoom	merges landcover polygons at z14, where most of the bytes are. −19% of that layer
transportation_surface_detail	road surface and tracktype on every class, +0.84%. Reaches 73% of tracks — the difference between riding and pushing
water_pool_tolerance=1	simplifies swimming pools, which carry ~99 vertices each for a shape a pixel across
drop_redundant_name_int	omits name_int where it duplicates name, −0.88%

The desktop app

cairn/ is also a desktop app over the same code: pick an area, tick the steps, watch the progress, and inspect the resulting tiles on a map.

cd cairn && npm install && npm run tauri dev

Repository layout

Path
cairn/	the app and CLI — core/ is the shared pipeline, cli/, src-tauri/, src/
scripts/	the original Python and shell pipeline, still runnable
planetiler/	vector tile generation, as a fork with this project's schema changes
valhalla/, prime_server/	routing
docs/pipeline-reference.md	every step as a raw tool invocation

Related

The planetiler fork carries the schema work this project depends on — POI selection, the landcover and route tuning, road surface detail. Changes land in farfromrefug/planetiler-openmaptiles and are picked up here as a submodule bump.