Copenhagen Phase 1: scaffolding + area + OSM download

- pyproject.toml with all deps (geopandas, contextily, partridge, etc.)
- config/: area.json (3 OSM boundary relations), modes.yaml (subway/s_tog/
  light_rail/regional/bus, S-tog scoped to route=light_rail network=Takst),
  styling.yaml (zorder/widths/colours/palette/mask/labels)
- build_area.py: fetch 3 relations via OSM API, stitch rings, dissolve to
  area.gpkg/area.geojson (City Pass approximation)
- download_osm.py: per-mode Overpass (mirror+backoff, out geom + recurse for
  stops), writes {mode}.gpkg (lines+stops) + query text
- download_gtfs.py / gtfs_to_geopackage.py: stubs (blocked on Rejseplanen)
- data/ gitignored (regenerable); output/ tracked

copenhagen/config/area.json

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+{
+  "description": "City Pass area approximation: Copenhagen Kommune + Frederiksberg Kommune + Amager island (dissolved).",
+  "source": "OpenStreetMap API relation/{id}/full.json",
+  "relations": [
+    {"name": "Kobenhavns Kommune", "id": 2192363},
+    {"name": "Frederiksberg Kommune", "id": 2186660},
+    {"name": "Amager", "id": 5175924}
+  ]
+}

copenhagen/config/modes.yaml

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+# Mapping of map modes to OSM route filters, GTFS route types, and style keys.
+# `style` references a key in styling.yaml.
+#
+# OSM filter keys map directly to Overpass tag filters. A key suffixed with
+# `_neq` emits a negated tag filter (["k"!="v"]); any other key emits an
+# equality filter (["k"="v"]). The bbox is appended by download_osm.py.
+#
+# S-tog are tagged route=light_rail in OSM (NOT route=train); they are scoped
+# by network="Takst Sjælland". The separate `light_rail` mode catches other
+# light rail (e.g. Hovedstadens Letbane, opened Aug 2026) via network!=Takst.
+# GTFS route_type: 0=tram,1=subway,2=rail,3=bus,4=ferry.
+modes:
+  subway:
+    osm:
+      route: subway
+    gtfs_route_type: 1
+    style: metro
+  s_tog:
+    osm:
+      route: light_rail
+      network: "Takst Sjælland"
+    gtfs_route_type: 2
+    style: s_tog
+  light_rail:
+    osm:
+      route: light_rail
+      network_neq: "Takst Sjælland"
+    gtfs_route_type: 2
+    style: light_rail
+  regional:
+    osm:
+      route: train
+    gtfs_route_type: 2
+    style: regional
+  bus:
+    osm:
+      route: bus
+      network: Movia
+    gtfs_route_type: 3
+    style: bus

copenhagen/config/styling.yaml

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+# Styling for the Copenhagen transit map. Referenced by render.py and prepare.py.
+# Colours keyed by `style` (from modes.yaml) then route ref.
+# zorder is draw order bottom->top (higher drawn later / on top).
+
+zorder:
+  bus: 1
+  s_tog: 2
+  light_rail: 3
+  regional: 4
+  metro: 5
+
+line_width:           # body width in points (outline = body + outline_width)
+  bus: 0.8
+  s_tog: 2.0
+  light_rail: 2.0
+  regional: 1.8
+  metro: 2.6
+
+outline_width: 1.2    # added to line_width for the dark casing
+outline_color: "#2b2b2b"
+
+alpha:
+  bus: 0.45
+  s_tog: 0.95
+  light_rail: 0.95
+  regional: 0.9
+  metro: 1.0
+
+# Fallback palette when no GTFS route_color and no OSM colour tag are present.
+# Metro / S-tog values mirror the OSM colour tags (verified). Regional trains
+# have no OSM colour, so the palette supplies one.
+palette:
+  metro:
+    M1: "#008d41"
+    M2: "#ffc600"
+    M3: "#ff0a0a"
+    M4: "#009cd3"
+  s_tog:
+    A: "#00a4eb"
+    B: "#50ae30"
+    Bx: "#adce6d"
+    C: "#f68b1f"
+    E: "#7670b3"
+    F: "#fcc019"
+    H: "#e63511"
+  regional:
+    default: "#7a1b3e"
+  light_rail:
+    default: "#e89b3a"
+  bus:
+    A: "#d6264a"
+    C: "#16a085"
+    S: "#2a6fb5"
+    default: "#c8a80e"
+
+bus_filters:
+  # ref-based bus categorisation (regex applied to route ref)
+  categories:
+    A: "^\\d+A$"
+    C: "^\\d+C$"
+    S: "^\\d+S$"
+    regular: "^\\d+$"
+
+mask:
+  fade_distance_m: 2500   # shapeburst fade width outside the area
+  max_alpha: 0.85
+  color: white
+
+basemap:
+  provider: CartoDB.PositronNoLabels
+  zoom: 14
+
+labels:
+  show: true
+  styles: [metro, s_tog]   # which station types to label
+  min_fontsize: 5
+  max_fontsize: 9