Malaysia learning maps — reviewed 22 October 2026

Boundaries, river lines and marine polygons: Natural Earth, 1:10m data,
public domain. https://www.naturalearthdata.com/about/terms-of-use/
Pinned source revision: ca96624a56bd078437bca8184e78163e5039ad19
https://github.com/nvkelso/natural-earth-vector/tree/ca96624a56bd078437bca8184e78163e5039ad19/geojson
Files: ne_10m_admin_1_states_provinces.geojson,
ne_10m_rivers_lake_centerlines.geojson,
ne_10m_geography_marine_polys.geojson.
Retrieved 22 October 2026. Selected original vertices are checked in as
scripts/malaysia-admin-source.geojson and scripts/malaysia-water-source.geojson.
scripts/malaysia-context-land-source.geojson dissolves all administrative land
inside the map frame, including neighbouring countries, from the same source.

All thirteen states and three federal territories are retained separately.
ISO 3166-2 keys MY-01 through MY-16 identify the sixteen areas. Penang is shown
with its island and mainland sections. Kuala Lumpur and Putrajaya are separate
from Selangor, and Labuan is separate from Sabah. Display name Penang replaces
Natural Earth's Pulau Pinang. The boundaries are teaching references, not
survey data or a representation of international or maritime claims.

Shared boundaries are simplified together with Shapely coverage_simplify at
0.001 degrees. Six-decimal coordinate precision is retained in output. Small
territories remain selectable by zooming. Natural Earth's coastline is
generalised; actual city coordinates at Kota Kinabalu, Sandakan and Tawau can
lie up to approximately 2.3 km outside the reference coastline. They have not
been moved inland to fit it. Parent-area validation allows a 0.03-degree margin.

The source labels the Rajang/Rejang main course "Bajang". Its course across
central Sarawak and through Sibu is mapped explicitly to Rajang River; it is
not a separate river named Bajang. River control locations and independent
geographic tests check the Pahang, Rajang and Baram. River lines are clipped
to Malaysia with a 0.03-degree margin for source generalisation. They do not
show every tributary, navigability, seasonal flow or current flooding.

Marine polygons show the Strait of Malacca and South China, Sulu and Celebes
seas inside the displayed frame. All source land, including neighbouring
land, is removed from their hit areas. They identify named bodies of water,
not territorial seas, exclusive economic zones or sovereignty claims.

Twenty city coordinates, clues and explanatory notes are curated in
scripts/malaysia-map-places.json. Coordinates use [longitude, latitude].
Names and city identities can be checked through the corresponding Wikipedia
articles linked by the map. The twenty-city set is selective, not a ranking
or a complete list of Malaysian cities.

Rebuild at the repository root:
  python3 -m pip install shapely==2.1.2
  python3 scripts/build-malaysia-maps.py

The builder uses only checked-in inputs and writes the three public GeoJSON
files, src/lib/atlas/my.ts and src/lib/atlas/malaysia-places.ts. The same
geometry supplies both the playable rounds and the atlas previews.