Russia on the Map — regional map source and processing notes
Prepared 2026-11-13

GEOMETRY
Provider: Natural Earth.
Dataset: ne_10m_admin_1_states_provinces, scale 1:10 million.
Project: https://www.naturalearthdata.com/
Repository: https://github.com/nvkelso/natural-earth-vector
Pinned commit: ca96624a56bd078437bca8184e78163e5039ad19
Original file:
https://raw.githubusercontent.com/nvkelso/natural-earth-vector/ca96624a56bd078437bca8184e78163e5039ad19/geojson/ne_10m_admin_1_states_provinces.geojson
Original SHA-256: 22d0e3ad85eb3e27f17cabf8ba2d50e554fbc27a87796ff891d958185da62fb5

LICENSE
Natural Earth map data are public domain, including permission to modify and
redistribute them. Terms: https://www.naturalearthdata.com/about/terms-of-use/
Suggested credit, included in the SVG metadata: Made with Natural Earth.
Natural Earth credits Tom Patterson, Nathaniel Vaughn Kelso and contributors.
Its multilingual name data are derived from Wikidata under CC0.

SELECTION AND BOUNDARY CONVENTION
The contest's requested catalogue has 89 entries. It is assembled from the
85 named features whose source admin field is Russia plus these four original
Natural Earth features:
UKR-327 — Donetsk oblast geometry, displayed as Донецкая Народная Республика.
UKR-329 — Luhansk oblast geometry, displayed as Луганская Народная Республика.
UKR-331 — Zaporizhzhia oblast geometry, displayed as Запорожская область.
UKR-4827 — Kherson oblast geometry, displayed as Херсонская область.
The complete source administrative outlines are used. They are not current
lines of military control. Inclusion follows the site's contest specification;
this derived selection does not alter the upstream administrative metadata.

The source treats Crimea and Sevastopol as RUS-283 and RUS-5482 but retains
UA-43 and UA-40 ISO fields. Source feature IDs and original metadata are kept
in source/natural-earth-selected.geojson for traceability.
Application IDs RU-CR, RU-SEV, RU-DNR, RU-LNR, RU-ZAP and RU-KHE are local
identifiers for this application, not a claim that they are assigned ISO codes.
The unnamed source feature RUS+99? (a small island with no region assignment)
is not a separate catalogue entry and is excluded.

NAME AND ID CORRECTIONS
RUS-2364 is Moscow Oblast: application ID RU-MOS.
RUS-2365 is Moscow city: application ID RU-MOW.
These correct the swapped ISO values in the selected upstream file.
RUS-2399 is Altai Krai, not Altai Republic: the incorrect translated labels
are corrected without changing its geometry. RUS-2400 remains Altai Republic.
Russian republic names are expanded for readability; English Oblast suffixes
and the name Jewish Autonomous Oblast are supplied where necessary.

PROCESSING
source/natural-earth-selected.geojson contains the selected original coordinate
arrays unchanged, with only relevant properties retained.
tools/build-map.py projects them to spherical Albers equal-area coordinates:
central meridian 100 E, latitude of origin 60 N, standard parallels 50/70 N.
Longitudes are normalized around 100 E so Chukotka remains contiguous across
the geographic +/-180 meridian. No regions are manually drawn or moved.
Coordinates are fitted to a 1440 x 760 viewport, rounded to 0.1 screen pixel,
and consecutive duplicate points are removed. Sub-pixel collapsed rings are
omitted from the SVG; their full coordinates remain in the source GeoJSON.
Build details and SHA-256 values are recorded in build-report.json.

FILES AND INTEGRATION
russia-regions.svg — all 89 region paths, accessible titles and data attributes.
russia-regions.svg.gz — deterministic gzip copy; serve with Content-Encoding:
gzip and Content-Type: image/svg+xml when using this precompressed file.
data/regions.json (repository root) — catalogue generated with the SVG.
Each path has id="region-RU-...", class="map-region", data-region-id,
data-name-ru, data-name-en, title, tabindex="0" and role="button".
The application supplies click and keyboard actions. SVG group id=map-regions.
The JSON also contains svg_bbox, label_x and label_y for zoom-to-region helpers.
The source is self-contained; no external service or tile server is required.

ENGLISH DISPLAY NAMES (2026-11-14)
data/region-names-en.json is the complete local editorial source for name_en
and short_name_en. The generator applies these names by stable application ID;
it does not modify geometry, source feature IDs or Russian names. Full names
include the region type, and short names are used for the presentation opening.
See docs/REGION-NAMES.md for the convention and reviewed primary references.
The English-name source hash is included in build-report.json.