a seriesNatural Earth country outlines

The country shapes every map on this site is drawn with. Natural Earth's Admin 0 countries at 1:110 million, fetched once and simplified: 220 country rows, 357 rings, 6,571 coordinate pairs at two decimal places. A closer file sits beside it for the detail maps — the same 220 countries from the 1:50 million source, 1,303 rings and 29,823 points at three decimal places. Public domain, in the publisher's own words: "No permission is needed to use Natural Earth."

The coarseness is deliberate. These maps are about nine hundred pixels wide, and a coastline drawn finer than a pixel costs bandwidth and shows nothing; the rings are reduced by Douglas–Peucker at 0.2° for the world map and 0.05° for the close-ups.

The file's join key is what matters for the rest of the site. Every chart, table and country page keys on ISO 3166-1 alpha-2, and Natural Earth leaves that field as -99 for a handful of places, so tools/fetch_geo.py patches five by name: France and Norway, whose codes sit on dependency rows, and Kosovo, Somaliland and northern Cyprus, which have no ISO alpha-2 at all. The patched codes — XK, XS, XN — are placeholders this project chose, and they will not match a World Bank series, because no such series carries a row for them.

Inference — that is not a technicality for this subject, and one of the placeholders is worse than a blank. XN in the World Bank's tables is not a place at all but the aggregate Lower middle income, which carried 0.71 physicians per 1,000 in 2022 — so a map that joined blindly on the code would paint northern Cyprus, a fertility destination this directory writes about, with an income group's average. Taiwan has an ISO code and an outline here and carries no value in any of the five World Bank series on this disk. Monaco, Macau and the Vatican have no polygon at all.

tools/fetch_geo.py downloads the GeoJSON from the Natural Earth vector repository, keeps every country with an ISO alpha-2 code, simplifies each ring and rounds coordinates. The 1:110m file omits several small states, small island states and city states; those are filled in from the 1:50m file so the country list is one list.

Names in the file are the file's own: Turkey rather than Türkiye, United States of America, Dem. Rep. Congo. This site carries its own names in the records and uses the outlines only for geometry. Natural Earth's terms add that its authors "are not responsible for any problems relating to accuracy, content, design, and how it is used", and boundaries drawn at this scale are a cartographic convenience, not a statement about a border.