Geography guide
Map projections and country size: why the world changes shape on a screen
A globe is curved and a browser is flat. A map projection is the mathematical rule that converts latitude and longitude into screen coordinates. Every projection preserves some properties better than others, which is why country shapes and apparent sizes can change from one map to another.
There is no distortion-free flat world map
Flattening a sphere-like surface forces trade-offs. A projection may preserve area, direction, local shape, distance from a chosen point, or a useful visual balance, but it cannot preserve all of those properties everywhere at once.
This is why judging country size from a familiar wall map can be misleading. The amount of distortion usually changes with latitude and with the projection's design.
Daily Geo uses different projections for different jobs
World map: Natural Earth projection
Geo Triangulation uses D3's Natural Earth projection for a balanced whole-world view. It is designed for readability rather than exact measurement from screen pixels.
Local neighbor map: azimuthal equal-area
What's Around Me? centers an azimuthal equal-area projection on the local country cluster and fits that cluster to the available viewport.
Border Fragment: fitted outline coordinates
The border round fits the selected outline fragment into its SVG viewport while preserving north-up orientation. The displayed scale is intentionally not a clue.
Screen distance is not geographic distance
A line that looks short on a projected world map is not automatically a short route over Earth's surface. That is why Geo Triangulation does not measure the number of pixels between two countries.
The game calculates great-circle distance from latitude and longitude using the Haversine formula. The projection is only the visual layer. The geographic calculation stays in spherical coordinates.
The Geo Triangulation guide explains that calculation in more detail.
Country area is stored separately from the map drawing
When Geo Sort asks for countries from smallest to largest, it does not estimate area from the rendered shape. Daily Geo uses the country area field in its normalized metadata.
This separation is important. If the game tried to infer country size from projected screen area, the answer could depend on the chosen projection. Using the metadata value gives one stable ordering rule.
Why polar and high-latitude regions often look unusual
Many projections stretch, compress, or reshape high-latitude regions more strongly than places near the equator. A country can therefore appear visually wider or larger than its actual surface area would suggest.
The right response is not to find a single “correct-looking” flat map. It is to match the projection to the task. Whole-world browsing, local adjacency, area comparison, and distance measurement are different problems.
What to remember while playing
- Do not infer exact distance from screen pixels.
- Do not infer true area from how large a country looks on the world map.
- Use relative direction and neighboring shapes as clues, not projection precision.
- For Geo Sort area questions, trust the ordering task rather than visual map size.