If the prime meridian was today's , — of — countries / regions would have a standard-time meridian on their territory.
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Hit on this land
Hit elsewhere in country
Not hit
Where should Greenwich have been?
At the 1884 International Meridian Conference in Washington, the meridian through Greenwich Observatory was adopted as 0°. As a consequence, many countries ended up with no standard-time meridian (every 15° from Greenwich) on their own territory — the Netherlands, Switzerland, Israel, the Koreas, New Zealand, and over a hundred more all use a UTC offset whose nominal meridian falls just outside their borders.
What if a different point had been chosen as 0°? Which placement would have given the most countries / regions a standard-time meridian on home soil? Just a what-if exploration.
How to use
Drag the map left / right to move the new prime meridian in real time
Click / tap a country or region to see its coverage status
"Most covered" — an optimal placement, covering 109 (vs. 104 for today's Greenwich)
"Fewest covered" — a worst placement, covering only 85
"Most covered" / "Fewest covered" each have 24 equivalent positions on Earth (one every 15°); the dropdown jumps to the nearest one from the current view so the animation is short
"Today's 0°" and "Greenwich" are subtly different — the IRM (modern WGS84 / GPS 0°) is about 102 m east of the brass-strip Airy meridian that was the "Greenwich meridian" from 1884 to 1984
Map legend
Dark green: this very landmass has a new standard-time meridian passing through it
Pale green: same country / region has a meridian elsewhere, but this land doesn't
Pink: no land in this country / region has a meridian on it
Data sources
Country geometry: Natural Earth 1:10m Admin 0 Countries (Public Domain / CC0), converted to TopoJSON with light simplification
258 features / 4274 polygons are handled. Counts are based on the 1:10m data; very small islands (a few meters across) may be omitted by Natural Earth.