How to use it
- Press My location, type a place, or click the map.
- Read the nearest town, the nearest city over 100,000 people and the nearest over a million.
- Click a row in the table to fly to that place.
5 practical uses
- Find the nearest town from a remote spot for fuel, food or help.
- Name the closest city to a coordinate in a report or a log.
- Find the nearest big city to a small town for flights or trains.
- Check the nearest places to a property or a campsite.
- Locate a point by its nearest city in a message.
The maths behind it
The haversine great-circle distance from the point to the centre of every place in the data is computed, and a small heap keeps the nearest for each population threshold. A big city has only one centre point, so in its outer districts a smaller neighbour's centre can be nearer. To find the place you are in, each place also gets a circle that grows with its population (13 m × the square root of its population: about 12 km for Liverpool, 900 m for a town of 5,000). Of the circles that hold the point, the one the point is deepest inside is the place you are in. That place is always in the list, and for the city rows it comes before a nearer centre. The direction is the initial bearing to each place.
Notes
Cities and towns come from GeoNames (CC BY 4.0): every populated place with 5,000 or more people, 46,000 of them, with the population GeoNames records, which for a city is usually the municipality rather than the metropolitan area. Distances are to the centre point of each place.
Distances are straight lines. The nearest town by road can be a different one; see the driving distance for that.