I’ve noticed that many cities have a river running through them or are located on a coast. I looked at the top 100 US cities by population and the top 83 world cities by population on a map and noted if it had a river, coast, both, or neither.
70% of the top cities in the US have a river and or a coast. The biggest city that has neither is #16 Charlotte.
In the US, you can only have so many cities on the coast. Some cities are in the middle of the country. Around the world, there is plenty of coastline available for cities, so more cities are able to locate on a coast. The Coast and Both categories go up because of this. 76% of the world’s biggest cities have a river and or a coast.
Do bigger cities have more rivers and coasts? We can encode the geography as a number. Both=2, River=1, Coast=1, Neither=0. I put the US cities in groups of 10 and graphed the average of each group.
There is a significant difference between the 10 biggest and the middle 70. There is also a significant difference between the middle 70 and the 20 smallest.
For the world cities, there’s not much difference in the geography as you move down the ranks until the end. Perhaps this is because even the smaller cities are able to have their own location with a river or coast. In the US, there are fewer of those spots, and the drop off happens sooner.