On Saturday, March 10, 2018 at 7:19:47 PM UTC-6, wrote:
On Saturday, March 10, 2018 at 12:00:20 PM UTC-8, jfitch wrote:
But a mile is actually a useful unit, in context, as is a pound and a ton.

One degree of latitude is 60 nautical miles, and one minute is a nautical miles which is 6000 feet. Makes for some easy math measuring distance on a chart.

Not as simple using the metric system...

On 1:500 000 scale charts 1 cm represents 5km exactly. 1 inch more or less 8 miles.
On 1: 1000000 scale charts 1 cm represents 10km exactly 1 inch more or less 16 miles.