Suppose I have geographic coordinates of "Saratoga, California, USA" as
Latitude: 37°15.8298′ N
Longitude: 122° 1.3806′ W
I know from here that in case of latitude 1° ≈ 69 miles
and that longitude varies:
1° longitude = cosine (latitude) * length of degree (miles) at equator.
How many miles is 1° longitude at longitude: 122°1.3806′ W
?
Best Answer
It doesn't matter at what longitude you are. What matters is what latitude you are.
Length of
1 degree of Longitude
=cosine (latitude in decimal degrees) * length of degree (miles) at equator
.Convert your latitude into decimal degrees ~ 37.26383
Convert your decimal degrees into radians ~ 0.65038
Take the cosine of the value in radians ~ 0.79585
1 degree of Longitude = ~0.79585 * 69.172 = ~ 55.051 miles
More useful information from the about.com website:
Note that the original site (about.com) erroneously omitted the "nautical" qualifier.