A question of latitude

[hiflier]

I want to know the formula for calculating the small circle distance ie distance round the earth of a parallel of latitude, using the numerical degree of that latitude and the actual circumference of the earth at the equator.

[Buenchico]

http://mathforum.org/...rmath/view/54158.html

[jomifl]

cos.latitude X equatorial diameter
eg lat. 45degrees =0.707
.707 X 25000miles(nominal equatorial diameter)
=17,677miles

[vascop]

You wanted a formula for the circumference at latitude L degrees. Here it is:
If C=circumfence at equator
c=circumference at latitude L degrees, then
Formula is
c=C x cos L

[mibn2cweus]

Here are stats for Equatorial circumference:

40,075.035535 kilometres (24,901.472609 mi) in IAU-1976 and IAU-2000

http://en.wikipedia.o...length_of_the_equator