What is the rules to find the difference of longitude?

Answer 1

The difference in longitude between two places is:

Absolute value of [ (one longitude) minus (the other longitude) ].

The easist way to calculate it is as follows:

--> If both points are in the same hemisphere

(both east longitude or both west longitude):

-- Subtract the smaller number from the larger number.

--> If the points are in different hemispheres

(one east longitude and one west longitude):

-- Add the two numbers.

-- Subtract the result from 360.

Answer 2

To find the difference of longitude between two points, subtract the longitude of the first point from the longitude of the second point. If the result is greater than 180 degrees, subtract it from 360 degrees to find the shortest angular distance between the longitudes.