to calculate mean of gps

hello friends.
I have two gps lat and long..i want to get mean of lat and long..my lat and long is an array type data.how can i convert this array data int decimal.

adding the latitudes and divide by 2? works only if they are nearby.
NB. if the points are on opposite sides of the earth the average should be in the core?

can you post a real example ?

Maybe this is easier to convert the angles to a double first

my Angle Class can do that - Angle library - Libraries - Arduino Forum