04 Latitude And Longitude

Question 1

Describe the Geocentric Latitude

Answer 1

• Geocentric Latitude is the angle from the equator to the position with the origin at the centre of the Earth.
• This is not particularly accurate as the Earth is not a perfect sphere
• Represented by the angle Psi

Question 2

Describe Geodesic Latitiude

Answer 2

• Angle from the plane of the equator to the position such that the line is perpendicular to the surface of the Earth
• As such the origin is rarely in the centre of the Earth
• Represented by the angle Phi

Question 3

When is the Geocentric Latitude equal to the Geodesic Latitude?

Answer 3

At the equator and each pole

Question 4

Where is there the greatest difference between the Geocentric Latitude and the Geodesic Latitude and how big is it?

Answer 4

• At 45 degrees North and South

- 11 degrees 6 mins

Question 5

What are the rules regarding calculating a change in latitude?

Answer 5

• If both latitudes are in the same hemisphere then subtract one from the other
• If each latitude is in a different hemisphere then add the two together
• If longitudes are given and they add to 180 degrees then the shortest distance will be over the pole