Pitney Bowes MapInfo Professional - Manual (Page 393)

Understanding Coordinate Systems
You can make a map out of any globe without distorting the points on the surface by placing the globe
into an imaginary cylinder.
Globe with Longitude/Latitude Projection
If you transfer the touch points from the globe surface onto the cylinder and roll out the cylinder onto
graph paper, the result is a map as in the figure below. In the map that would be created from this cylinder,
the Equator is 0 degrees all the way around the globe and the points on that line are completely accurate.
Longitude/Latitude Projection Map
When you add longitude and latitude lines at 15 degree increments to each side of the Equator and the
Prime Meridian you create a reference grid. The lines furthest from the Prime Meridian are +180 degrees
toward the right and -180 degrees to the left. This map projection is commonly called the
Longitude/Latitude projection.
This is often considered the default projection. It is the most effective map for areas nearest the Equator
but measurements further away tend to increase in distortion.
Because many people do not live near the Equator, other projections came into use to create more
accurate local maps. Accuracy depends upon how you project the globe onto the cylinder. If you turn
393 MapInfo Professional User Guide
Chapter 15: Working with Coordinate Systems and Projections