GPS Coordinates

You need to pick one Lat line and one Long line and set those to 0.

So if 43.8 if the center line between North and south subtract 48.3 from all Lat values, negative values end up in the south, positives in the north. Do a similar thing for East and West.

Lets assume you pick -79.4 as your Long value, I am going to assume anything more negative is West, less negative is east.

you would do the following -

For location (43.743, -79.427)

( 43.743 - 43.8 ) = - (South)
( (-79.427) - (- 79.4) = - (West)