The term grid sector was created by SLGI team to help improve Geographic research.
A grid sector is a part of the map, divided by latitude and longitude lines. A grid sector is a square covering the surface of 10 000 sims ( a row of 100 sims from East to West and a row of 100 sims from South to North). Coordinates are used to divide map into grid sectors.
World coordinates for every sim show position in latitude and then in longitude. Borders between every grid sector are defined by a round number, a multiple of 100. For example, Grid Sector J10 contains sims at coordinates 1000-1100/1000-1100.
Grid sectors are named by using a capital letter and a number, in the same way squares on a chess board are named. The letter indicate their longitude and the number their position on latitude.
The Microsector is the subdivision of a grid sector.