Features of the grid system : 

1. The lines that run vertically are called eastings and those that run horizontally are called northings. 

2. Eastings and northings cross each other to form a square called as a grid square. 

3. The starting point or the reference point is the exteme south-west grid or the one at the bottom left corner. 

4. The numerical value of eastings increases eastwards beginning from the southwest corner. Similarly, the numerical value of northings increases northwards. 

5. Eastings and northings are always given in two digit numbers. Even 0 is read as 00. (For example, 01, 02, 03, 98, 99.) 

6. When referring to a grid, eastings are always stated first. 

7. Eastings and northings on a topo sheet drawn on a scale of 1 : 50,000 are always 2 cm apart, which means they represent a distance of 1 km on the ground. So, the area of 2cm × 2cm on the map represents 1 km × 1 km on the ground. 

8. There are two types of grid references :

(a) The four – figure reference

(b) the six-figure reference.