Map series of India and the neighbouring countries are prepared in sheets numbering from 1 to 105. These are called million sheets. Each million sheet is divided into 16 parts. Degree sheets are also divided into 16 parts.
Million sheets
The million sheets covering 4° latitudinal and 4° longitudinal extent are prepared in the scale 1:1000000. Each of the sheets in this category is divided into 16 parts known as degree sheets
Degree sheets
Each million sheet is divided into 16 parts in the order A, B, to P. Each of these sheets with 1 ° latitudinal and 10 longitudinal extent are known as degree sheets. They are prepared in the scale 1:250000.
Each degree sheet is divided into 16 parts with 15’ latitudinal and longitudinal extent. These sheets are prepared in 1:50000 scale.