Defence Series Maps
Also called: DSM · Topic: Topographical Maps: Relief Representation and Interpretation · NCERT: Beyond NCERT
Meaning
Defence Series Maps (DSM) are Survey of India topographic maps that show the land in full detail. They include sensitive installations and vulnerable areas. The National Map Policy 2005 split Survey of India maps into two series, and DSM is one of them. These maps stay on the older mapping system. They are kept for the armed forces and national security and are not sold to the public. This lets India keep detailed maps for defence while a separate open version serves everyone else.
Example
Survey of India has mapped the Ganga stretch in Mirzapur and Varanasi districts of Uttar Pradesh (sheet 63K/12) at 1:50,000. In the Defence Series version, any sensitive installations stay on the map. In the Open Series version, they are taken out.
Don't confuse with
- Open Series Maps: these come from the same 2005 policy, but they are made for civil and development use. They use the WGS-84 datum and UTM projection, sensitive features are removed, and the public can get them.