With the National Map Policy of 2005, two series of maps were introduced for India:
1. Open Series Map (OSM) - for civilian use.
2. Defense Series Map (DSM) - for defense use.
DSM maps (and projection system) have following properties:
1. Datum: WGS84
2. Projection: LCC
India has been broken into twenty four zones. Each zone is 8 degrees wide (west to east) and 6 degrees high (south to north). Arrangement of zones is as in image.
Rough derived projection properties:
1. Central Latitude for zones are:
_C N39:00:40
_D N33:00:32
_E N27:00:25
_F N21:00:19
_G N15:00:13
_H N09:00:08
2. Central Longitude for zones are:
5_ E72
6_ E80
7_ E88
8_ E96
3. Scale factor for zones are:
_C 0.999304
_D 0.999304
_E 0.999304
_F 0.999305
_G 0.999305
_H 0.999305
4. False easting/northing is 500000m.
Refer: https://dst.gov.in/sites/default/files/nationalmappolicy.pdf
