Open Series Map

'Open Series Map' have been introduced as per the National Map Policy of 2005 by Survey of India. For the same a new map numbering system has been adopted instead of the previous India and Adjacent Countries (IAC).

The map series is based on Transverse Mercator projection on WGS-1984 datum. A numbering system based on International Map of the World (IMW) is used.

Map numbering is of the form 'A-12A-1':

  1. The IMW numbering system with minor modification is used upto 1°×1°/1:250,000 scale.
    1. Since the IMW map number for India will always start with 'N' (India being in the northern hemisphere), the first letter is omitted.
    2. The next alphabet and number of the IMW map number denotes the 6°×4° region of the IMW series. So sheet with Kalyanpur (77.65489°E 24.11981°N) would be in 'G-43' (from NG-43):
      Open Series Map (OSM) map numbering 6°×4° index
    3. Each 6°×4° rectangle is further subdivided into 24 squares of 1°×1°. Each square is indicated serially by an alphabet increasing first towards east and then towards south, starting with 'A'. So sheet for Kalyanpur (77.65489°E 24.11981°N) falls within 'G-43X':
      Open Series Map (OSM) map numbering 1°×1° index of 6°×4° - G-43
  2. Each 1°×1° square is further divided into 16 squares of 15'×15' (15 minutes×15 minutes). Each square is indicated serially by a number increasing first towards south and then towards east, starting with '1' (similar to the system adopted in India and Adjacent Countries). So for the map sheet for Kalyanpur (77°39.293'E 24°7.187'N) would be 'G-43X-12':
    Open Series Map (OSM) map numbering 15'×15' index of 1°×1° - G-43X

Lookup Open Series Map map numbers in Map Number Lookup.

Further Reading/References