A set of over 7,000 historical maps of South Asia produced by the Survey of India or the Survey of Pakistan, at scales of one inch per mile (1:63,360) or the more modern metric scale of 1:50,000. These maps cover the territory of present day Pakistan, India, Nepal and Bangladesh, and in general were produced during the 20th century. Each map covers an area of 15 minutes latitude by 15 minutes longitude, and thus there are a total of 256 individual 63k maps to cover a 4 degree by 4 degree block. The file naming convention is to give first the number of the 4 degree x 4 degree block followed by the letter (A to P) of the sixteen 1 degree x 1 degree blocks in each 4 degree block eg. 38 D, and this is followed by a "]" symbol to indicate a s...