Welcome to "Chapter 8 - Map Sources" of the Alpine Hiking Bootcamp. In this chapter we'll compare topographic maps of the Western Himalayas from various sources:

Module 1 - Olizane Maps
Module 2 - Soviet Maps
Module 3 - AMS Maps
Module 4 - Digitizing trails
Module 5 - Comparison

In module 1E we had already learned about Survey of India maps. Each Survey map covers 15'x15' or roughly 28x28km and has a scale of 1:50K (1cm on the map equals 500m on the ground). Contours have been removed from many (not all) Survey maps. It takes around 60 Survey maps to cover an entire Himalayan state.

Projection is UTM (Universal Transverse Mercator) and Datum WGS84. Survey maps were created as part of the Great Trigonometric Survey as are no doubt the most detailed available of the Himalayas. As of August 2021 the Survey made most of the maps available to the public.