The most detailed and freely available maps of the Himalayas are those published by the Survey of India (SOI). Initially created as part of the The Great Trigonometrical Survey in the 18th century (en.wikipedia.org/wiki/Great_Trigonometrical_Survey), the maps map the mountains in stunning detail and were recently made freely available to the public through the SOI web site as the Open Map Series (OSM).
Maps are made available as sheets of 1:50K scale (1cm on map = 500m on ground) of 28x28km in size. Each map sheet has a unique number. Let’s download the map sheet covering the Pangi valley around Saichu village. Below web site allows us to easily identify the sheet nr: 52d/9
https://www.indigeo.com/iMap.html#7/33.138/78.005
(Choose “Survey of India(SoI) – 50K Topo Map Index” in the layers / right toolbar)
Next, go to the SOI web site to download the sheet in PDF format:
https://onlinemaps.surveyofindia.gov.in/FreeMapSpecification.aspx
(login + enter 52d/9 + click download)
Survey Map Features
Let’s take a closer look at the downloaded map sheet. Open the PDF on your phone or laptop and zoom in 100% around the top left corner. You will see a treasure of terrain details appear, not available on any other maps:
Terrain types – forest (green), cultivation (yellow), open (gray), blue (glaciers), urban (red)
Vegetation type – open scrub, dense kail, open pine, etc
Rivers (blue) and streams (black) + names
Villages, hamlets (red squares) + names
Trails (red dots) and Paths (red dashes)
Roads (double orange) + tracks (double red dashes)
Peaks, Passes, Lakes + names
Bridges, Springs, Temples, etc
The above map features provide valuable inputs to plan and navigate unseen hiking trails.
Immense Dataset
To give you a rough idea of the amount of detail contained in the approx. 250 SOI map sheets spanning the entire Western Himalayas – Uttarakhand, Himachal, Ladakh and J&K:
2.000+ passes
2.000+ peaks
2.000+ alpine lakes
50.000+ settlements (useful for guidance, food, night stay)
1 lakh+ hiking trails (2.5 times the perimeter of the planet!)
100+ rivers / 1000+ streams
This is more then one can ever explore / hike in a single lifetime!
One important feature is missing in (most) Survey maps – contours. These have (probably) been removed due to (border) security reasons. This is not a major issue as we will see – in future modules – how to generate and overlay contours on Survey (and other) maps. We will also learn how to “geo-reference” survey maps and download them for offline navigation in our phone just like Open Street Maps. For now, we will just use them as manually referenced maps.
Route Planning
Let’s plan a sample traverse using the downloaded Survey map 52d/9 from Saichu village in the Pangi valley across the Ghordhar Jot to Karpath village in the Miyar valley. Similar to the route planning on Open Street Maps we can identify several important terrain features (except for elevation due to lack of contours) – refer maps below.
As you can see, without contours we lack valuable information on altitude / elevation and depend more on terrain features (villages, rivers, valleys) / changes in directions (N/E/S/W) to correlate our ground location with the map and find our way across the landscape.
Assignment
Similar as the above example, now plan yourself a hiking route between Tundah (Tund<h) in the Tundah Nala valley to Kunda (K#nda) in the Chanju Nala valley of Chamba. First identify and download the right Survey map sheet number and next list out the various terrain features along the way. Upload your maps with markings in a public folder and submit a link in the form below.
