Digital Mapping of Himalayan Trails

Peter Van Geit

During my initial foray into the Indian Western Himalaya in the summer of 2018, I realized the significant difficulty of planning an alpine style journey due to the absence of detailed, publicly available maps. It took me weeks of reading through blogs, searching for GPS logs and scanning hi-res satellite maps to finalize a 1500 km long traverse across 43 high altitude passes. Aside from the well-known commercial / tourist destinations, it was hard to find details on the lesser-known regions of the Himalaya. In the following years and 5000+ km of subsequent explorations covering 160 lesser-known passes I decided to start publicly mapping the Himalaya, a massive effort that would open up the roof of the planet to alpine hikers around the world.

Map Sources

Hikers in the Alps, the Nepal Himalaya in or the mountains in the US, have detailed maps at their disposal. When it comes to the Indian Himalaya, public maps are scarce. For Ladakh and northern Himachal the Swiss Olizane maps cover approx. 200+ high passes. These are fairly expensive (mostly used by Europeans), large size paper maps at a 1:150K scale. They are useful as reference for clearly marked routes in Ladakh but less accurate for lesser trodden routes. Olizane is one of the few maps that have contours, essential for hikers to understand the topography of the terrain. Another well-known commercial map series are the Leomann maps, at 1:200K and without contours, more schematic and much less accurate covering Kashmir to Uttarakhand.

During the cold war the Soviet military undertook a secret mapping project that covered the entire world in high detail, including the Indian Himalaya. These manually carto graphed maps are fairly detailed at 1:100K scale with a surprisingly accurate topography compared to modern day satellite elevation data. Covering the entire Western Himalaya, they hold a treasure of hiking routes. Similarly, the US army map service (AMS) map service has mapped India in 100+ detailed 1:250K scale sheets including the Himalayas although the larger scale and lesser resolution makes them of limited use to the hiker.

The first major effort to publicly map the Himalayas was done by Depi Chaudhry who explored the Western Himalaya extensively and accurately GPS recorded his routes. In 2015 he created a beautiful topographic map including 1000+ km of routes covered across 50+ high passes from Uttarakhand to Kashmir. He tried publishing his maps and hiking routes in both print format and through a mobile app but unfortunately his efforts were not realized. A 17x17 feet copy is displayed at the Indian Mountaineering Foundation office in Delhi.

As part of the Great Trigonometrical Survey started in 1802, the British did the first accurate mapping of the Indian subcontinent. The Survey of India (SOI) was born and it took nearly 70 years to complete this mammoth mapping effort with scientific precision. Maps covering the Himalaya and geo-political sensitive border regions were generally not easily available to the public. Only recently when India opened up its mapping and geo-spatial data policy, did the Survey release the Open Series Maps to the public.

Detailed 1:50K scale maps can be downloaded from SOI’s Nakshe portal documenting the Indian Himalayas in stunning detail— countless high ranges, valleys, tens of thousands of remote settlements connected by lakhs of kilometres of remote trails and paths. One can download some 120+ map sheets covering the entire Uttarakhand and Himachal. As of now, only Ladakh, Jammu and Kashmir can be ordered offline.

Finally, if all the above fail, one can use publicly available high resolution digital satellite maps like Google Satellite, Microsoft Bing, ESRI or Maxar satellite imagery. These detailed visual maps reveal human settlements and connecting trails in remote mountain regions not yet digitally mapped on any other available maps. Frequently used hiking trails as small as 30 cm wide contrasting in the surrounding terrain can easily be spotted on hi-res. sat. maps. This of course is only possible in regions without forest or cloud cover, especially the high-altitude deserts of Ladakh, Zanskar, Lahaul and Spiti. Farming settlements in Kashmir, Himachal, Uttarakhand are usually clearings in forest and can therefore also be easily identified.

Another popular map source to study the topography of the terrain is Google Earth (GE). GE renders a Google Satellite map on a 3D digital elevation model. The user can view the terrain from different angles, heights and zoom levels providing an interactive way to view the topography including valleys, peaks and ridges. Although this animated view is visually appealing, using contour maps will be much more accurate in understanding the steepness of the terrain and planning your journey through the mountains.

The overview (facing page) shows the complete map coverage of the western Himalayas through available Olizane (purple), Soviet (green) and Survey maps (yellow). The 1:50K scale Survey map sheets, each cover an 15x15” area and offer the highest detail. The Soviet map sheets come in 1:100K scale covering 1.5x0.8” providing medium detail with manual, less precise topography. The 1:100K maps are not available for certain regions so we fall back on the less detailed 1:200K Soviet map sheets covering 3x1.6” each. Finally, the Ladakh region is mostly covered by the 1:150K Olizane maps with satellite generated contours, although being decades old and not regularly updated some hiking routes are less accurate.

Georeferencing Maps

A hard or soft copy of any map above is useful as a reference while hiking in the mountains. One can correlate the topography (valleys, ridges, peaks etc.) on the ground with the same features shown on the map to identify your position. Many Europeans refer to the large size Olizane map sheets to find their way along valleys and passes along frequented routes in the open, gradual landscape of Ladakh. This way of visual correlation between map and field is more challenging in steeper, densely forested terrain. A map generally becomes much more useful and accurate after georeferencing it. Georeferencing is the process of mapping the internal coordinate system of the map to a geographic coordinate system on the planet. It’s basically a projection system of how a region of our spherical planet is projected onto a two-dimensional map surface.

Commonly used coordinate system for our planet since the advent of satellite-based GPS (Global Positioning System) are longitude (east-west) and latitude (north-south position). Combined with elevation (altitude) it uniquely identifies each location on the planet. Your current position identified by your phone GPS can be real- time displayed on a geo-referenced map making field navigation much easier and more accurate. Boundaries of a map are usually marked with coordinates like latitude and longitude allowing you to accurately geo-reference the map along with its projection system and datum.

Once geo-referenced, the location of each object shown on the map (river, peak, village, trail.) can be correlated to its exact location on the planet. Using a Geographic Information System (GIS) one can digitize and extract these features along with their exact location and use them in any other mapping or mobile navigation app. Each map also has a scale indicating the ratio of distance on the map to the actual distance on the ground. On a 1:100K scale map 1 cm measured on the map corresponds to 1 km in the field. A lower scale 1:50K Survey map will therefore offer more detail and be more accurate than a higher 1:150K scale Olizane map.

In addition to identifying your exact position on the map, it’s equally important for the alpine explorer to understand the topography of the surrounding mountains for planning routes: valleys, ridges, peaks. It’s essential to understand the steepness of the terrain in order to plan your journey. Topographic maps show elevation through contour lines corresponding to lines of equal elevation. Each contour corresponds to a certain increase in altitude (e.g. 20 m). Closely spaced contours indicate steep terrain, wider spaced contours mark gradual slopes suitable to climb or descend.

The Shuttle Radar Topography Mission (SRTM) in 2000 was the first global effort to generate a Digital Elevation Model (DEM) of the entire planet. At a resolution of one arc-second (30 m) this was the first high resolution and accurate satellite based topographic mapping of the planet. DEM data is publicly made available through NASA or ISRO’s Bhuvan portal. DEM data can be used to generate contours and overlay the same on maps like the Survey maps (which lack contours most probably due to border security concerns) transforming these into much more useful topographic maps.

I planned and navigated my recent three-month winter exploration across 2000 km and 110 passes across the breadth of Uttarakhand using 60 geo-referenced Survey maps (each 15x15’ or 28x28 km) covering the entire state. Although created decades ago and lacking recent updates these heritage maps are surprisingly accurate and no doubt the most detailed account of the Indian Himalaya. Once digitally geo-referenced, the Survey and any of the above maps can be downloaded on any mobile app and used directly for navigation just like Google Maps on the phone. Your current location is shown in real-time directly on the map making navigation a breeze.

Sathyanarayan Venkatachari, a well-known solo hiker in the Indian hiking community was no doubt a pioneer in exploring the innermost regions of the Himalaya using geo-referenced maps a decade ago. He maintains an informative blog with detailed geo-tagged routes of his journeys and was knowledgeable on geo-referencing maps, generating contours and using GPS based navigation to plan his alpine style journeys. An inspiration to me, he unfortunately disappeared in summer 2018 during one of his solo journeys in Kinnaur while I was into my first Himalayan exploration.

GIS Databases

There are several GIS databases in the world containing geo-tagged data like GPS recorded trails and geo-locations of features useful to the hiking community including hamlets, passes, peaks, lakes, etc. The NGA (US National Geospatial Intelligence Agency) has a public dataset of thousand+ passes and tens of thousands of remote settlements in the Himalaya—a treasure for the alpine explorer. Open Street Maps (OSM) has probably the largest public set of geo-coded data describing the entire world; each feature is searchable by name. Anyone can contribute new terrain features, hiking routes, passes, peaks, campsites, rivers, shelters, lakes, remote roads, settlements through various free editors.

Two well-known public databases covering world-wide hiking routes are WikiLoc and Ramblr where hikers can upload and share recorded GPS logs. Both include hundreds of trails, mostly commercial and tourist hiking destinations in the Indian Himalaya and Sahyadri. Depi Chaudhry collected a large set of GPS recorded trails over a decade spanning Uttarakhand to Kashmir. In the summer of 2018 three Indian hikers completed the ‘Western Traverse’, a 950 km long continuous traverse from Ladakh to the border of Nepal crossing 27 high passes. The entire journey was GPS recorded. GPS logs from all above sources have been consolidated and mapped as hiking routes in Open Street Maps.

Open Street Maps

The most comprehensive data model and map in use by the worldwide outdoor community is Open Street Maps (OSM) – a collaborative project to create a free editable map of the world. The European Alps, Himalaya in Nepal and mountain ranges across the world have been mapped in great detail in OSM. Where Google Maps usually ends at the last road, OSM continues deep into the mountains. Combined with contours and used as a base map in numerous mapping sites and mobile navigation apps, OSM remains the map of choice for hikers around the world. The more visited regions in the Himalayas
like Leh-Ladakh, Dhauladhar range in Himachal and hiking routes in Uttarakhand are mapped in good detail in OSM.

OSM offers the easiest way to plan and navigate your alpine style journeys in the mountains. Advance route planning can be done through various mapping sites like OSM.org, OpenTopoMap.org or Waymarked Hiking Trails rendering the OSM dataset on satellite generated topographic maps showing valleys, peaks, forests, glaciers, cultivated land and human settlements. One can review the elevation profile of any hiking route and download an accurate GPS log. Various free mobile apps like OSMAnd (my favourite), OruxMaps, Maps.Me, etc allow OSM maps to be downloaded offline and any external GPS logs.

The apps show your current position on the OSM base map allowing you to navigate with ease along the hiking routes, indicating distance to the next campsite, river crossing or hamlet. Offline contours give you a clear understanding of the topography of the terrain including elevation gain to your next pass crossing.

Mapping the Himalaya

During the 2020 lockdown, I with a passionate group of volunteers set out to digitally map the Western Himalaya in OSM. It took us nearly half a year to map the Himalaya in high detail using various external maps sources and GIS databases. We initially mapped mountain passes which define beautiful hiking routes across high ranges connecting neighbouring valleys and districts. Overall, we identified 2000+ passes from Kashmir to Ladakh to Uttarakhand. We mapped 800+ glacial high-altitude lakes, well-known as well as remote and nearly inaccessible pilgrim destinations. We researched and mapped some 1000+ prominent peaks across the five mountainous states. Important for the alpine style explorer, we identified and mapped over 30,000 remote human settlements. These are key for route guidance, food supply and night stay.

We mapped hundreds of rivers (valleys), important features defining the topography and alpine style route planning. We consolidated 300 publicly available hiking routes (across as many passes) from various public GIS databases, blogs and other sources through accurately recorded GPS logs into Open Street Maps. Hikers can connect these individual trails into thousand-kilometre-long traverses across the entire Western Himalaya. We geo-referenced hundreds of maps using and identified one lakh kilometres of hiking routes, sufficient to explore over a lifetime! Legacy mapped trails are not always entirely accurate, requiring the need to explore and verify their precise location on the ground before adding them into OSM.

Due to climate change, migration to cities and construction of new roads, many remote settlements marked on the legacy maps are abandoned and have fallen in ruins. Connecting trails shown on the maps are no longer in use and have slowly faded away in the surrounding landscape. Some trails destroyed by landslides or overgrown by the forest are no longer repaired. We therefore need to explore and verify the present existence of digitized map routes on the ground before mapping them into OSM.

During my recent winter exploration of Uttarakhand, I explored 2000 km (just 2.5%!) of the above digitized trails. Those found to be still in use were accurately GPS recorded and added to Open Street Maps to be shared with the international hiking community. Any newly discovered hamlets, passes, shelters, mandirs, etc. were added to OSM. My objective is to continue full-time exploration and mapping of the entire Western Himalaya in the coming decades enabling like minded alpine style hikers across the world to discover

its magnificent natural beauty and conserve the heritage network of ancient paths, pilgrim and migration routes across the high passes for future generations.

More info, training and webinars on mapping and navigation can be found on my blog ultrajourneys.org

Summary

The author, in this illuminating article, explains various mapping systems and how they can be used as well as improved upon by mountain hikers and climbers. He plans to continue to map the Western Himalaya, so this is work in progress!

 

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