CASE STUDY

With the help of cutting-edge surveying technology, the Nepal Survey Department measured the height of Sagarmatha, or the Mount Everest, and will soon reveal how high the world’s highest mountain is.

The 2015 earthquake of 7.8 magnitude in Nepal not only claimed around 9,000 lives and injured over 22,000, it also raised speculation about the height of the Mount Everest, known as Sagarmatha (head of the sky) in Nepalese, as scientists believed that the world’s highest mountain may have shrunk slightly. To put to rest such speculations, the Nepal Survey Department decided to go ahead with the measurement of the Everest. “Nepal hadn’t done anything like that before, and so we thought why not do it now? But we required high-end technology, and Trimble provided that to us,” recalls Ganesh Prasad Bhatta, Executive Director of Land Management Training Center and former Director General of Nepal Survey Department.

“We are the national mapping agency of Nepal and so this is a very important project for us as it will go on to enhance our overall capacity. Countries have measured the Everest in the past, but this is the first time that Nepal has done it. The conclusion of the project will be a proud moment for us,” feels Prakash Joshi, Director General of Nepal Survey Department. The most commonly accepted figure for the Everest’s height is 29,029 feet, a measurement provided by the Survey of India in 1954.

Devising methodology

After devising a detailed internal methodology based on GNSS surveying, gravity surveying, precise levelling and trigonometric levelling, the department started the project (field work) early in 2018. “Towards the end of 2017, we organized an international workshop, which was attended by experts from the US, Europe, New Zealand, India and China. The sole objective of the event was to showcase our methodology to the world,” says Susheel Dangol, Chief Survey Officer and Coordinator of The Mount Everest Height Measurement Program.

Technological edge

It was during this workshop that the department contacted Trimble, which readily agreed to offer its cutting-edge surveying solutions that made a task as mammoth as surveying the Everest possible. “Trimble is proud to be associated with the Nepal Survey Department for this project to measure Sagarmatha. This is one of the most prestigious projects for us in the region. We recommended the department a few of our selected products such as the R10 integrated GNSS receiver, R9S as the base station to provide correction services to R10, robotic total stations and the Trimble Business Center (TBC) survey CAD software,” says Amit Saxena, Regional Sales Manager, Geospatial, SAARC Region at Trimble.

Thorough process

Apart from carrying out a GNSS survey on the top of the Everest for nearly 75 minutes, the department conducted a similar survey at 300 stations, gravity survey at 300 stations, 248km of precise levelling starting from the IndiaNepal boundary to various stations, and trigonometric levelling at 12 stations. “The R10 came in really handy because of three reasons: it was easy to carry, had antenna and receiver built into the device and had a long battery backup,” points out Dangol. “Some of the other major advantages of using the R10 receiver are that its HD GNSS technology helps in precise data capture and 360-degree satellite tracking enables surveyors to track the points quickly,” explains Saxena. R10 makes the collection of more accurate data faster and easier. Built with powerful technologies integrated into a sleek design, the unique system provides surveyors with a powerful way to increase data collection productivity in every project.

Before the project was started, Trimble trained over 30 survey department staff in advanced surveying techniques. High-end training was also given to the team leaders to ensure that they do not face difficulties during the expedition. “At the stage of precise levelling, the seven-member survey department project team used Trimble S9 robotic total station,” says Saxena.

After devising a detailed internal methodology based on GNSS surveying, gravity surveying, precise levelling and trigonometric levelling, the department started the field work early in 2018

The Trimble R10 (in picture) came in handy because it was easy to carry, had antenna and receiver built into the device and had a long battery backup

The Nepal Survey Department used multiple high-end Trimble products such as the R9S (in picture) to complete the Everest measurement project

Boost to data processing

Beating the odds, the expedition team completed the data collection process by December 2019. The survey department is now processing the data using TBC and is likely to come back with the exact height of the Everest in the next few months. “This will act as a benchmark for several other projects in the region. Considering the time, resources and the environment, this will turn out to be a project of its kind,” emphasizes Saxena. Among other things, TBC offers customizable templates, simplified selection tools and automated plotting functionality. The software allows its user to manage, process and create customer deliverables for all survey tasks with just one software package.

It was an experience of a lifetime, if not a life-altering experience, for the team members. “As you climb up, the wind speed is a problem. So is lack of appetite and risk of falling ill. While we were coming back after collecting data, I ran out of oxygen and was unconscious for almost five minutes. If a Sherpa hadn’t come to my aid, I would probably not have made it back alive. At the end of the expedition, though, I realized that it was worth risking my life,” recalls Rabin Karki, Survey Officer and a member of the expedition team. N

ow that the data collection is done, there is a sense of pride and excitement in the survey department. “We will be coming back with the numbers soon. For now, I would like to thank Trimble for providing us its technology and cooperating with us at every stage of the project,” says Prakash Joshi.