Great Arcs!

GREAT ARCS!

The Gloden ARC Expedition (1802-43)

All they wanted to do was mark an arc across India to prove their point. Little did these nineteenth century adventurers realise that their mammoth journey would revolutionise the future of geography in India.

What's the shape of the earth? Is it a sphere or a spheroid? All you have to do today to answer this question is refer to an encyclopedia or surf the Internet. However, more than 200 years ago, this was a tough nut to crack and even if you pointed to the latter, there wasn’t enough conclusive proof. Enter Colonel William Lambton, a British surveyor. It was the year 1802 and the country was our very own India.

Lambton began one of the greatest journeys ever undertaken in scientific history just to answer the above question. It was a journey that spanned 41 years, through the length and breadth of colonial India, in which thousands of lives were lost and which resulted in the comprehensive mapping of India and the revelation that the Himalayas, and not the Andes, were the tallest mountain range in the world.

We’re talking about the Great Arc experiment, also called the Great Trigonometrical Survey of India (GTS), which became possible thanks to the passion of two men — Lambton and Colonel George Everest, after whom Mt Everest was named — and their merry band of followers.

But wat is an ARC?

Now, an arc is part of a latitude or longitude that has been accurately measured physically on the ground and mapped. Lambert knew that if he determined the length of an arc along a chosen longitude at a one-degree latitude separation, then the length of that arc would be less near the equatorial latitudes than at the poles if the Earth were a spheroid. The bigger the arc, the more the accurate findings.

Earth's like an Orange...

..because of its spinning motion, it bulges at the middle and flattens at the ends (like an orange) to become a “spheroid”.

Triangles ot the Rescue

So Lambton employed the technique of triangulation to achieve his goal. In triangulation, you have to identify three visible reference points at a height as the corners of a triangle. Knowing the exact distance between two of these points, and then measuring the angles made at each by the respective lines of sight with the third reference point, the distance and position of the third point can be deduced by trigonometry.

One of the sides of this triangle can now serve as the baseline for a second triangle that will include a new reference point. Then that triangle could lead to another triangle and so on. Lambert decided to make a chain of such triangles all across India! The spinal column of this triangular skeleton was the Great Arc, which not only settled the spheroid debate, but laid the foundations for a comprehensive map of the country.

Wars, floods and dysentry

Lambton and his troupe of intrepid surveyors equipped with carriages, palanquins, tents and a massive half-tonne theodolite (an instrument to measure the angles of the triangles) began their gigantic quest on April 10, 1802, with the first baseline measurement between St Thomas Mount in Madras and a spot 7.5 km to its south. That measurement alone took 57 days!

The total north-south distance of 2,575 km was the longest measurement of the earth's surface ever attempted. The average length of a side of subsequent triangulations was 50 kms, the maximum being about 100 kms! Imagine doing this in nineteenth century India without any of the modern-day facilities. Trees and houses had to be cleared to get the line of sight right. Sometimes whole villages had to be razed.

Then there were malarial fevers, dysentery, floods, extreme weathers, treacherous hills, thick jungles and swamps, dacoity, snakebites and even battles. Plodding through nineteenth century India through all that must have been a Herculean task. And all the observations had to be done on top of tall structures like the tops of hills and temple gopurams. When these weren’t present, 30-metre high bamboo structures had to be erected.

Lambton and Everest

In 1818, George Everest joined Lambton, and together they convinced a sceptical British government that the project should go on and parleyed with local kings to allow them to pass through their land. If Lambton went on relentlessly despite fever and dysentery, Everest fought through his paralysis.

Then at the age of 70 in 1823, Lambton died before he could fulfill his dream in a place called Hinganghat on his way to Nagpur. He is still lies buried there today in an anonymous grave. The mantle fell on Everest's shoulders, who proved an able successor.

He conceived covering the length and breadth of the country by a 'gridiron' of triangular chains (see picture), as against a network of triangulations as conceived by Lambton. He took the survey to the foothills of the Himalayas in 1841. Add another two years for computation and the GTS was completed in 1843.

Changing our World

Lambton and Everest’s hard work continues to benefit us even today. The GTS is the foundation of all topographical surveys. All subsequent technological achievements in this field can be traced back to this. Accurate map details are a boon for those involved in developmental and infrastructure activities.

Even the entire network of roads, rail and telecommunications in the country is intricately linked with the topography through which these networks must go through. The GTS data has also aided fields such as astronomy, geophysics, seismo-tectonics, revenue, contribution to war and natural disaster relief measures and even socio-economic development!

Col Everest never saw Mt Everest. His successor, Surveyor-General Andrew Scott Waugh, observed and discovered the world's highest peak in 1852.

Assisted by the survey's chief computer, Radhanath Sickdhar, its height was determined to be 8,840 metres (8848m is now the accepted height). Waugh named it after his predecessor for his contribution to the Great Arc Expedition.

The survey showed that the Himalayas were the highest mountain range in the world

We’ve come a long way from the time it was thought that the Earth was a flat disc supported on an infinity of tortoises. And the future looks much more promising. A peek into the past.

FROM DICS TO SPHEROIDS

The earliest evidence of mapping comes from West Asia. Ancient Babylonian clay tablets depict the earth as a flat circular disk. The Egyptians and Mesopotamians after that tried to represent their world in the form of figures. Early Eskimos carved ivory coastal maps and the Incas built relief maps of stone and clay.

But as early as 1000 BC, the Chinese were the most advanced, accurate and detailed mapmakers in the world. They used their maps to administer their empire, but showed little interest in making world maps, even though they had knowledge about the world outside China.

What's the shape of the Earth?

For that, it was important to know the shape of the Earth.
The Greek thinkers were the most progressive with respect to that. First, Thales proposed that the Earth was a disc on the ocean. Later, Anaximander modified it to a cylinder, with the land on its curved surface. Finally, Pythagoras said that the Earth might be a sphere due to its geometrical perfection. Aristotle backed this by observation, though this view was not accepted by most of the world till the fifteenth century. Eratosthenes, a librarian of Alexandria, first used meridians (longitudes) and parallels (latitudes) to locate places in relationship to each other in the known world.

Ptolemy knew it ages ago

In 150 AD, Ptolemy compiled known astronomical data and created the first known projection of the known, spherical world, onto a plane. This was the beginning of scientific cartography. His coordinate systems are still in use today. In spite of his errors (that the sun revolved around the earth, and his calculation of the earth as 3/4th its present known size), he was far ahead of his time.

The dark age of maps

However soon after Europe entered the dark ages of
mapmaking as the knowledge of Greek thinkers was lost.
The view of the world was shaped by theological concerns and lack of contact with other places. The most interesting maps that came after that were the T-O maps. That’s because they were shaped in an “O” and divided by a “T. These proved to be the main world maps for centuries.

An ancient Babylonian clay tablet depicting the Earth as being a flat circular disk.

In this T-O map the "O" represents the known universe which is divided by a "T" into the three known continents of the time: Europe, Asia, Africa. The map had a strong religious slant and the centre of the world was Jerusalem and it was thought that paradise was beyond Asia!

But still, during this period, itineraries and route maps were
published for crusaders and pilgrims. In contrast, Arab maps advanced the earlier Greek practices. Al-Idrisi designed a still famous world map. The ideas of the Greeks and Ptolemy are preserved in Arabic translation.

But eventually, due to trade and contacts these works start to re-enter Europe. The Book of Roger, commissioned by a Norman king in Sicily in the 12 century, had maps and
a geography based on Ptolemy. Additional information,
probably based on trade in the East was used to update the
Ptolemaic maps.

For various reasons Europe starts to look at the world in
a different way. In addition to a willingness to accept some
of the Classical ideas now becoming available, there is
heightened interest in the seafaring trade to Asia.

World view of Greek philosopher Strabo. The map represented the sum total of cartographic knowledge before the Christian Era.

After the Dark Ages, cartographers managed to portray the Earth's spherical surface on paper. Shown above is one such map of the world.

Charting maps back on course

In the 13th Century, mariners began to realize that maps would be helpful and began keeping detailed records of their voyages that landbased mapmakers used to create the first nautical charts called Portolan Charts. The charts, created on sheepskin or goatskin, were rare and very expensive, often kept secret so that competing mariners would not have access to this knowledge. What they lacked in accuracy they made up for in beauty.

Lands and ports on the chart were highly decorated. The size of the lands on the chart was more a reflection of their importance to trade routes than their actual geographical size. The charts did not have latitude or longitude lines but did have compass roses indicating bearings between major ports. They were, of course, not very accurate because the ability to measure distances at sea had not yet developed, nor was there an accurate method to portray the spherical surface of the earth on a flat piece of material.

Mercator's colonial projection

In the 16th Century, Mercator created a map which was of great use to mariners since straight lines on the projection represent lines of constant compass bearing which are perfect for 'true' direction. However, this map has often been termed the 'colonial power map' because it makes Europe look a lot bigger then it really is. It is actually a poor projection because of its rectangular qualities and because the sizes of the countries are not accurate.

Newton's here too!

In the 17th Century, Newton said that due to its spinning motion, the earth bulges at the equator and flattens at the poles. He concluded that the earth is not a true sphere, but a spheroid. In the 19th Century, Europeans used the metric system, which proved to be a simpler and more universal language for map scaling. The Greenwich prime meridian was established.

Aand today...

In today’s world, computers, electronic distance-measuring instruments, sophisticated navigation systems, aerial photos and satellites have transformed cartography into geomatics, which includes Geographical Information Systems (GIS), Global Positioning Systems (GPS) and remote sensing.

These Smart maps can take Layers and Layers of Inormation

WITH A GIS YOU CAN

… add power to a conventional map
… understand a geographical problem better
… make better decisions
… manage information better
… manage resources better

While yesterday’s mapmaking concentrated on just Where a place was, today’s Geographical Information System is helping planners and analysts decide How and Who could get to that place in the best fashion, What to do with the problems of that place, Which way to go about solving those problems and maybe even in some cases When to do it.

But what exactly is a GIS?

Simply put, a GIS combines layers and layers of information about a place and puts them on a single map, so a problem can be viewed in a number of ways and unique solutions found. GIS software links geographic information (where things are) with descriptive information (what things are). This data can then be visualised, compared, measured, and analysed.

Now, how does that help?

The difference between a map and GIS is “seeing” and “understanding”. The human mind is good at recognising patterns. When you look at data in a long table of rows and columns, you’ll find it difficult to comprehend and connect. On the other hand, when this is presented as a map, it is not only more aesthetic, but helps you make connections and draw conclusions that you never saw before.

In today’s world, there is an overflow of information. We require more accurate, reliable and timely information and better tools to manage this and that’s where GIS scores over conventional mapping. GIS software tools are excellent for manipulating geographic information.

What can you put on a GIS map?

Everything you want. Population demographics, health statistics, utility and transportation networks, flood protection zones, animal migration routes, crime patterns, even historical battlefields, sales and marketing trends, disaster destruction areas, telecom, infrastructure, defence, healthcare — you name it. And the beauty of it all is you can choose which layer (information/statistic) you want and how many of them you want to put. As a GIS expert puts it, “The potential of GIS is limited only by the imagination of the user.”

Does GIS affect me?

Yes it does, in more ways than you think. All over the world, the complex infrastructure of telephone and electricity lines, water supply and irrigation systems, sewage lines are managed through GIS. Governments and defence planners rely on complex and exhaustive GIS databanks and so do emergency response teams.

How Did It All Begin?

In 1959, Waldo Tobler outlined a simple model called MIMO (map in-map out) for applying the computer to cartography. With that began geocoding, data capture, data analysis and display, all the standard elements of today’s GIS software. But the father of GIS is Roger F Tomlinson. In the 1950s and early 1960s, the Canadian government’s need to manage and plan the utilization of natural resources led to the development of the Canada Geographic Information Systems (CGIS) spearheaded by Tomlinson. It is one of the earliest successful GIS programs and is a large-scale system operating even today.

The Environmental Systems Research Institute's ArcView software released in 1982 was the first product that gave nonGIS users access to GIS databases. Today GIS is a flourishing and fast-growing multi-billion dollar industry that is changing the way we are looking at our world.

The old adage "Better information leads to better decisions" is true for GIS

The Global Positioning System (GPS) can show you your precise location on the Earth at any point in time. There are 24 GPS satellites in orbit that are continuously monitored by ground stations worldwide. The satellites transmit signals that can be detected by anyone with a GPS receiver.

GPS receivers can be hand carried or installed on aircraft, ships, tanks, submarines, cars, and trucks. The typical hand-held receiver is about the size of a cellular telephone. This technology is playing a role in the environment too. GPS-equipped balloons are monitoring holes in the ozone layer and air quality is being monitored using GPS receivers.

Buoys tracking major oil spills transmit data using GPS. During construction of the tunnel under the English Channel, British and French crews started digging from opposite ends. They relied on GPS receivers outside the tunnel to check their positions along the way and to make sure they met exactly in the middle.

In the future, every car on the road will have GPS receiver with a monitor. The screen will show your location and a map of the roads around you. Already, vehicle tracking is one of the fastest-growing GPS applications. GPS-equipped fleet vehicles, public transportation systems, delivery trucks, and courier services use receivers to monitor their locations at all times.

"If a student today decides to dump geography, it is because of his teachers. It is their job to make the subject more interesting and likable," says Dr. Prithvish Nag, Surveyor General of India

“We map every inch of the country"

GT: What are the activities of the Survey of India?
A: Right now we are digitizing all the maps we have, updating data through GIS, GPS and remote sensing, introducing Airborne Laser Terrain Mappers for more accurate mapping and expanding the existing infrastructure for a national spatial databank.

GT: Does all this have any relevance for sustainable development?
A: Sustainable development requires an updated information database. That's what GIS and GPS technologies are providing. The major subject areas it is very useful in are geology, petroleum, forestry, water and land resources.

GT: What are you doing to introduce GIS in schools?
A: The Survey Of India has initiated "mapping the neighborhood" with school students to introduce the concept of spatial information and mapping. The students learn how to prepare maps.

GT: What is your advice to students who are interested in Geography?
A: The students should get an exposure to computers at an early stage. Survey and mapping of data today requires voluminous data collection and correlation of that data aerially to the position on the ground with calculations, which is possible with the help of computers. Geography will help you to understand and correlate one set of data with another. For example, you can compare land and population and interpret your solutions to some the problems existing in that region. But again, for all this, you require a good knowledge of computers.

GT: What's the status of the study of Geography in schools and universities?
A: Geography in the education system today lacks the key teachings of the digital mapping systems and technological details that are the focal point today for most of the careers in survey and mapping such as GIS, GPS and remote sensing. There is a regional, national and even a global focus. However, today's requirement is to teach a very local specific knowledge and application of the subject. The student is lost in just a national scale approach, whereas local scale operations would give him a better understanding of the fundamentals.

GT: Do think there are any drawbacks in the GIS, GPS technology etc?
A: No. I think it is very useful and there are no drawbacks in the technology apart from the data limitations of remote sensing. It is a very successful technology.

Fancy a career in GIS?

There are many options if you want to make a career out of GIS-related fields. According to Dr Prithvish Nag, there are openings in information technology, communications technology and geology related fields like mining and forestry. You can get a staring salary anywhere between Rs 10,000 and 15,000. There are also lots of openings abroad due to an active information data industry.

There are resource management jobs in government orga-nizations and UN jobs concerned with crop forecast and water management in many countries. However, feels Dr Nag, there is a gap between what is taught to the student in the Indian universities and what is required by the industry. The need of the hour is to make the subject more job-oriented and functional in character so that the student is empowered with better skills after he completes his education.

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Sustainable Technology Has Arrived!

Mankind is slowly realizing the power of GIS in managing our planet. Here's a glimpse of the Earth’s natural resources through this versatile technology.

No more Foggy Forestgs

GIS gives foresters the “big picture” about resources and lets them perform tasks such as developing long-term supply strategies and determining harvesting system options. Managing forests in today's ever-changing world is becoming an increasingly complex and demanding challenge. GIS provides foresters with powerful tools to do so.

Penetrating the Sea in 3D

GIS technology allows experts to see a large portion of the Earth that is underwater and make a 3-dimensional map of it. It even helps tracking the journey of whales and tuna to preserve species in threatened areas. Marine GIS is helping oceanography, hydrography, navigation and defence and managing the coastal shoreline.

Here come the HI-tech Farmers

GIS provides the analytical capabilities for a successful precision agriculture system. GIS lets farmers perform site-specific spatial analyses of agronomic data. The study of geographic features and the relationship between them can be applied to all agriculture sectors. By understanding better how features within the landscape interact, decision makers can optimise efficiency and improve economic returns.

Liberating Farmers

Karnataka’s GIS scheme Bhoomi has revolutionized the way farmers access their land records. Thousands of farmers can now get a copy of the Record of Rights, Tenancy and Crops from a computerized information kiosk without harassment and bribe. Karnataka has computerized 20 million records of land ownership of 6.7 million farmers in the state. Land record updates used to take 1-2 years and were also not open to public, inaccuracies crept in, ineffective. Bhoomi is a major land reform and other states are also looking into it.

Remembefr before you step on your bus...

Transportation professionals in cities like New York have already integrated road systems into their GIS software. This is helpful for tracking and routing of buses and cars, inventory tracking for government vehicles, route planning and analysis. Indian road
and rail systems are also getting GIS-savvy.

The miner's major help

GIS creates efficiency and productivity opportunities in all aspects of mineral exploration and mining. GIS enables geologists and mine operators to mine intelligently, efficiently, competitively, safely, and environmentally. GIS provides the framework to acquire, develop, and interpret the complex spatial data.

Making hospitals more Hospitable

GIS software is used extensively throughout the medical community to study epidemiology, look at health care facilities, and map any system that is visual or spatial (including inside a patient's body).

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