SURVEY OF INDIA THROUGH THE AGES

LT. GEN. S. M. CHADHA*

Civilisation
THE HISTORY OF surveying commences with the history of people and advances with the histories of countries and nations. To understand surveying efforts in India, we should have a glimpse of the land and its civilisation.

The Indus Valley civilisation, the oldest and first great civilisation known, had its beginning before 2500 B.C. and was fully developed between 700 and 600 B.C. Then came the Aryan civilisation, which spread from west of the Ganges valley by 500 B.C. The Indian subcontinent has since had many kingdoms which rose, merged and disintegrated from time to time. The chief of these were: the Mauryan dynasty which was established by Chandragupta in 320 B.C. and lasted up to 600 A.D. and the Mughal dynasty which came in 1524 A.D. and ruled up to 1857. The East India Company's first settlements came in the 17th century and established a formal system of government in Bengal in 1700. Thereafter, the mercantile company which came for trade established an empire ruled by Britain since 1858.

And India achieved its independence in the year 1947.

Indian Culture
The roots of Indian culture run deep. It took nearly the thousand years between 1500 and 500 B.C. merely to lay the foundations of Hinduism-generally called the Vedic Age. It gave us the most important of the four Vedas called the Rigveda - the others being the Yajurveda, Samveda and Atharvaveda, consisting of prayers and instructions for priests, spiritual ceremonies, etc. After 700 B.C. came the Upanishads which later inspired Jainism and Buddhism and which probed into the nature of the universe and human soul and relations of each to the other. In the 6th century B.C. India gave birth to Gautam Buddha whose teachings and wisdom spread throughout southeast Asia.

*Text of the talk delivered at the Royal Geographical Society on 8 November 1990, on the eve of Sir George Everest Bicentenary celebration by the Surveyor General of India.

Surveys up to the 18th Century
The art, culture and kingdoms of India could not have spread through centuries and countries without knowledge of its geography. In the Vedic literature of over 5000 years ago, the knowledge of land was presented In a graphical form which described the extent and shape of territories. The Brahmand Purana of 500 B.C. to 700 A.D. gives evidence of the art of modern map-making. The art of surveying and techniques of mensuration of areas are described in Sulva Sutra (science of mensuration) and in the Arth Shastra of Chanakya written in the 3rd century B.C. The golden age of Indian Renaissance in the 5th century saw the towering genius Arya Bhat who wrote Surya Siddhant and calculated the earth's circumference to be 25,080 miles - less than 200 miles off modern measurements of the equator. Chinese and Arab travellers and many adventurers also contributed to Indian geography. Sher Shah Suri and Todar Mai's revenue maps, based on regular land survey systems, were well known in the medieval period and continued to be in practice during the mid-eighteenth century.

Jantar Mantar
Even today, the six huge instruments in masonry built by Raja Sawai Jai Singh in the heart of New Delhi in 1724, attract tourists from all over the world. These were designed and built by him to study the movements of the sun, moon and planets. Such instruments were also built in Jaipur to measure, among other things, time and eclipses. Another observatory was built by him in Ujjain in 1723 to forecast eclipses and movements of the sun as well as indicate the correct time.

According to records, Rajaraja I of Tanjore (985-1011 A.D.) carried out careful surveys of the lands and cultivation. This shows that there must have been many other surveys of which no clear records have been preserved. However, information is available" of the surveys instituted by Akbar during the 16th century; measurements being made by a hempen rope which was replaced by a ' jarib' of bamboos joined by iron rings. Settlement operations included the measurement and classification of lands, and fixation of rates. Systematic surveys commenced in the 18th century.

India's Topography
The topography of the Indian subcontinent varies from the snow-covered Himalayan peaks of the world's highest mountains to the rich and fertile plains of the Ganges, with large undulating areas, thick jungles, deserts, mighty rivers, swamps and a long coastline. The area of independent India (i.e. 1.28 million sq. miles, more than that of western Europe) is largely inhabited by the descendants of migrants from across the Himalaya and, today, it consists of a-mixture of various races, cultures, languages and religions.

The major religious communities of the "834 million people of India are Hindus, Muslims, Christians, Sikhs, Jains, Buddhists and Parsees speaking 15 officially - recognised languages and several hundred dialects. Such is the very rich culture and heritage of the nation, that is India.

And this is the land that the Survey of India surveys.

THE SURVEY OF INDIA TODAY
The Survey of India, fondly called the Department by its members, is organised into 10 regional Circles and 8 specialised Circles / Directorates. Each regional Circle is responsible for all topographical and developmental surveys of a State or group of small States. The specialised Directorates are the Geodetic and Research Branch, Map Publication Directorate, Directorate of Survey (Air), Survey Training Institute, Research & Development Directorate, Modern Cartographic Centre, Digital Mapping Centre and the Flood Plain Zoning Surveys. The manpower resource consists of over 7000 technical personnel. The Survey Training Institute runs about 45 courses a year - training about 600 officers. Apart from the basic, refresher and specialised courses, it runs advanced courses in photogrammetry, geodesy and cartography. This year, we have started a one-year advanced course in Integrated Digital Map Production and Geographical Information Sytems. We have about 60 field units, 14 photogrammetric units, 17 drawing offices, 5 printing groups and 23 other special units.

Apart from geodetic, topographical and geophysical surveys, the Department meets the survey needs of all developmental projects amounting to more than a hundred a year. Scientific projects like the study of seismotectonics of the Himalaya and many others are undertaken independently or in collaboration with other organisations.

The Survey of India' has covered the whole country by 1:50,000 rigorous metric surveys in about 5000 sheets. This is a feather in its cap since many large countries are yet to fully cover their areas on this or larger scales. About 30% of India has also been covered by 1:25,000 surveys.

The Department has met the challenges of surveying the indomitable Himalaya, blazing deserts and disease-and animal - infested jungles. The Department is continuously striving to keep abreast of modern technology and has successfully entered the era of Digital Mapping and Geographic Information Systems.

This is the edifice built on solid foundations, long history, strong traditions and deep roots.

1767-1800:THE ROOTS
The Survey of India traces its birth to the appointment of Major James Rennell as Surveyor General of Bengal, by Lord Robert Clive and his council, on the first of January 1767. He placed all available surveyors under Major Rennell's orders, amongst them being the Frenchman Claud Martin, who later became famous as the founder of the La Martiniere Schools.

By 1773, Rennell completed surveys of the possessions before relinquishing the post of Surveyor General in 1777. Rennell surveyed Bengal and Bihar, an area of over 1500 sq. miles, producing a continuous and uniform set of maps. The surveys, however, were far from complete or accurate in detail but were sufficient to meet the needs of the time. Rennell continued his interest in England, and his first Map of Hindoostan reached India in 1783.

The early history of surveys in India followed the East India Company's expanding areas of influence and conquest.

The next Surveyor General, Thomas Call, like many others who followed him, undertook the task of compiling an atlas embracing the whole of India. On the initiative of John Tringle, who surveyed routes with great enthusiasm, a military 'Corps of Guides' was established. This Corps also contributed largely to the surveys of the Madras Presidency for the next 30 years.

It was in 1787 that Michael Topping, a marine officer, broke away from the eternal method of Perambulator Traverse and ran a 300-mile line of triangles along the coast from Madras to Palk Strait. It was he who built a permanent astronomical observatory in Madras in 1793 and founded the first surveying school in 1794.

In 1796 and 1810, the Presidencies of Bombay and Madras got their own Surveyors General with the appointment of Lt Gen. Charles Reynolds and Col Colin Mackenzie as the respective Surveyors General. It was on the first of May 1815 that the Directors, finding it wasteful to maintain three separate and independent Surveyors General, appointed Mackenzie as the Surveyor General of India.

The credit of the first surveys of the Brahmaputra in Assam, in 1794, and that of the Irrawady river in Burma go to Thomas Wood. The mission also collected interesting information about people, tribes and general geography of Assam and Burma, about which nothing whatever had been known before.

India was one of the earliest countries to establish a regular government survey organisation and to commence systematic surveys - a few years before even the Ordnance Survey of UK.

1800-1843: SCIENTIFIC APPROACH - SOLID FOUNDATIONS
Lambton
It was very fortunate that a man of the genius and resolution of Lambton was in the subcontinent to lay the foundation of the 'Great Trignometrical Survey of India' a few years before similar projects were undertaken by France and England.

In November 1799, he put forward his proposal for a Mathematical and Geographical Survey that should extend right across the Peninsula from sea to sea, controlled by astronomical observations, carried out on scientific principles, capable of extension in any direction and to any distance. He started his work from Madras where, in early 1802, he measured the famous base line at Saint Thomas'. Mount as a start for his triangulation, north and south through Carnatic India and across the Peninsula, with his famous 36-inch great theodolite. He completed a meridional arc from Cuddalore to Madras observing latitude at both ends and obtaining a value for the length of a degree that was essential for his scientific work. By 1815, he had nearly covered the whole Peninsula south of the river Kistna (Krishna) with a network of triangulations braced by main cross belts. To him goes the distinction of measuring the longest geodetic arc closest to the equator, from Cape Comorin to the 18° parallel.

George Everest
In 1806, a subaltern came to India at the tender age of sixteen. He was none other than Lieutenant George Everest, whose birth bicentenary we are celebrating. He joined Lambton in 1818. Lambton died at work on 20 January 1823, at Hinganghat at the age of 70, Gen Walker recognising his work, wrote in 1870, 'of all Col Lambton's contributions to geodesy, the most important are his measurements of meridional arcs, the results of which have been employed up to the present time, in combination with those of other parts of the globe, in all investigations of the figure of the earth.

Lambton s mantle fell on the worthy shoulders of George Everest. Everest felt the need for basing the surveys on a rigid reference framework. This raised the problem of finding a suitable reference spheroid to fit the shape of the earth's gravity equi- potential surface for India and the adjacent countries. Everest realised that the Indian subcontinent was too large for basing surveys on an osculating sphere, leave alone a tangent or secant plane. Everest, therefore, started his control work from Kalianpur in Madhya Pradesh, more or less in the centre of India. Here, he made astronomical observations and treated the astronomical latitude, longitude and the plumbline at that place as error-free. With Kalianpur as the centre, he conceived covering the length and breadth of India by a gridiron of triangular chains, as opposed to the network of triangles conceived by Lambton. He brought to surveying greater accuracy and rigorous observational procedures besides devising and refining the instruments. He introduced the observation of astronomical azimuths from pairs of circumpolar stars, ray traces for long lines, etc. His redesigned 36-inch great theodolite is famous today. He replaced the chain with Colby's base-line apparatus and 10-foot compensation bars, with which he measured various bases. He completed the great meridional arc from Cape Comorin to Banog in the first Himalaya, near Mussoorie, a length of 2400 km. Everest made the government agree to the revision of Lambton's work, based on more accurate instruments and the procedures as laid down by him. Later, in 1830, he was appointed as the Surveyor General of India but, much against the wishes of the then government, he continued to devote much time to the Great Meridional Arc. This was completed by him in 1841 and he utilised the last 2 years of his service in its computations and adjustments. The work and norms laid down by Everest have stood the test of time. The Everest Spheroid, evolved by him in the year 1830, is not only still being used by India but also by Pakistan, Nepal, Burma, Sri Lanka, Bangladesh, Bhutan and other south-east Asian countries.

We can only grasp the significance of his monumental work if we can visualise India of the early nineteenth century - without communications and full of jungles, wild animals, robbers and disease. The average length of a side of the triangulation was about 31 miles, the maximum being about 62 miles. One cannot imagine how such long-distance observations were planned, laid down on the ground, line of sight cleared of all trees and sometimes even houses, and how big rivers and swamps were crossed. Everest, devoted to his work, did all this despite his partial paralysis and bad health.

Based on his conceptualization, the gridiron network today covers the entire country and forms a solid foundation for accurate surveys and mapping for defence, development and efficient administration.

It was with the help of this gridiron network that the highest peak of the world was observed and discovered in 1852 and its height declared as 29,002 ft-I.e. about 8840 metres. After fresh observations and computations, the Survey of India declared Its height In 1954 as 8848 metres. In 1975, the Chinese put a metallic beacon on Everest and observed It from 9 stations. They also carried out sufficient astronomical and gravlmetrical measurements, the co-efficient of refraction was reliably determined and the final result of the determination was declared as 8848.13 + 0.35 metres.

Sir Thomas Holdick concluded In the Standard of January 24, 1905, that 'It was officers of'the Survey of India who placed his name just ntar the stars, than that of any othir lover of eternal glory of the mountains and let It stay In witness to the faithful work not of one man but scores of men.' Everest was the first from amongst the eight Surveyors General of India to be k,nlghted.

The Great Instrument Repairer
Mention must be made of Mohsin Husain, the great instrument repairer. In recognising his work, Everest writes that, without his valuable aid, it would have been utterly out of his power to carry out various projects for remodelling the instruments, comparing the chains and standard bars, and removing radical defects in the reverberatory lamps. Hussain's crowning triumph was his successful division of the horizontal circles of two astronomical instruments during 1839 - a task which Barrow, the mathematical instrument maker had firmly refused to touch. In spite of the best efforts and recommendations of Everest, however, Mohsin was not promoted but his salary was raised to Rs. 250 per month. Nevertheless, Everest did not give up and got him a promotion and title in September 1843.

Other Survey Efforts up to 1843
Between 1808 and 1810, the scare and threat of Napoleon to invade India led to several political missions and surveyors to Sindh, Lahore, Peshawar and Persia. The frontiers of Gujarat were also surveyed on priority as a precaution against Napoleon's invasion.

A mention may also be made of the 'Military Institution' founded at the end of 1804 for the education of selected military cadets in mathematics, drawing and military fortifications and also, for several months each year, in field survey, triangulation and planetabllng a fresh area every year. The institution was closed in 1860 by which time It had completed nearly 15,000 sq miles of Arcot and Chitoor. Another expedient, the monthly survey allowance granted to inexperienced regimental officers, produced only a mass of problematic route surveys. In 1807, due to paucity of funds, Surveyor General Colebrooke took to the field himself and surveyed Rohilkhand.

Survey work on strict scientific lines reduced productivity. Therefore, in 1833, Increase In annual output was ordered by cutting professional work to the minimum, The work did get speeded up but resulted In little of long-term value for settlement or effective mapping of the country. The work had to be revised In later years.

During this period, 1800 to 1843, compilation of topographical surveys based on route surveys were gradually discarded and surveys based on geodetic control commenced. Solid foundations were laid by Lambton and Everest - both great geniuses in surveying.

1843 -19041 YEARS OF EXPLORATION AND CONSOLIDATION
Maj Gen Sir Andrew Scott Waugh holds the record of occupying the post of Surveyor General of India for the longest duration In history, from 1843 to 1861. It fellon him to extend the grid of triangles started by his illustrious predecessor, Sir George Everest, over Bengal, Bihar and Orissa with extensions towards the North-East Frontier and down the east coast. Later, the main triangulation was carried westward to the Indus and northwards through the mountain region of Kashmir. To link up, the Bombay triangulation was continued west and north.

These Surveys were not without problems and difficulties. The passage of the desert, 150 miles of sand hills, raised serious problems of supplies - including scanty wells that were too often over 300 ft. deep, brackish water, lack of building materials for towers, mirage and other vagaries of refraction. A surveyor commented 'a miserable country, only interesting for its physical deficiencies.'

Montgomerie started the Kashmir triangulation in 1855 from Jammu and extended it across the Pir Panjal to the Great Himalayan range, fixing the peaks of Nanga Parbat and K2. Many triangulation stations were established at heights of over 5800 m.

Mention may be made of Capt Godwin Austen who, by temperament and physique, was the ideal man for topographical surveys under the roughest conditions. His planetable survey of the glaciers of K2 and other peaks were notable pieces of work. Phillimore writes,'His work in the high Karakoram attracted particular attention and led to the unfortunate suggestion that his name be given to the peak that Montgomerie had discovered and had designated as K2, for which no local name had been found.' '

Radhanath Sickdhar2
Born Oct. 1813, he joined the Surveyor General's Office in December 1831 and rose to the rank of Chief Computer. He authored many technical publications and contributed to several others.- He assisted Thuillier and Smith in the preparation of the Manual of Surveying for India for which he was duly acknowledged in the preface to the first and second editions. However, this acknowledgement was omitted in the third edition of September 1875. Strong criticism in the local press was contributed by a retired and a serving officer. The serving officer was sharply reprimanded and reduced in seniority. Radhanath also published A set of tables for facilitating the computation of trignometrical survey and the projection of maps for India, based on formulae authorised by Everest and in some cases modified by Radhanath himself. During his spare time, he acquainted himself with the latest in English and French geodesy including Puissant's work of 1842. Waugh was always afraid of losing him to other departments, and had asked for a much higher salary for him, but the government considered Rs. 400 per month as sufficient remuneration.

1. A series of volumes of Historical Records of the Survey of India were published, collected and compiled by Colonel R. H. Phillimore. -Ed.

2. Phillimore uses this spelling. Others have spelt his name as 'Sikhdar' or 'Sikdar'. -Ed.

Radhanath was in charge of the computation section in Calcutta and was constantly consulted by Waugh regarding refraction and formulae for vertical angles. There is a controversy as to who first computed and discovered peak No. 15, the highest in the world, later named Everest. It is not clear whether the Chief Computer who made the calculations was Radhanath Sickdhar or John Hennessey. However, Phillimore felt that Radhanath had no share in it.3
Spirit Levelling
Gen Walker is known as the father of Indian levelling for the care, thought and execution of levelling practices in India.

Discrepancies were found in the heights brought out by triangulation from various connection with the sea level. It became clear that, except for hilly areas, more accurate values would have to be derived by spirit levelling. This was also felt necessary to control engineering and irrigation projects. A tidal station was established at Karachi and spirit levelling of precision was introduced as a part of the Great Trignometric Survey in 1858. It was Walker who introduced the system of simultaneous double levelling - each line being observed by two levellers working independently.

Gravity
George Everest felt the importance of gravity and pendulum operations while studying the effect of local attractions and the deflection due to the Himalaya on the measurement of the Great Arc. The pendulums obtained by him were not used. It was left to Capt Basevi and Capt Hennessey to start the pendulum observations at Dehra Dun in 1865. From 1866, Basevi carried the gravity series over the Great Meridional Arc from Dehra Dun to Cape Comorin. He died at work in Ladakh in July 1871. Archdeacon John Henry Prat, in Calcutta, devoted himself to calculations of the actual, amount of attractions of the Himalayan masses and the deflection or deviation of the vertical (plumb line). His major contribution was that the deflection calculated from the known distribution of mountain mass, was much greater than that actually observed; from which he deduced the theory of Isostasy. Thus, India, the birth place of the theory, contributed significantly to geophysical sciences.

3. For the opposite view see, 'Who Measured Everest?' by Bill Aitken in the Himalayan Club Newsletter 42, p. 43 and 'Radhanath Sikdar and the Highest Peak in the world', by Sambhu Nath Das in the Himalayan Mountaineering Journal Vol. XVII, p. 17. Also see letters by T. H. Braham (HCNL43, p. 49), and Sambhu Nath Das (HCNL44, p. 41). -Ed.

The Great Indian Explorers
The years 1865-1885 were most fruitful for Indian explorers who explored the uplands of Tibet, Mongolia and Central Asia under very severe and trying conditions.

Before 1864, the maps of this region were either blank or based on travellers' tales. Yarkand, though explored, was 160 km. out of position. Central Tibet was unknown and Lhasa's longitude was very doubtful. It was also not very well known whether the Tsangpo flowed into Burma or India. Indian explorers, inspired by professional spirit, mapped areas, traced the courses of rivers and discovered new people and their culture-trained as they were to take latitudes by sextant, directions by compass, heights by observing the temperature of boiling water and distances by accurately measured paces. Above all, they had to pass as simple travellers and friends of all carrying a rosary and a prayer wheel as any good Tibetan. There were many Indians who explored Tibet and the famous amongst them were Pundit Nain Singh, Pundit Kishan Singh, Kalian Singh, Hari Ram, Lala, Nem Singh, Kinthup, Rinzin Namgyal and Ugyen Gyatso.

Pundit Nain Singh
Nain Singh's first famous journey of 1200 miles from Kathmandu to Lhasa and then to Manasarovar in 1865-66 was a great feat. He brought back details of a map for the southeast trade route of Tibet and the Tsangpo's course of 200 km. This journey was recognised by the Royal Geographical Society which awarded Nain Singh a gold watch. His last and greatest journey was from Leh to Assam via Lhasa in 1873-75. This magnificent achievement yielded valuable geographical results.

On his way to Lhasa in 1865, he kept rotating the prayer wheel as befitting a devout Buddhist, not for charity, nor for charting a safe passage for his soul but as a contraption to store his observations. He took 31 observations of latitude and 30 of boiling point to determine height, laying down 4000 km of route survey.

Pundit Kishen Singh Milamwal
Pundit Kishan Singh was almost destined to gain greater fame than Nain Singh. His first important journey was undertaken in 1872, making a route survey from Shigatse, north of the Tsangpo, round the shores of the Tengri Nor reaching Lhasa from the north. He made many journeys but his last journey to Tibet and Mongolia from 1878 to 1882 was full of perseverance and adventure. In India, because of his long absence, hopes of his return were abandoned. After nearly 4 years, he made his way back home via the confines of China. He won great applause from the geographers of Europe and the Geographical Society of Italy.

Had the government considered the. great Indian explorers for knighthood, many would have mo"re than deserved it and added to the glory of the Survey of India.

Compilation - Engraving
Compilation, engraving and publication were done in London from material regularly sent from India. The work fell into arrears and, as a result of the Surveyor General's protests, the production of maps was transferred to India in 1869.

From about 1841, the work of the Government Lithographic Press at Calcutta was far from satisfactory. The machines and staff were effectively transferred to the Surveyor General in 1852. Some machines were constructed locally and others imported, and map printing came under departmental control.

The Survey of India printed the first postage stamps of India during 1854-55 on the stone litho proving press. In 15 months, over 47 million stamps were struck off; half-anna in blue, one-anna in red and four-anna in red and blue. Photolithography started in Calcutta in 1862. Zincography started at Dehra Dun in 1866 after a course of training at the Ordnance Survey, Southampton.

Magnetism
Magnetic observations were started during Everest's tenure by Capt Boilean in 1840 but kept in abeyance till 1896. The first determination of the various values - i.e. dip, declination and horizontal forces etc. - were made in 1901 with Survey of India pattern instruments. Magnetic observatories were also established during 1902-04.

Tides
The importance of the investigations of the laws of the tides of the Indian seas was strongly felt to be available to seamen and scientists. In 1834, the East India Company desired Everest to start tide observations. Though the earliest recorded tidal observations are those of James Kyd at the Hooghly river (1806-27) a breakthrough was made only in 1871-72 by Major B. R. Anjill of the Survey of India who introduced a self-registering tide gauge at Tuticorin and reduced the observations by simple harmonic analysis. Today, the Survey of India has tide gauges in 22 ports and publishes the tide tables of 44 ports from Aden to Singapore.

Security of Maps
It is interesting to note that the greatest importance was attached to the security of maps. There was a strict rule that surveyors should treat their work as secret and not pass on copies even to local officers, civil or military, without proper authority. It is presumed that this was, as Hodgson noted, because many public officers carry papers in their charge to England, especially maps which are put to sinister uses.4
Other Notable Events
During this era, the notable events were the start of the railways in 1853, the Geological Survey of India and electric telegraphy in 1851, and the Indian Meteorological Department in 1875. These, apart from increasing the demand for surveys, also competed for educated staff, all of which affected the Survey of India.

1905 -1946 : THE DIFFICULT YEARS
The Committee
Complaints were received from the military authorities that Survey of India maps were not modern, that the topographical surveys were progressing too slowly and revenue surveys were given too much prominence in the Department's programmes. This resulted, in 1905, in the convening of a committee of high civil, military and departmental officers as well as advisers from the ordnance survey to formulate a policy and programme to meet military as well as civil needs - except for revenue surveys which, from that time, became the responsibility of the provinces.

The policy and programme to cover India in 25 years with modern coloured and contoured maps was approved and put into effect by the government. Many maps were published on the new layout as devised by the Committee of 1905-06 with contours and with colours. These specifications more or less, continued for over 80 years. But far more weighty events elsewhere in the world changed the mandate of the Department.

The First World War
In August 1914, the Survey of India was in recess, completing records of the last field season and planning for the next, when the war broke out. Most of the Department's military officers and some civilian reservist officers were reverted to military duty. This left the Survey of India very short-handed and survey programmes were slowed down drastically. The necessity for comprehensive survey and mapping work in any major war and during the reconstruction period afterwards had not been recognised. As a consequence, suitable experienced personnel for military surveys could not be found easily. The need became intense when war reached Mesopotamia, a virtually unmapped country. A strong survey service was formed which functioned in Mesopotamia, Persia and Macedonia, surveying altogether nearly 180,000 sq. miles. This work was scientifically executecWand based on triangulation. Rapid reconnaissance of about 7000 sq. miles and route surveys of 2200 linear miles were also undertaken in Khurdistan, the Upper Euphrates, the Syrian desert, Persia and East Africa. Large-scale surveys of cantonments and principal cities were also carried out.

4. Alas the same policy still continues today, depriving mountaineers of all the maps of the Himalayan regions and other mountain areas. -Ed.

The Department can be justifiably proud of its achievements during the war. Its officers and staff completed many onerous tasks and won well-deserved laurels, at the cost of 57 lives.

It was during this period that the value of aerial photography was realised. It was used for large-scale surveys in Salonika and to deliver position maps based on the latest photographs. It was for the first time that the aerial photographs were used stereoscopically to draw and map contours.

1918-1939: THE DEPRESSION
It was recognised that, even in small wars, strong militarised survey and map-publication potential would be necessary with the fighting forces, and that make-shift arrangements are not the most effective way to lend survey support to the military.

The deployment of aircraft and use of aerial photographs for mapping, showed the necessity for research. After some experiments, the survey of the Irrawaddy delta was undertaken in 1922-23.

The Survey of India expanded and fresh recruitments were made. It is interesting to note that the Burma Survey Party manned by Survey of India personnel, continued to be under the technical control of the Surveyor General of India till the end of the Second World War.

Because of the world depression, the Survey of India started 'paid - for jobs for irrigation surveys, settlement surveys, etc. required by the provinces.

It was clear that there was no chance whatever of completing the modern survey programmes of India, though 35 years had elapsed.

By the end of 1938, rumours of war stirred up mobilisation plans, training, etc., in close collaboration with the artillery.

The Second World War
At the outset, the impact of the war was not seriously felt in India. The immediate results, however, were the curtailment of civil programmes, comprehensive and intense military training, improvement of war establishments and equipment tables, and mobilisation schemes coupled with expediting the five new rotary offset machines on order.

Because of increased commitments on the Survey of India, the Geographical Section General Staff headed by a Director of the Survey of India was raised in 1942. From there on, the Survey of India's responsibility to the army was through GSGS.

Another milestone was the establishment of a new map factory at Hathibarkala, Dehra Dun, designed to accommodate 8 to 10 printing machines. Map production was increased more than 25 times and the Survey of India's strength rose from 1400 to 2260. In 1943, the Geodetic Branch was split by the formation of a War Survey Research Institute. During the war years, the main problem of the Survey of India was quantity versus time. During this period, it churned out over 65 million maps.

Towards the end of and after second world war, the rehabilitation schemes for 2 million men of the Indian army together with demands for surveys for 'Grow More Food' projects engaged the Survey of India's potential.

The post-war sanctioned strength of the Department was seven circles and 24 parties as against four circles and 12 parties in 1939.

The two World Wars and a great depression in between were trying and difficult years for the Survey of India - but it emerged tempered and experienced.

1947-1965: INDEPENDENCE AND NEW CHALLENGES
After Independence, there was an upsurge of development all over the country which has continued till today. With planning for economic development, hundreds of schemes required survey data for scientific planning and execution. The Survey of India had to divert most of its potential for developmental projects, the normal topographical surveys being relegated to a secondary place.

Projects competed for survey potential and a Survey Priorities Committee had to be established in 1961 to prioritise the meagre potential of the Survey of India. Added to this was the fact that only about 60 per cent of the country was covered with rigorous surveys on the one-inch scale - the difficult areas of the high Himalaya, the north-east region and the deserts remained to be covered by accurate surveys. Based on the recommendations of the various committees to assess the total requirement of the surveys for developmental projects and utilization of natural resources, the Department was considerably expanded during the period 1961-66.

Threat on India's Northern Borders
During 1962 and thereafter, because of the threat on the northern borders, a new directorate was entrusted with the task of completing the mapping of the high hill areas within.the next 3-5 years. The task was immense, the terrain formidable and intricate, and it lacked communication. Every detachment was an expedition and many precious lives were lost.

The task of surveying the Himalaya could not have been completed successfully and within a reasonable time-frame, had the Department not kept pace with modern developments - especially photogrammetry.

1967-1990: IN PURSUIT OF EXCELLENCE GEODESY
Satellite geodesy was introduced in 1982 and many vectors have since been observed to strengthen the Indian geodetic network. Outlying islands have also been connected to the main land. The first phase of the primary and secondary triangulation network at a spacing of 4° (400 Km) apart was completed in 1956. About 30 per cent of the work of densification of the control network from the 4° to a 2° spacing, has been completed.

The second level net, consisting of 99 lines about 26,400 km., was completed by 1977 and Bombay port formed the basis of second adjustment. This revealed that the east coast MSL at Madras is higher by 1 foot than the west coast MSL at Mangalore, on the same latitude. The maximum permissible error between these two stations, 680 km apart, could only be 8 cm. The local MSL at Bombay is the lowest.

The levelling lines spacing of 200 km is planned to be reduced to 96 km apart and about 64 per cent of the work has been accomplished. Similarly, the gravity network is also being densified.

Sea Level Rise
The observations at a few tidal stations on the east and west coasts indicate a general rise in the sea level of the order of 7.8 to 9.0 cm per century. The highest, 4.06 mm/yr (SE± 1.8mm) at Kandla and Madras between 1954 and 1978, showed a negative trend of 1.18 mm/yr (SE±0.93 mm/yr). The average trend of the sea level rise of 1.0 mm/yr, agrees with the world findings.

Seismotectonics
Recent geodetic strain patterns studied in the northeastern region have revealed an anticlockwise rotation of 0.6 micro radian/yr and clockwise of 0.2. A displacement of more than 2 metres magnitude has been observed at one of the stations. The results are somewhat in agreement with the seismic data. A little east of this area, 8 BMs have revealed a vertical movement at the rate of 2.0 to 5.0 mm per year. The absolute change between 2 epochs observed at one of the BM is of the order of 44 cm.

Training
With the assistance of UNDP, a Survey Training Institute and a Pilot Map Production Plant were established at Hyderabad on modern lines during 1967. During 1990, apart from establishing a one-year advanced course in integrated digital map production systems and geographic information systems, the course syllabi and structure for all Survey Training Institute's courses are being reviewed and revised to meet the challenges of the new digital environment.

India Photo Interpretation Institute
A need was felt for advanced training facilities in the techniques of aerial photo interpretation in applied geology, mineral exploration, soil conservation, land use, forests and other disciplines. The offer made by the government of the Netherlands in 1964 was realised in May 1966 with the establishment of the Indian Photo Interpretation Institute at Dehra Dun for training interpretation specialists in the field of geology, forestry and soils. However, in 1976, the institute was transferred from the Survey of India to the National Remote Sensing Agency.

Topographic Mapping
With the completion of 1 :50,000 surveys covering the whole country, the Department now strives towards the completion of 1 : 25,000 surveys. However about 40 per cent of its resources continue to be deployed on developmental surveys.

Digital Cartography
Digital Cartography came to the Survey of India in 1982 with the establishment of the Automated Cartographic Cell under the R&D Directorate.

The Modern Cartographic Centre and the Digital Mapping Centre have been commissioned, tested and accepted. The main focus is on the generation of standard operating procedures and they are expected to be fully operational within the next few months. The Survey of India plans to decentralise data capture and verification, through PC and work station based small systems spread all over the country during the 8th five-year plan. This will help the Survey of India to achieve its ambition to digitise its entire 1 : 250,000 cartographic data in the next 4 to 5 years together with substantial data of the 1 : 50,000 scale.

A very large project of India's Ministry of Water Resources for the survey of flood plain zones is also being planned on modern systems.

Popularisation Programmes
To make the people more map conscious and more aware of the Indian cities, states and the country, the publication of four series of maps of high quality, has been launched. These are: the Tourist Map Series, covering all the major cities of the country; the Trekking Map Series; the State Map Series, each map covering one or more States; and the 'Discover India Series' under which themes of interest would be published like Motoring Map, Hill Ranges and Rivers, National Parks and Sanctuaries.

Quite a few maps in these series have been published and others are in the pipeline. With a strong distribution system, this will give a great boost to map use and awareness in India.

The future
The Department, built on solid foundations, strong traditions and deep roots, keeps striving to keep India among the best surveyed countries in the world, adopting the latest technologies to meet new challenges - always living up to its motto: A Setu Himachalarn:

SUMMARY

Tracing the history of Survey of India and its work in the Himalaya and elsewhere. This talk was in celebration of the birth bicentenary of Sir George Everest.

'From Setu to the Himalaya' (covering entire India). Setu: A bridge Rama had built on the southern tip of India to cross to Sri Lanka. -Ed.