FIRST SURVEY OF SARAWAK

Hauraki Plains Gazette, Volume 52, Issue 3294, 30 July 1943, Page 3

FIRST SURVEY OF SARAWAK

difficult task

PAEROA MAN EMPLOYED

LECTURE GIVEN IN LONDON

ROYAL GEOGRAPHICAL SOCIETY

The following interesting lecture, detailing the problems which had to be overcome in carryingout a survey of Sarawak, was delivered by Major D. L. Leach, R.E., in London recently at a meeting of The Royal Geographical Society. The lecture was later published in the society’s magazine, The Geographical Journal. Major Leach who is the son of Mr D. Leach of Paeroa, left New Zealand to assist to lay down the triangulation of Sarawak and after this work was completed was appointed resident officer at Sibu, in Sarawak.

Sarawak has an area of about 50,000' square miles with a coastline ef 450 miles. There are many rivers, some navigable in their lower reaches, large areas of coastal plain and swamp, a broken interior rising to high forested mountains on the boundary. There are no arterial roads or railways and therefore the areas of close settlement are found around the lower reaches of the large rivers. Isolated ipatch-es of native permanent cultivation extend from the closely settled areas into the interior. The map shows the location of the principal rubber, sago and pepper plantation areas as well as the districts from which come the natural products of the country. The population is about half a million, of whom one hundred thousand are Chinese, the remainder Malay and pagan races, and there were some three hundred and ninety Europeans including the staff of the oilfields.

Before 1920 there were only topographical sketches, mostly of rivers, made by the late. Dr. Charles Hose, and others; rough isolated surveys of various cultivations.; and sometimes small parcels of land alienated for short terms were described by rough measurements made by the local clerk or policeman. The nearest approach to a title survey was that made when the land was granted for a long term of years. Fairly accurate measurements of 'boundaries were then made and described in a diagram on the back of the grant, of which some thousands were issued. As these older boundaries were generally fairly well looked after and the issue of grants, kept pace more or less with the demand for land,' the adjoining description fitted together more or less over closely settled areas, but there was no survey control or cadastral system.

The years 1920-25 saw the beginning of a demand for land in small parcels that was to increase rapidly. They saw the beginning of survey with limited funds and means, sound enough in elementary principles, but suffering • from the lack of a longterm plan and standard policy. Accuracy varied in the same class of work and none of the minor triangulations or traverse control could be adapted to extensions. Topographical surveys during this time were traverses of some of the main'rivers by subtense or compass and rangefinder and a coastal traverse of perhaps the same accuracy. The only control was by isolated-astronomical fixes. This was useful for scales up to 1/150,000 but not for larger scales. By 1925 the survey had failed to keep pace with the alienation of land in small lots and with the rubber boom in full swing, the situation was rapidly becoming chaotic. The Survey Department was then separated from the Land Department and. placed under the direction of Mr N. A. Middlemass from the Federated Malay States. Plans were made for a triangulation of first or at least good secondary standard; for a subsidiary triangulation dependent on this, with hill sketching for maps on 1 inch to the mile; standard traverses to take the place of tertiary triangulation; theodolite control traverses round blocks of land parcels; and compass and chain surveys of individual lots., to form the basis of title. It was intended that.all these should be carried on together so far as finance and staff allowed. But much “cart before the horse” work had to be done, which, as all surveyors know, is more expensive in the long Tun. Scales were to be a mile to the inch for the cadastral and topo

graphical maps covering 25 square '■ miles, and 16 chains and 4 chains to i the inch for cadastral maps, making ■' respectively twenty-five and four hundred sheets for each of the inch maps. Town plans on the scale of one chain to the inch were all theodolate surveys. As for as resources permitted, theodolite control traverses were run round blocks of lots enclosing from 50 to 200 acres. At this time i there was a great shortage of unskilled labour owing to the boom in rubber, which reached its height in

1926. A coolie could earn far more in a few days tapping rubber than the survey could, pay a skilled demarca-' tor for a week. By 1930 the labour position had become much easier.

In order that the control traverses should fit into the projected triangulation and standard traverse network, these were orientated by basing the work on a local astronomical point and thus keeping the bearings to the meridian of reference. The co-ordin-ate positions of a block were of course only approximate.

By 1931 the triangulation was planned and the first base line was measured at Matang near Kuching in August of that year. Sarawak does not offer much ground for good base measurements. The coastal plain is more swamp than hard ground and the undulating country within has too many abrupt slopes and ravines. The major part of the Matang base wa's on an embankment road built over the swamp, to carry the Kuching water supply. The ground was fairly good over the greater part of its seven miles. One end was near sea level while the other had to run steeply up to 300 feet on a mountain side. Base extension was difficult. The measurements were made as usual with 100feet invar tapes in catenary or moveable tripods, and corrections for slope obtained by levelling between tripod heads, wijh collections for deformation of the catenary on the steep approach to the western terminal, of which the worst part was measured by a long steel tape one-sixteenth of an inch wide, weighing only 11b. for 330 feet. All field tapes were standardised daily in catenary at a testing station in Kuching. Wind was no trouble as vegetation afforded good shelter. Before the reconnaissance of the main triangulation could be begun, some of the more domestic problems had to be settled. In Sarawak communications have naturally grown up to meet the needs of local inhabitants. The numerous rivers are the highways of trading, the communications between one river system and another are poor. Native paths and tracks, often precipitous and always muddy and slippery in the wet season, vary from a made pathway three or four feet wide to an apology for a track that tried one’s temper when the weather was bad and the journey long. Once away from these inter-village tracks, one sometimes uses tracks made by pigs and very often cuts one’s way, which is not as tedious as it sounds in the “old jungle” as they call the forest which covers a great part of the country, but is to be avoided in secondary growth of only a few years. The older secondary growth is not so bad. One unloaded coolie leading can with judicious use of his parang keep the party in fair progress except in actual swamp. Here one may take advantage of pathways made by felling trees so that a more or less continuous line of trunks does duty as a road. There is seldom any handrail, and a slip means a nasty fall among the roots and spikes into the mud and slime of a swamp forest. Travelling by river may vary in one day from a pleasant trip in a comfortable motor launch to a precarious existence in a narrow dug-out canoe, where a sense of balance and the ability to sit in one position for hours is the secret of long life.

So, much thought had to be given to the outfit required to maintain a European officer and native party for long spells in the field in these conditions, and to enable him to move quickly when everything had to be carried in baskets on the backs of porters over steep country. Except for instruments, equipment had to be made from local resources. Fortunately the early work on the base line was near Kuching, and the equipment was designed by trial and erTor.

For spending nights away from villages most travellers in Sarawak rely on temporary shelters made from kajangs and jungle poles. A weather leaf, but they do not stand much moving or re-erection. For a long stay comfortable houses can be built with kajanks and jungle poles. A weatherproof bark, but needs no transport

but takes long to build. Temporary

shelters can be made from light poles and various kinds of palm leaf, but one’s comfort depends greatly on the locality. A tent seemed to be the answer, but all those made by professionals were far too heavy and cumbrous, especially after a wet night, so a tent of ridge-pole type, 8 feet by 6 feet, was made to measure by the local Chinese tailor from 6oz. khaki drill reinforced at the corners, which gave excellent service in all weathers, tropical downpours and blazing heat. No poles were carried. For clothes, bedding and books, containers of tinned steel or zinc made in convenient sizes for pack-loads, with a deep closefitting lid, not too big, to be placed conveniently upright in small boats. Camp beds, sometimes carried when river transport was used, -were useful when spending the night in a house with a wooden floor, but otherwise an unnecessary luxury. Jungle kit was a canvas ground sheet, a thin blanket for mattress, a small pillow, and a couple of light blankets bought in the bazaar for a Singapore dollar or so each.

Rice is the staple food of the country, with fern tops and fish caught with a jala-jala net, pig, deer and wild pigeons, with occasional chickens and eggs from villages. Some European foods were carried. All loads to be adapted for packing in the native carrying basket, the slabit, with a basketwork or wooden panel to fit the back and shoulders, the head straps made from the tough inner bark of a tree.

Reconnaissance for triangulation was in general difficult. All hills are covered in heavy forest, and it is useless to ‘fell much unless sure that the point is wanted. ■ The most successful plan if little was known about the country, was to make a preliminary journey by the easiest route along the line of the chain and get an approximate idea of the orgography by clearing lightly wooded low hills, near the line of march and intersecting the higher points from these stations wherever possible. Later most of the higher points would have to be visited and the rays proved by cutting a view on the bearing of each line. Clearing of the whole point, marking the station and erection of the beacon was carried out by a party under a native headman.

Travelling being so slow, a visit to these high points to prove rays was' very much a flying trip, and only the bare minimum of stores could be carried, the remainder being left below. It is surprising how.much attention has to be paid to this question of cutting down weight, and how little one really needs. Even on reconnaissance, and certainly for observing, one had to be on the top at the crack of dawn and •again for the hour or two before dark and one’s camp therefore had to be near the top. Often the water situation was acute, even in Sarawak; on one occasion all water had to be carried up over 2000 ft. One might spend all day clearing sight for the reconnaissance; then mist would cOme down for 24 hours. Climing trees to get a view was useful only if the mountain had a high, sharp peak, for nearby ridges and spurs generally carry much heavier and taller timber than the summit. These difficulties increased when dealing with hogback ridges of 500-1500 ft. near the coastal plain. Having decided on possible points, most of them were visited to prove rays. Often the highest point was located only after running clinometer or barometer traverses along a section of the ridge top. Excessive cutting to prove rays was sometimes avoided by ranging through the forest a line from the proposed trigpoint to where the fall of the mountain side gave a view of the distant point. Thirty-foot flagpoles lashed into the tops of trees were sometimes useful in base net and secondary trig reconnaissance. Preliminary heights were by barometer or better by vertical angles on 3in. theodolite. The information obtained during the primary reconnaissance was supplemented by visits to the area in which the secondary breakdown was. required after the primary points had been fixed. This reconnaissance was a good deal easier to carry out but sometimes became complicated owing to the fact that in a country not fully developed, the ideal distribution of a trig net conflicted with the ruling condition that “secondary trigs, are required, in or near areas of settlement.” The future use of trig, points was not to be lost sight of: it was the old problem of cost and present needs against the long term and ultimately cheaper, view. Clearing and Marking Stations

The need for the station having been established beyond doubt, the

whole hilltop was cleared of timber except on hogback ridges or in confused country with rounded hilltops. Here either a sectio nof the forest on the ridge was cleared or wiae lanes cut through. Clearings 1 were sometimes 10-12 acres for one trig, point, all heavy, close-growing timber. Some lines on the Marudi base net points were i-mile long and 60ft. wide. On a hill such as Buri, although it had a rounded top of considerable extent, it was more economical to clear the whole as many rays' met there. In this kind of general clearing the “driving” method can be used with effect. A section of forest on a slope is dealt with by only partly cutting all the trees except those at the head of the slope, which are cut and felled simultaneously against the remainder when the whole section comes to the ground with a continuous roar of cracking timber and crashing tree trunks. Great is l the excitement among the tree fellers when a successful drive takes place.

A selected few who start the drive, having got their trees “speaking” and ready to fall, stand ready to give the few final axe blows while the uppermost man, generally the head man of the village, is l ready to give the warning that brings the others scuttling to the top. As the drive begins one gets glimpses of the axemen dodging out of danger, their nearly naked brown bodies looking very frail amongst the big timber. Once the drive is properly under way a tremendous yelling and shouting* is set up to encourage the trees to fall. Tobacco and a rest is the reward of success. When a drive sticks there are dangerous moments and if shouting at the tree is l of no avail the most active man is sent in to chop at the critical point, to the accompaniment of much advice from the bystanders. He has not much time to get out again but we had no serious accidents in the whole course of the survey. The labour for this work was recruited from the nearest village. Of the fifteen or so pagan tribes in Borneo the Ibans or Sea Dyaks are the most expert, as they spend a great deal of their lives hacking down forest for fresh farming land. While the clearing is in progress the survey mandor in charge is putting in the mark and building the beacon. A few -beacons were made of angle iron and many of beliam (ironwood) like Australian jarrah, sawn, cut and fitted before being carried to the site. In the most inaccessible spots hardwood timber cleared on the site was used. Ground marks were iron pipes •2 or 4 inches in diameter, filled with concrete and surrounded 'by a block of concrete 1 ft. square and 2ft. deep, the top of the mark flush with the ground. Witness marks were 1-inch iron pipes projecting from a small concrete block.

The Wild Geodetic Theodolite was used and the observing methods successfully coped with the trouble caused by the parallel -steel centres. Observations were usually to opaque beacons ■ during the first two and last one-and-a-half hours of daylight. Some primary observations were to lamps at night and to helios during the latter part of the observing serson, which is from October to June. The landas, or wet monsoon, is from the end of October to March, with the worst period of six weeks’ rain near Christmas, The monsoon is well marked in the south-west of the country, but not so in the north-east. During the landas visibility is excellent when the weather is clear, but there is trouble with high peaks in most lying about 4000 ft. The best points are from 2000 to 3000 ft. After May, trouble with heat haze requires use of helios and the season closes completely for July, August and September. There is no high prevailing wind, but fair breezes and some coastal storms with many severe thunderstorms. Blankets, kajangs and brushwood wei;e used for weather and sun screens. Latitude and longitude were observed with the 45 deg. prismatic astrolabe by officers of H.M.S. Herald at either end of the chain Cloud much interferes with astronomical work and there is no observation at other triangulation stations. Azimuth was determined near the two bases with observations on Paloris at altitudes about 2 deg. and 5 deg. re- ' spectively. Horizontal refraction was avoided, by observing from a fairly high trig, point with R.O. distanct 11 miles.

The sides of the primary triangulation averaged 30 miles, and of the secondary 11 miles. The average error of closure in the first was 1.2 seconds. The geodetic calculations were made on Everest’s figure of the Earth and the sheets projected on Cassini’s projection with two meridians in longitudes 111 deg. and 114 deg. E. with origin of co-ordinates 2 deg. 00’ and 3 deg. 30’ N. In 1934, when the triangulation

from the western base at Matang had reached about half-way, the adjoining state of Brunei decided to invest some of its new oil revenue in a survey to be undertaken by the F.M.S. Survey Department. Co-operation was arranged, the work of the chain of triangles interrupted and a new start made at the eastern end, stations being occupied by mutual agreement and a base of 4 miles measured at Marudi by a combined F.M.S. and Sarawak party. The triangulation common to the two states was then extended to the British North Borneo boundary and south westwards to join up with the’ part of the main chain already observed, the junction being made in the middle of 1938. The probable error of the field measurement at the base was 1/1.000,000. The length closure was 1/200,000; the azimuth, latitude and longitude in each case 2 seconds; and the closure in height 12 feet. The western heights were based on a mean tide-level as Kuching 20 miles from the sea, and the eastern on mean sea-level from an automatic tide gauge at Miri oilfield The simple chain of the triangulation was adjusted figure by figure with no through adjustments for latitude, longitude and length closure. I would like to say a word about training and preparation of observers for trig. work. There is an impression that proficiency in primary observing is something mysterious and that the trig, observer is by virtue of his occupation a much more skilled observer than his brothers engaged on less majestic work. In my opinion this was not true even in the days of observation with heavy and complicated instruments, and certainly is not in these times of modern light precision theodolites. An observer wants patience, capacity for taking pains, and temperament to help him face, without detriment to his work, the disappointments of weather delays and long periods of hard living and loneliness. He should have had a long training in handling a theodolite, and must respect a- delicate instrument. With these qualifications it does not matter much what kind, of theodolite he has used before, even though it be nothing more than a sin. Vernier instrument. Good eyesight for resolving minute differences of alignment in a telescope or micrometer and a light touch are the necessary physical qualifications. Having gained confidence in his new magical precision instrument such a man should be able to produce good trig, results whatever his previous, experience of trig.-survey. will generally be found that the man who. does good theodolite work on ordinary jobs can also do good triangulation. Topographical Surveys

Purely topographical surveys were mostly traverses of risers whose banks are not fixed incidentally by the cadastral work. There was triangulation of wide estuaries; then traverses by subtense from side to .side of the river; then by compass and rangefinder as the river narrows and the reaches are shorter; and for the headwaters compass and rotan traverses, the rotan tape floating on the water. These last traverses are carried right to- the sources of streams, the surveyors walking in the water. Connections of trigs, when possible are made by the usual compass and chaintraverse.

Panoramic sketches are made from trig, stations, writing the bearing and vertical angle against each peak and saddle, as observed with 3in. Vernier theodolite’ and plotting on two miles to the inch. Form lines at approximately 500 ft. interval are sketched on

Die field plot. In 1926 an air survey of the deltas of the Rajang and Sarawak rivers was made by the Air Survey Company, who supplied photographs, a mosaic . nd a map -compiled on ground control by the Sarawak Department. No stereo plotting was done. Mapping of the interlaced waterways was greatly improved. Cadastral Surveys

Minoi* triangulation, the highest class of work done by the Asiatic surveyors, was used only for isolated fixes, all-triangles being fully observed except intersected points for lighthouses. In Sarawak rhe place of minor triangulation is taken by standard traverses owing to the difficulties of clearing. The important very long traverses were by European surveyors, others by the Asiatic staff. Angles were taken by the Wild universal or the- sin. micrometed theodolate and distances by continuous steel band in catenary. The bands are six chains long, one-six-teenth of an inch wide, and weigh only about iHb., so the catenary correction is very small for unsupported lengths up to 250 feet. Temperatures were measured by swinging a thermometer on the end of a stringin control traverses with Vernier theodolite and steel bands of oneeighth of an inch wide, the angles and

linear measures were carrie4 out together. No temperatures were measured, but the bands were standardised at 85 deg. F. and all tested regularly. Town surveys were theodolite traverses similar to standard traverse work; survey of large parcels in the country by control traverse; and small lot boundaries by compass and steel band, with vertical angles by clinometers (protractor and weighted string made up locally).

Discussion

Before the paper the president (The Rt. Hon. Sir George Clerk) said: “The paper for the meeting this afternoon is by Captain D. L. Leach, Royal Engineers, who will lecture on the Sur-

vey of Sarawak. You will notice that I gently pronounced the k. I have learned from Captain Leach that that is correct in Sarawak, but that in the Malay States the k is not pronounced. “Captain Leach' is a New Zealander who passed as a cadet through the Government Survey Training, in New Zealand, and when he was qualified soon obtained a position in the Surrey of Sarawak. His subject is that survey, but in the course of the paper he will show us, incidentally, many pictures of the country. I now call upon Captain Leach. Captain Leach then read the paper printed above and a discussion followed.

The chairman (Mr W. L. Schlater): The president has had to leave. In taking his place I call upon Colonel Boulnois to say a few words.

Colonel p. K. Boulnois: At the beginning of this war we in the geographical section, of the War Office experienced difficulty in finding topographical surveyors. We were faced with the problem of expanding the survey service of the Army from 19 officers to well over’ 200, and we searched the world for energetic young men who had had topographical survey experience. I do not mind confessing that we found remarkably few available. There were a number who had done large-scale survey of small areas but few who, like Captain Leach, had surveyed large areas such as Sarawak. They were known as the Survey Irregular Cavalry, and I remember two names, Leach and Rotheray, dutposts of that Cavalry, who came back to England from Sarawak and Nigeria to help us out in the servey service of the British Army. “You have now heard from Captain Leach what the survey of a territory such as Sarawak means. From a technical point of view, the lecture was a vignette of the type of survey that these men do all over the Empire, a highly specialised type of work. Some of them work in Nigeria, some in the Gold Coast, and there were some in Malaya, but they are few and difficult to come by. Therefore I was exceedingly interested, technically, in what he had to say, and there are many, questions I am going to put to him later, but with which I will not trouble you jiow.

“Captain Leach spoke of the way in which the people in Sarawak started by not wanting' a survey by being satisfied to get their various lands mapped on a large scale quite independently, a property here and a property there;, the worst kind of survey we can have. Eventually someone finds his own particulai’ property cannot be placed on the map because there is no room for it; there has been no proper framework.

“There is one point I hope Captain Leach will deal with when he replies, whether air survey was used at all in Sarawak. We heard at our last meeting of its value in connection with, the Alaska Highway, in particular of survey by the aircraft belonging, to the (Government. That seems

to me to be the. crux of air survey. If Governments can be persuaded to use their own aircraft to produce air photographs from which surveys can be made, then the economies of the aii* survey problem will be solved. If not, air survey will not come into its own.”

Captain Leach: As to air survey, we adopted it in Sarawak for a small

portion of the territory, two of the deltas of the large rivers which made up the coastal plain. That was carried out by the Air Survey Company operating from Rangoon. It did not however, attempt any stereo-plotting. All it produced was a mosaic of photographs and an outline plan that helped us a great deal in the survey of the hundreds of channels and small waterways that make up the two big deltas. Beyond that there was nothing in the way of air survey in Sarawak, but it is to be hoped that in the future there will be a good deal more.

The chairman: I am sure we have all enjoyed an interesting afternoon and that you will agree that much gratitude is due to Captain Leach, for his account of the methods he adopted in difficult jungle country. You will join with me in according him a hear ty vote of thanks.