JOINT INDONESIAN AND AUSTRALIAN SURVEY
OF THE BORDER BETWEEN
THE TERRITORY OF PAPUA NEW GUINEA AND WEST IRIAN
The specifications for this joint survey were agreed upon by Australian and Indonesian survey authorities at a meeting held in Djakarta in August 1964. In essence a survey team from both countries would occupy the agreed points, independently perform the astronomical work to determine position, and then agree on the location and establish a permanent monument. Upon agreement of consecutive monument’s positions, the final stage of photogrammetrically marking, as accurately as practicable on air photographs, the geodesics connecting the monuments, would again independently be performed before final agreement of the border’s position.
From 1848 negotiations on the location of the border had taken place between successive governments, of Netherlands Indies, British New Guinea, German New Guinea, Australia, United Nations Temporary Executive Authority and Indonesia. At that time the Netherlands Indies Government laid claim to the land west of the 141st meridian.
In 1893 a joint British-Dutch expedition established that the mouth of the Bensbach River at the south coast was at longitude 141º 01' 47.9" and, as there were no natural features at that longitude it was agreed to make this meridian the border from the coast north to the Fly River. In exchange for this 1' 47.9" strip of land Britain was to take the land contained between the western loop of the Fly River and the 141st meridian.
An Australian surveyor A.G. Harrison unilaterally made astro-observations at Wutung, on the north coast, and in 1928 placed a concrete cairn inscribed:
Lat 2º 35' 28"
Long 141º 0' 13.5"
The Dutch border is 400 metres west.
He then marked the 141 degree meridian for 9km south to the Moso River, where he placed a second cairn. Both of these cairns were located, and connected to, during the 1966 survey.
A.A. Chauncy, an Australian surveyor and member of a joint Australian Dutch team, observed at the cairn at Wutung in 1933 and agreed with Harrison’s longitude to within one second of arc. In 1936 the two governments agreed that the boundary would be the 141st meridian running south from this point to the northern intersection with the Fly River, at latitude 6º 19'S.
A joint Australian-Dutch expedition again fixed, in the early 1960s, a longitude for the mouth of the Bensbach River at 141º 01' 07". They placed marks where this meridian intersected the Fly River at latitude 6º 54' south and where meridian 141 intersected the river at latitude 6º 19' south.
Air photography of a 20km wide strip along the border was flown during which time the Dutch left West New Guinea. PNG Department of Lands surveyors observed astro-fixes at all villages close to the border, to determine on which side they lay, and these fixes were used to control the photography for mapping. The mapping was subsequently completed by Division of National Mapping.
In 1963 a Department of Lands party unilaterally attempted to place notices on tracks and roads crossing the border saying ‘New Guinea International Border (approximate position only)’ but a confrontation occurred with an armed Indonesian patrol and the surveyor was arrested. The political embarrassment led to this project being abandoned.
To finally resolve the issue, in 1964, the Director of National Mapping in Australia, B.P. Lambert, the Papua New Guinea Surveyor General and Senior Surveyor John Macartney, who was eventually to lead the Australian team in the border marking operation, conferred with survey authorities in Jakarta. Proposals for marking the border were put to both governments and subsequently approved. Two years later the Indonesians attended a second meeting and the survey eventually began in June 1966.
The final, agreed, border would consist of three sections. From north to south:
ten markers placed on the 141st meridian of east longitude until it intersected with the Fly River at approximate latitude 6º 19'S;
the course of the Fly River from approximate latitude 6º 19'S, to approximate latitude 6º 54'S;
four markers placed along longitude 141º 01' 07" from the Fly River, at approximate latitude 6º 54', to the south coast at the mouth of the Bensbach River.
The sites for the markers were selected to be near or on routes used by local people, such as rivers, or on significant major natural features, such as where the line crossed the Star Mountains.
The location of the border between successive markers would be defined by geodesic lines as plotted on the existing aerial photography.
It is interesting to note the similarity of the 1964, Indonesian/Australian specifications to the Dutch/Australian specifications from the Delft, 1960 and Port Moresby, 1961 meetings.
The first nine kilometres from the north coast, marked out by Harrison in 1928, gave an introduction to the conditions which would have made lineal marking of the border on the ground physically impracticable. Through dense rain forest the meridian climbs from the coast to 1500 metres then down to 150 metres at the Moso River. Further south it traverses the limestone Border Mountains where collapsed caverns leave huge vertical sided holes tens of metres deep, and the weathered surface rocks have razor sharp ridges which can cause a stumbling walker to suffer gashed legs. In the Star Mountains the weather caused problems for the observing teams, Indonesian and Australian, who had to be left at 12,000 feet for three weeks when the helicopter could not reach them. It landed the day the emergency rations ran out. Then going towards the south coast there are long distances of thickly forested swamp
At each site selected for marking, the two teams, Indonesian and Australian, observed independently, each on their respective sides of the meridian. The two observing stations were connected by direct measurement, the results for longitude compared and, if they agreed within the prescribed limits of accuracy, were meaned. Separate traverses were then measured to the meridian, once again compared and meaned, and a site for the meridian marker established.
As markers 11 to 14 were to be on the meridian passing through the middle of the mouth of the Bensbach River, this meant that marker 14 had to be established prior to 11 – 13, to define the meridian required.
The reconnaissance, monument establishment, survey observations and calculations took place during 1966 and 1967 establishing monuments 1 to 6 the first year and the final 8 the next.
At each of the fourteen points it took approximately two weeks to complete the work required.
The coordinates for the common points as determined by each team had to be within four seconds of arc. If the results differed by more than this figure the positions had to be re-determined. The final values show the mean differences between the Indonesian and Australian coordinates over the fourteen stations to be around 25m in latitude and 40m in longitude.
On the north face of the Australian pillars was inscribed:
BAS (BAS = Border Astro Station)
(number of the site)
In the north face of the Indonesian pillars a marble slab was set and this was inscribed:
TA (TA=Titik Astro)
(number of the site)
Recovery marks were placed at suitable positions about these pillars.
During the monumenting of points 1-6 where a concrete marker was placed, consisting of a base 100 centimeters square, mounted by a frustrum / truncated pyramid 160 centimeters high and having a base 60 centimeters square and a top 40 centimeters square some 3 TONS of concrete were required.
It was foreseen that during the second year great difficulty was going to be experienced in finding suitable materials with which to make concrete, especially point 7 and points 11 - 14.
Agreement was therefore reached that at such points the meridian monuments be prefabricated from aluminium with the dimensions and shape being the same as the monuments placed up to point 6.
Each monument was set in a clearing of 50 metres radius with recovery marks emplaced and were inscribed as follows.
On the north face: Longitude
On the east face: Aust
On the west face: Indon
The geodesics (the line of shortest distance between the two points) connecting the meridian markers were located photogrammetrically and marked as accurately as practicable on the air photographs.
Each country again, undertook independent photogrammetric location and provided its results to the other. An agreement was then reached on the meridian marking and on the best approximate photogrammetic location of the Border.
Indonesian – the surveyor in charge was Dr J Soenarjo, Principal of the School of Astronomical Surveying in the Institute of Technology, Bandung. Just prior to the end of the second stage of the project he was replaced by Captain Tawil.
Australian – the surveyor in charge was John Macartney. For the first three stations David Cook of Division of National Mapping carried out the observations, until all were familiar with the first order astronomical equipment, which had not been used in PNG before. Then Bruce Willington, PNG Department of Lands, completed all the remaining stations. Two assistant surveyors, Mirek Erben and Jack Edmondstone, were responsible for locating and establishing all the sites before arrival of the observing teams
Macartney, J.C., 1968. Survey of International Border between West Irian and the Territory of Papua and New Guinea, The Australian Surveyor, Vol. 22, No. 4, pp 249-262.
Sinclair, J., 2001. Mastamak: The land surveyors of Papua New Guinea, Crawford House Publishing Pty Ltd, Hindmarsh: South Australia.
Other unreferenced sources.
(compiled by Paul Wise)
Photographs of Moument Markers 1 and 4-14 follow:
Sample photo ident showing independency of stations