door Peter van der Krogt.
Utrechtse promoties in kartografie
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It is the intention of this publication to give an insight into the mapmaking,
which underlies the disclosure of our country and the broadening of the
geographical knowledge of it.
In our opinion no material will serve better or more powerfully than the
many maps, which form the heritage of three centuries of hardy surveying.
Other resources from which we drew a great deal of our information are
the many protocols, reports and accounts concerning the map material, extant in the archives of the Office of Lands, the Central Bureau of Aerial
Surveying and the library of the Suriname Museum in Paramaribo.
In addition the standard work on the history of cartography in Suriname,
"Links with the Past" by C. Koeman et. al. was extensively consulted.
A spectacular opening up of the country by means of roads started in 1947
when the Welfare Fund programma came into being.
The so-called East-West communication-road and the forest-passage roads
were established reaching from the Corantijn-river (west-boundary) to the
Marowijne-river (east-boundary).
By means of seven airstrips built for the Grasshopper project (geological and mining research programme) also the remote interior became accessible.
1.2. The West-Indies
The oldest subdivision of the West-Indian islands dated back to the Spanish
episode and is connected with the trade winds.
A more time-bound division is the one according to nationality.
1.2.1. The Caribbean sea, initially the property of the Spanish Crown was frequented in the beginning of the 17th century by Dutch sailing ships, the so-
called "zouthalers" (fetching salt).
Also Dutch pirates penetrated this "mare clausus and started the clandestine slave-trade.
Then, in 1621, the chartered West-India Company (W.I.C.) was established
having war-fare, buccaneening and commerce as its purpose. From this later on patronages originated, which caused the W.I.C. to become also a supplier of slaves.
1.2.2. The West-Indian Atlas of Thomas Jefferys dates back to 1775 and contains
forty maps and charts (altogether) based on measurements while the compiler considered his Atlas as the first English "Pilot for the West-Indies".
The maps are preceded by an extensive "Introduction , in which attention is
given to the applied prime meridian for the map-projection, the astronomical observations, data and colonization, products, number of plantations etc. From this atlas a number of maps are discussed.
Another 5 maps compiled during the first half of the 19th century extant in
Map and Plans in the Public Record Office (by P.A. Penfold) call for attention.
Important collective works of British Cartography are among other the
Blathwayt-atlas and the map of Popple (1733).
From this Blathwayt-atlas the map of the island of Monserrat (1673) is discussed, according to J.D. Black's commentary on the Atlas.
1.3. Netherlands - Antilles
1.3.1. There were maps of these islands at a very early data, most of them however only in outline.
First, six synoptical maps of the Netherland Antilles will be brought in the
spotlight, after which some specific maps of the islands will be separately
discussed.
1.4. Berbice, Essequibo and Demerary
1.4.1. The map collection for the Venezuela-British Gyana Boundary Arbitration
(1897) contains many maps of Guyana including eleven historical maps,
illustrating the European possessions between 1597 and 1803 (1814).
Between the regional maps of this area there is a manuscript map of A.
Maas (1706), a map of Storm van 's-Gravesande (1748) and one of J.C. Heneman (1773-1775).
Furthermore there are many maps dating from the 18th, 19th and 20th century, from which some are discussed.
1.5. French-Guiana (Cayenne)
1.5.1. Charts and maps.
Plantation maps as known of Suniname and (British Guiana) now Guyana,
are not existant in French Guyana; their charts however are similar to those of our country.
Several charts from the 17th, 18th and 19th century are mentioned while
some 14 maps, among which, that of du Val d'Abbeville (1654), BuacheMentelle and Poirson between 1802 and 1821 along with that of Van Panhuys (1908) are discussed.
The West-India Company had to establish stable agricultural settlements on
the conquered places, proper management of the colony and ground rules for the exploitation of the land.
In the beginning colonists were given a free piece of land, with the legal status of ownership. Warrants were isued to the planters, containing the only obligation of bringing the land under the plough and to register with the
Secretary.
Many planters misused the freedom and seized disproportionate areas of the riverbanks and thus brought expansion possibilities into grave danger. In 1685 a maximum area of 1000 acres was put on plantations, as well as a ruling on the breadth of the river-frontage and depth of the parcel. The recipient now had to pay a yearly rent and was required to have his parcel surveyed.
To get an insight into the land-issue, cadastral maps were compiled (F. de Wit, J. Sas en A. de Lavaux).
As appears from the diverse proclamations and "reminders" the requirements of surveying and registering the land were not always complied with.
The obligation of surveying was also laid on lots in Paramaribo (year of foundation 1683) (city plans: De Wit, Ottens and G. Palm).
2.2. Some fundamental maps of the 17th and 18th century
As early as 1667 the surveyor Willem Mogge was sent to Suriname to make
a "pertinent and accurate map of the whole of Suriname".
What was meant as the whole of Suriname is described in the title of the
map. This map appeared in 1671, showing the names of the owners of the
sugarplantations in Roman letters.
Mogge's map was followed in 1686 by that of the "Labadisten", from which
one could surmise that the number of plantations has risen to 148 (Mogge
showed 100). Further it shows that the entire Para-river and the left-bank
of the Suriname-river have been abandoned, most probably due to the raids
of Amer-Indians in cooperation with the Maroons. One cannot set a high value on these maps as surveying documents as contrasted with the cadastral map of F. de Wit issued in 1688.
2.3. De Lavaux and his work
With his biography Alexander de Lavaux is introduced and his map of 1737
extensively discussed.
Still four editions of this map were issued, the latest around 1770 by P.
Schenk en Zoon, the merits of which are entered into.
2.4. The work of J.C. Heneman
In the inventory of P.A. Leupe (1867) note is taken of a number (40-odd manuscripts) of maps of J.C. Heneman.
We dwell for some time on his 1784 map and the manuscripts of his undated 140-sheets map (enlargements).
Based upon a closer inspection of some of these sheets and comparing them
with wellknown historical and other facts, we came to the conclusion that
this 140-sheets map was completed after 1794. Furhter, that it took Heneman some 10 years to finish his enlargements and not as Sypesteyn assumed
that Heneman completed his 1784 map in that short time.
Although, on one hand, the plantations along the upper courses of the rivers
were abandoned, on the other, the plantation-economy became concentrated along the lower reaches of these rivers and in the so called "New Colony". The last was settled primarily by English and Scots of which the toponyms in Nickerie and Coronie are silent witnesses (British interregnum
1799-1818).
The decline in agriculture was due to war in Europe, the loss of the sugar-
market because of the Continental System, while our cotton could not
compete against that of the USA.
The plantation economy received its death blow with the emancipation of
slaves; surveying in Suriname also hitting a low-point at that time. In order
to put the economy back on its feet small farming was taken up and attention was paid to the gold exploitation.
The activities of the landsurveyor W.L. Loth have contributed greatly to
this exploitation.
3.2. The maps of Loth
Loth surveyed and mapped among others three traverses along which the
Governement issued gold-concessions (grants).
The first traverse connected Brokopondo on the Suriname river with Pedrosungu on the Marowijne river.
The second started on the same spot on the Suriname river and ran in a
western direction to the Saramacca river; while the third reached from upper-Tempati river to Boschland, also near Brokopondo.
A synopsis of the situation regarding the granting of gold exploitation is
given in a map of Loth from 1879 (scale 1:40.000).
He surveyed also two traverses in the Saramacca district. His work has
been set down in reports in several volumes of the (T.A.G.) Journal of the
Dutch Geographical Society, along with the activities arount the gold mining.
Finally Loth surveyed another traverse in 1892 running between the Tapanahoni river and the Sara creek, after the area between the Tapanahoniand the Lawa-rivers was unconditionally declared Suriname territory by the
arbitral judgement of Czar Alexander III of Russia.
Another synopsis of the 163 plantations still in cultivation and the land-
grants on gold and other minerals is given in the map of J. Kuyper (scale
1:800.000) and published after 1882.
As coping-stone on the activities of Loth we mention his synoptical maps
from 1889 and 1899 (both on the scale 1:1.000.000).
In his second map (1899) Loth corrected some mistakes he made concerning
the boundary with (British) Guyana and indicated the New River (upper-Corantijn) as the border.
3.3. Cateau van Rosevelt and his map
First of all a concise summary is given of the geodetic qualities of the
selfmade man Cateau van Rosevelt, where-after his map from 1882 is extensively discussed. It took him and the luitenant J.F.A. van Lansberge 19
years to complete this map.
The original manuscript map, consisting of 31 sheets on the scale
1:100.000, was issued later on on the scale 1:200.000 (10 sheets).
The printed series lack the itinerary of the surveying trips, the geographical coordinates derived from astronomical observations and the several
crops distinguished by color, all of which we find on the manuscript series.
The expansions of Paramaribo from 1784 till 1882 are also discussed along
with the atlas of A.J. Meyer (1885) containing the "Figuratieve platte grond
der stad Paramaribo". (Figurative plan of the city of Paramaribo).
3.4. Astronomical observations
The very poor data concerning the astronomical observations in Suriname
Id not start in 1744 with the determination of latitude by Charles de la Condamine on the square in front of the Court of Justice in Paramaribo.
Appearing in sequence of time are some hydrographical charts in which
latitudinal and longitudinal determinations are indicated and the "Stenentrap" (compass-rose on the stone wharf) is introduced.
The number of astronomical observations increased as Cateau van Rosevelt
got on with his measurements and Lieutenant van Stockum (1911) performed observations downstreams of the main rivers on behalf of the topographical mapping of northern Suriname.
Lack of adequate time-determinations results in poor longitudinal fixes;
both mr. P.W. Sachs (former staff-officer on board the naval vessel Z.M.
Suriname) and Prof. dr. J.J. Müller criticize the methods employed. Finally
in 1947 new observations were conducted employing the method of simultaneous determinations of latitude and longitude.
3.5. A review of magnetic declination in Suriname
Comparing maps before 1801 with maps of later date it appears that the
plantation-boundaries (dikes, dams) were not oriented according to the true
north. For the first time surveyors were ordered that "the four cardinal dihas rections must be shown on the maps according to the true bearing in an inf the struction dated December 17th, 1782. W.L. Loth statet that the surveyors
interpretation of the term "true bearing" was the direction according to the
compass because the north-oriented boundaries varied from the present-day
(1905) indications of the compass-needle by 5o-7o. Using some publications,
maps and reports a summary is given of the course of the magnetic declinay the tion for Paramaribo since 1500 recording the greatest eastward deviation
(7½o) around 1650, while in the middle of the 19th century the zero-isogoand- nic line ran over Paramaribo.
Shortly after the initiation of the gold-industry in 1875 a new instruction
for surveyors was drawn up (september 21st, 1877 no. 9) in which it was ordered (art. 11) that the true and magnetic north should both be indicated on
the maps of measured parcels.
This however was not complied with. A juridical decision of the Court of
Justice (November 15th, 1902) solved this problem
Surveyors applied to the Governor in requests concerning this matter. This
resulted in putting into use the "Manual for determining the corrections of
a boussole and setting the time". Since that time surveying has been conducted according to the true north.
A few years later (1905) a Surveyor's Association was founded and a course
designed to make the surveyors more competent in their profession.
3.6. Surveyor's Instructions
From the moment that Willem Mogge, the first Dutch surveyor accepted
his assignment, he received surveying-instructions.
His successors were als bound by certain directions such as those of August
1st, 1724; of December 17th, 1782 and September 21st, 1877. Another instruction was issued on April 27th, 1915 giving directions concerning measurements and staking out plots granted in concession for certain purposes.
The next instruction dating from July 6th, 1927 pertained to the prosecution of the profession of landsurveyor in Suriname.
Art. 8 of this instruction prescribes a separate ruling of the ways how the
surveyor has to perform his function.
The safety of navigation demands reliable charts more so in connection
with the phenomenon of the movement of mudflats along the Surinamese
coast.
A series of new charts are issued by the House of van Keulen in 1785, showing great similarity to the Heneman map from 1784. Not very surprising,
considering the fact that the Heneman map is also issued by Van Keulen.
What, however, strikes us as accidental is the toponym "Abrina , a village
on the Marowijne river, long before Kappler, who is said to be the founder
of "Albina", came to Suriname.
The chart of E. Thomson and others from 1783 still indicates the
Saramacca estuarium as shown inaccurately on the map of Lavaux from
1737.
An important contribution to the hydrographic charting of Suriname was
made by the Dutch Navy. As an example the chart of naval-lieutenant J.
Vos from 1845 is discussed; with this chart a tradition starts for years on
end (40 years). Another chart, that of F.A.A. Gregory appeared before the
footlights (1860), followed by an explanation of the chart issued in 1887 by
the Marine Department. The scale of these charts was 1:750.000 which became traditional on charts of the Surinamese coast.
Apart from these synoptical charts of the coast, also charts of the separate
rivers and river-entrances were compiled mostly on the scale 1:75.000 using
the Mercator projection and giving heights and depths with mean sealevel
as a reference (2-3- foot above low-water spring).
The most recent hydrographic surveys took place between 1967 and 1973,
while the latest charts were issued in 1976.
4.2. The poly-thematic map of Zimmermann 1877
Zimmermann, using the manuscript map of Vermeulen, issued this map on
which all economical, geological, pedological and historical informations of
the Suriname-river basin is given in a surveyable fashion. The mentioning of
the local (Sranan) toponyms, along with the official geographical names is
very unique.
Consulting the map it appeared that the plantation-area along the Suriname
river dwindled down to only 2329 ha (33 plantations) where 2835 local laborers and 1396 immigrants were employed. Attention was also given to hydrography and the gold-industry.
4.3. Other thematic maps
4.3.1. In many instances these were produced to illustrate reports and through
that to awaken interest in our country.
From 1899 for instance there is the map of Loth giving an overview of agricultural land-area, gold-exploitation and the balata-industry along with
the projected steam-tramline through those areas. An other example is
Kietzmann's map (1905), the first map that we know with certainty to have
been printed and published in Suriname. Kietzmann is chiefly concerned
with the shrinking agriculture areas, the actual gold concessions and the rise of the balata industry. Also noticeable on this map are the indications of
the Savannah belt in Suriname.
4.3.2. The map for the World Exhibition 1910.
A Dutch Commission was established to gather data to be used in the world
Exhibition at Brussels in 1910.
Although data were available concerning the economy, such as agriculture,
balata-exploitation, demography etc. these were not featured on the map.
Much space however was dedicated to the spreading of schools and churches of the Moravians and Roman Catholics.
4.3.3. The "balata" map of 1912.
This paragraph gives us the opportunity of going into another aspect of the
Surinamese economy, quoting one and another from the book by Struycken
de Roysancour and Gonggrijp: The balata problem in Suriname (het balata
vraagstuk in Suriname).
The authors criticize the extant legislation on the balata-industry especially concerning the surveying and cartographic aspects. The map itself executed in colours and as far as the content goes is identical to the Exhibition-map of 1910 supplemented with indications concerning the situation of
concession-grants (exploration and exploitation).
A separate map on the scale 1:1 million was issued in connection with the
ordinance of 1914 (G.B. 1914 no. 51). This map, entitled "Map belonging to
G.B. 1914 no. 51", is a reduction of the map of Spinet (1913) and contains a
division in 63 blocks, each with a Roman number and the acreage.
4.3.4. The synoptic geognostical map of K. Martin (1888).
Prof. K. Martin made a first experiment of some geological formations of
Suniname in two synoptical maps.
As a base he used the map of Cateau van Rosevelt (1882). He encountered
some difficulties in indicating correctly the boundaries between distinct
geological formations because of inadequate mapping especially in the
Corantijn river.
As a predecessor to the real expeditions mention is made of the mapping of
the upper reaches of the Nickerie river by C. van Drimmelen (see: T.A.G.
XVI, 1899).
The intention of the scientific expeditions, was above all the procurement
of more geographical data on the interior of Suniname. Interest was taken
in the mountain-systems, especially because of the possibility of using their
tops for the mountain triangulation.
The first expedition, the Coppename expedition, laid the foundation for the
first circumferential measurements. These were taken from the Voltz- and
the Van Stockum mountains while the oronyms Wilhelmina mountain, Emma
ranges and Hendriktop, originated from L.A. Bakhuis (leader of the expedition)
The second expedition went up the Saramacca river, with the assignment to
climb the Jan Basigadotop and take bearings therefrom. Thereafter the
mountain panorama's were to be seen from the Hendniktop and finally to
climb a third mountain in the source-region of the Saramacca river, which
should yield further data of the Wilhelmina range.
Van Stockum, the leader of this expedition could already conclude from the
observations made, that the Wilhelmina range and the Tumuc-Humac mountains ware separate mountain ranges.
Although not yet known by that name and hardly discernible because of the
clouds, the "Tafelberg was detected.
Apart from topographic data also geological, botanical and zoological material were gathered.
The Gonini-expedition, the third in sequence, chose this region for her investigation in connection with the construction of a railroad from Panamanibo to the Lawa river. New ononyms were added to the list, such as Manlobi, the Goeje mountains, Knopaiamoi and the Lely mountains.
Also hydronyms were added such as the Emma- and the Wilhelmina rivers
as tributaries of the Gonini river. On the Kniopaiamoi, near the Litani river
large magnetic anomalies were recorded. In addition to large quantities of botanical material and stonesamples a hundred-odd Indian tools, as well as
impressions, of bush-negro wood-carving designs were gathered.
The fourth expedition, known as the Tapanahony-expedition, was commissioned to make connecting links between the mountain tniangulations of the
Saramacca- and Gonini-expeditions and further to reach and reconnoitre the source area of the Suniname river through a journey overland.
The Palumeu and upper Tapanahony were mapped, whereby significant
anomalies were registered near the Magneet rots (magnetic-rock) and near the Kasikasima.
To make the connecting link between the mountain tniangulations four
peaks were scaled: Tebu, Magneet rots, a peak of the Kasikasima and a
peak near the Papadronsula (rappid in the Palumeu river).
The positioning of Tebu, derived from the western system compared with
the position of the same top triangulated in the eastern system gives a discrepancy of 31" in latitude and 1'20"e; in longitude.
After the Tapanahony came the Tumuc-Humac expedition which was
assigned to reach the source area of the Palumeu and from there on reconnoitre the area between these sources and the head waters of the
Corantijn. Further in connection with the boundary determination between
Suniname and Brasil as much information as possible relating to the
watershed was to be gathered.
The results of this expedition did not lead to any spectacular map work.
As usual some attention was given to investigations concerning geology and
anthropology; also an expanded word-list to trading terms between the
Ndyuka's and Trios, as well as a list of Ndyuka words, which differ from
common Sranan, were composed.
The Suriname-expedition - the sixth in the set - had to reconnoitre the upper Suniname river region, connect the mountain-tniangulations of the Tapanahony and Gonini-expeditions with those of the Saramacca and Coppename expeditions, to travel - if possible - oven the watershed between the headwaters of the Suniname river and of the Corantijn, and reconnoitre the
latter. (This last mentioned task was not realized).
The 7th and last of these expeditions, the Corantijn-expedition had to investigate the Corantijn region, especially the stretch of land lying east of it.
The compilations of the findings of all these scientific expeditions in one
map, published originally in 1913 and re-issued in 1927 was done by Spinet,
chief of the Surinamese Suryeying Brigade. This map can be seen as the first to render the complete framework of headwater-courses and the most
outstanding mountain ranges in their proper relationship to each other and
oriented on the true north.
A practical benefit of this map was its use as a basis for a synoptical map
for the division into blocks of the balata-exploitation areas.
In the year 1911 Spinet was installed as Government-Surveyor and given
the task of bringing about improvements in the cadastral and topographical
situation in Suniname.
To obtain "fixed-points" to which the surveys could be related,
astronomical observations were carried out at various places in the coastal
area.
These points were tied together with base-lines (traverses) hooking up with
property-surveys, thus serving cadastral purposes and topographical m easurements. Between 1912 and 1919 a total of 2534.2 km of baselines were
measured; thereafter Paramanibo was surveyed.
By 1919 a total of 66,522 ha was surveyed and mapped on the scale 1:10.000
and reductions made on the scales 1:50.000 and 1:200.000. However only 17
sheets (from the 320 planned were printed (including one of Paramaribo).
As a datum for the vertical measurements in these surveys the lowest
known water level on the tide-gauge at Beekhuizen between 1904 and 1909
was taken. The task of Spinet included the connection of the mountain-
triangulation network with the astronomical fixed points in the coastal
belt.
6.3. Geodetic base for a Cadastre of Paramaribo
At the intersections of all streets in Paramanibo, heavy concrete markers were set up, half a meter below groundlevel.
The lines connecting these points together formed a dense net which provided the base-lines for the measurement of the lots in the city.
The project, started in 1913, was stopped in 1915, leaving everything thereafter untouched. By then the net-work was finished but only a few lots had their boundaries fixed.
6.4. The map of Bakhuis and De Quant (1930)
With the help the basic data i.e. the results of the scientific expeditions, 26 astronomical stations set up by Van Stockum in 1911 and 1912, the work of the surveying Brigade and corrections in longitudinal, observations made by Kremer in 1927 using precise time-measurements, Bakhuis and De Quant in 1930 issued a synoptical map in the scale 1:200.000 in 16 sheets.
An abundance of geographical names makes this map extremely important,
the nomenclature being almost all still in use to day. This map had become
urgently needed in connection with the granting of concessions, since the
official map for the balata industry, that of Cateau van Rosevelt, appeared
inadequate.
The Bakhuis map constructed according to the Mercator projection serves
even today as the official map for requesting and granting parcels of land
for concessions of any type.
The US Airforce conducted an aerial survey in Suniname in 1943 for the purpose of making aeronautical maps. (World Aeronautical Chart). The survey was done according to the tnimetrogon system while a comparison of the thus produced maps with the one to a million map of Suniname from the Central Bureau for Aerial Survey (C.B.L.) clearly points out the short-comings of the beginning phase of photogrammetny.
An aerial survey of northern Suniname of higher quality was performed in
1949 by the Cartographic Service of KLM.
A total of 10,419 photos was taken in the scale 1:40.000.
As a necessary offshoot of this commission for the systematic photographic
recording, the C.B.L. came into existence (February 7th, 1948). The frame
work of surveying was formed by 26 astronomically fixed points according
to the Gauss-method; while for orientation on behalf of the aerotraingulation traverses were measured.To obtain the elevation of the ground-control-points (astropoints) barometric observations were conducted at the site
and along the rivers, using the vertical datum of the Office of Lands-being
1,50 m below mean sea level.
The maps composed from the aerial photos were executed in the system of
the stenographic projection; having as central point the intersection of the
meridian of 55o41' West Longitude and the parallel of 40o71' North Latitude.
All geographic coordinates were calculated on the Bessel spheroid. An additional commission for mapping the southern part of Suniname (below 40o of
latitude) followed in 1956.
7.2. Airborn methods on behalf of the geodetic frame work
To set up a triangulation network of primary order, consisting of 52 points
equally spread throughout the country, the aerodist system was applied.
For orientation purpose this net was tied to some Hiranpoints. During the
first and second phase of the densification of this net the helidist method
was used and ground controlpoints were measured.
In areas where use of a theodolite was impossible, a modified helidist
method, known as "multidist was applied. Still other problems presented
themselves related to the fixing of ground-control points, whereby neither
helidist nor multidist could be used. In those cases terrestrial methods such
as traversing and/or tnilateration were applied.
Height-data were established partly by first order leveling and partly by
barometric measurements.
The adjustment of the aerodist net only, dit not provide a satisfactory result in all respects; an integral adjustment however of aerodist and helidist
measurements together yielded acceptable values.
The geographic coordinates finally obtained by adjustment and scaling on
the Hiran-net were converted into the U.T.M. system based on the
International spheroid.
In this system Suniname falls in grid zone 21, with 57o West Longitude as
the central meridian, which brings a large part o( the country inzone 22. In
order to project the whole area of Suniname in one zone and to apply the
scale-progression harmoniously, the central meridian was moved to
Xo=55o41' W.L., with a scale factor (ho=0,99990).
7.3. Doppler Satellite Positioning
As third phase in the densification on behalf of the aerial mapping the south-east corner of Suriname could finally be surveyed in 1977, using the Doppler translocation system. According to the required accuracy of the coordinate-values, the short arc geodetic adjustment was also chosen. The standard-deviations of the coordinates in the World Geodetic System 1972 (W.G.S. 72) related to the base-station (i.c. Palumeu-airstnip) varied between 0,085 m and 0,604 m. In order to incorporate the Doppler points into the Suniname system, the W.G.S. coordinates were converted to the International Spheroid (datum-shift) and transformed into the modified U.T.M. (central meridian at 55o41' W.L., scale factor ho=0.99990).
7.4. Primary levelling
The need for establishing a uniform vertical datum became urgent when in
the early fifties of this century the Brokopondo Project and other activities
which would influence hydrology down streams, were being planned.
In September 1957 a uniform datum was introduced referred to as the Normal Suniname Datum (N.S.P.), being mean sea level, as measured at the
mouth of the Suniname river in 1956.
This datum was spread through careful levelling and monumented by benchmarks throughout the northern part of the country. Later during subsequent
surveying in west and south-east Suniname, this levelling-net was expanded
further, totalling about 5000 km with bench-marks at every 2 km (approximately).
7.5. The new topographical map 1:50.000 (Central Bureau Aerial Surveying)
The geodetic frame work and levelling discussed earlier in this chapter
were pnincipaly intended to serve as a basis for a new topographical map of
Suniname on the scale 1:50.000.
To incorporate the new map into the South American Continental System,
the formerly used Bessel spheniod is replaced by the International (Hayford)
spheroid, and the modified U.T.M. is going to replace the up till now applied stereographic projection.
7.6. Gravity Surveys in Suniname
The history of gravity-surveys in Suniname starts in 1945 with a single observation by Harding at Zanderij-airport.
A more extensive survey in connection with the International Geophysical
year (1957-58) was conducted by Veldkamp (19 stations) followed by an extension in 1958 (115 stations).
The very promising results from these surveys gave the impetus for a regional gravitational survey by Van Boekel in 1960.
The area investigated on that occasion comprised the whole northern part
of the country.
The survey resulted in a gravitational-anomaly map of northern Suriname
with intervals of 5 mgal.
An extension of this map in a northerly direction i.e. on Suriname' s continental shelf took place in 1966 and 1969 by naval vessels; the iso-anomaly
chart resulting from this survey was linked to Van Boekel's observations.
Small local expansions of this gravitational network were conducted in the
region of the projected Kabalebo storage-basin and in south east Suriname;
the last was done in connection with the Doppler measurements.
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