HISTORIE, TECHNIEKEN EN MAATSCHAPPELIJKE ...

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 Suriname falls in grid zone 21, with 57' West Longitude as
the central meridian, which brings a large part of the country in zone 22. In
order to project the whole area of Suriname in one zone and to apply the
scale-progression harmoniously, the central meridian was moved to
~~=55~41' W.L., with a scale factor (h0=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-airstrip) varied be-
tween 0,085 m and 0,604 m. In order to incorporate the Doppler points into
the Suriname system, the W.G.S. coordinates were converted to the Inter-
national Spheroid (datum-shift) and transformed into the modified U.T.M.
(central meridian at 55'41' W.L., scale factor h0=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 Nor-
mal Suriname Datum (N.S.P.), being mean sea level, as measured at the
mouth of the Suriname river in 1956.
This datum was spread through careful levelling and monumented by bench-
marks throughout the northern part of the country. Later during subsequent
surveying in west and south-east Suriname, this levelling-net was expanded
further, totalling about 5000 km with bench-marks at every 2 km (approxi-
mately).
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 principaly intended to serve as a basis for a new topographical map of
Suriname on the scale 1:50.000.
To incorporate the new map into the South American Continental System,
the formerly used Bessel spheriod is replaced by the International (Hayford)
spheroid, and the modified U.T.M. is going to replace the up till now ap-
plied stereographic projection.
7.6. Gravity Surveys in Suriname
The history of gravity-surveys in Suriname starts in 1945 with a single ob-
servation 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 ex-
tension in 1958 (1 15 stations).
The very promising results from these surveys gave the impetus for a re-
gional gravitational survey by Van Boekel in 1960.