PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING
March 2019
165
(
l
o
)= 14° E, FN= 10,000 km, FE = 500 km, and the scale fac-
tor (m
o
) = 0.9999; and Fuseau 16 where latitude of origin (
j
o
)
= Equator, Central Meridian (
l
o
) = 16° E, FN = 10,000 km,
FE = 500 km, and the scale factor (m
o
) = 0.9999. The Gabon
Belt (Fuseau Gabon) is found in use along the northern coast
(
PE&RS
, September 1998). Of course, the UTM grid is com-
mon in Angola.
The Camacupa Datum of 1948 is based on the origin at
Campo de Aviação where
F
o
= 12° 01´ 19.070˝ South,
L
o
= 17°
27´ 19.800˝ East of Greenwich, and h
o
= 1508.3 m. Thanks
to John W. Hager, “This is the principal vertex marked by
a concrete monument, constructed on a high part of the
Camacupa Air Field, immediately to the north of the run-
ways.” (
This is
) “defined as the “Datum Point” of the main
triangulation network of Angola. A concrete monument with
the dimensions 70
×
60
×
100 cm (length E-W
×
width N-S
×
height), topped by a white marble slab on which is cut in
black: M.G.A. –P.F.- 1948; in the center of which is placed
the top mark of the base, which is defined as the extreme
West of the Geodetic Base of Camacupa. The mark found
here is protected by a masonry casing with a metallic cov-
er, easily removed to permit observations over the base when
necessary.” Remarkably, some Datums established by the
Portuguese in Angola (and Moçambique) were referenced to
the Clarke 1866 ellipsoid (the same as used in the U.S. for
the North American Datum of 1927) where
a
= 6,378,206.4
m and and
b
= 6,356,583.8 m. The only transformation pa-
rameters I have ever been able to scrounge from this Datum
to WGS84 were obtained from Prof. Charles L. Merry at the
University of Cape Town where
D
X = –49 m,
D
Y= – 301 m,
and
D
Z = –181 m; and Prof. Merry estimates the accuracy at
±60 meters. According to Hager, “sometime in the 1960s or
1970s, DMA was asked to put Angola, then on the Camacupa
Clarke 1866 Datum, on the Camacupa Clarke 1880 and the
Arc 50 Datums. The Portuguese provided all the coordinates
based on the Clarke 1866 Datum. They also provided tables
to convert from the Clarke 1866 Datum to the Clarke 1880
Datum assuming that the tangent point of the two ellipsoids
was at Camacupa. I think that the tie was on the 12
th
Parallel
South to the Zambian Triangulation. (
It was
). The 6
th
Paral-
lel south and Bas Congo surveys of Congo occupy common
points with the Angola surveys and were adjusted to the Arc
Datum of 1950. A comparison of the Angola values showed
that Arc 50 Datum in Angola was adequate for mapping pur-
poses. Angola is on the UTM Grid. I did find a local grid for
Luanda and would expect other similar ones. For Luanda,
the 1:2,000-scale city map plots directly on top of the UTM
Grid of the 1:100,000-scale map. The 50,000 50,000 intersec-
tion is, in UTM coordinates, N = 9,024,000 and E = 306,000.
This then results in a local Grid, Transverse Mercator pro-
jection, Clarke 1880 ellipsoid,
j
o
= 0°,
l
o
= 15° E, FN = 1,026
km, FE = 244 km, and (m
o
) = 0.9996. The UTM scale factor at
local 50,000 50,000 is 1.00006581. A unity scale factor would
be expected for a City Grid, and this is pretty close to uni-
ty. The math for the false coordinates is FN = 10,000,000 –
9,012,000 + 50,000 = 1,026,000 and FE = 500,000 – 306,000
+ 50,000 = 244,000.˝ The Camacupa Clarke 1880 Datum is
oftentimes referred to by the hydrographic community as the
Camacupa-Vumbatumba Datum of 1950 based on the origin
surveyed by MHCA in 1950 as
F
o
= 06° 26´ 17.111˝ South
and
L
o
= 12° 27´ 22.978˝ East of Greenwich. Transformation
parameters used by Western Geophysical from the Camacu-
pa-Vumbatumba Datum of 1950 to the WGS 84 Datum are
D
X = –39.44 m,
D
Y = –353.66 m, and
D
Z = –224.16 m, and the
transformation parameters used by the British Navy are
D
X
= –48.81 m,
D
Y = –343.58 m,
D
Z = –228.32 m, ±10 meters for
the northern part of the country.
Thanks to parameters published into the public domain by
the European Petroleum Studies Group (EPSG) headed up by
Mr. Roger Lott of British Petroleum, there are a number of
transformations from the Clarke 1880 version of the Camacu-
pa Datum of 1948. For instance, Camacupa 1948 to WGS
72BE:
D
X = –37.2 m,
D
Y = –370.6 m, and
D
Z = –228.5 m; this
was derived by Geophysical Services, Inc. in 1979. Camacupa
1948 to WGS84, used by Conoco for Offshore Block 5:
D
X =
–42.01 m,
D
Y = –332.21 m, and
D
Z= –229.75 m. Camacupa
1948 to WGS84 and used by Topnav at PAL F2, by Elf in
blocks 3 and 17 since 1994, and by Total in block 2 since 1994:
D
X = –50.9 m,
D
Y = –347.6 m, and
D
Z = –231 m. An additional
eight versions of parameters are used for the “same” transfor-
mation in offshore areas spanning the entire coast of Angola.
The MHAST Datum of 1951 (Missão Hidrográfica de Ango-
la e São Tomé) fundamental point is a concrete block, point
Y, at Malongo lighthouse that is at
F
o
= 05° 23´ 30.81˝ South,
L
o
= 12° 12´ 01.59˝ East of Greenwich, and is referenced to
the International ellipsoid of 1924 where
a
= 6,378,388 m and
1
/
f
= 297. From MHAST to WGS84:
D
X = –252.95 m,
D
Y =
–4.11 m, and
D
Z = –96.38 m. The Malongo Datum of 1987
replaced the MHAST Datum of 1951, and is also referenced to
the same fundamental point (new coordinates unknown). The
same ellipsoid is used; however, the transformation parame-
ters have changed to become Malongo 1987 Datum to WGS
84:
D
X= –254.10 m,
D
Y= –5.36 m, and
D
Z= –100.29 m, thanks
to Mal Jones of Perth, Australia.
Hager went on to say; “A survey was done across Congo
(Kinshasa) connecting Angola proper to Cabinda but the data
were destroyed by a fire in Lisbon so Cabinda is on a local
datum. About all the booklet for Cabinda will say is that it is
not on Camacupa 1948 Datum. The values of the boundary
marks in the northwest of Cabinda are in agreement with
those published by (the French) IGN and used by Congo
(Brassaville).”
Other datums existing in Angola include the Lobito Datum
of 1937 based on the origin point at the astronomical pillar
Restinga do Lobito, Extremo NE da Base do Lobito, where
F
o
= 12° 19´ 00.86˝ South,
L
o
= 13° 34´ 45.67˝ East of Greenwich,
Clarke 1866 ellipsoid. Dr. José Carvalho of Maputo, Moçam-
bique states that the Camacupa Datum of 1948 coordinates
of the same point are
F
o
= 12° 19´ 01.357˝ South,
L
o
= 13°
34´ 58.375˝ East of Greenwich. The transformation from the
