672
September 2016
PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING
of Egypt, cartographer, and master of oceanography. By
today’s standards, the mapping of Turkey and the world by
the Ottoman Turks was of a thematic nature through most
of the 19
th
century. Large-scale mapping was accomplished
by planetable and alidade, with control being established
graphically through resection with the planetable. Much
of Europe had been mapped in similar fashion in the 18
th
century; with geodetic control being utilized mostly in the
latter half of the 19
th
century.
The General Staff of the armed forces established the first
Turkish surveying school in 1818. After the foundation of
both
Mühendishanei Berri-I Hümayun
(the Artillery School)
and the Military Academy, the young officers were sent to
France, England and Prussia for education on western
science and techniques. The first Cartographic Branch of the
Armed Forces was formed in 1853. However, little geodetic
surveying and mapping was performed for decades. Classical
triangulation started in the Vardar Basin, and one year
later, in May of 1896, a 7,235.520 m baseline was measured
in Eskisehir with Brunner invar apparatus. One of the
geodesists working on this project was CaptainMehmet Sevki,
later to be promoted through the ranks to Major General
and revered as the father of Turkish geodesy. Hydrographic
surveys were beginning to be performed by the navy during
these same years, and supporting triangulation was used for
numerous harbor surveys and passages. In 1909, the survey
office was upgraded to the Survey Commission. A series of
topographic maps was started in 1911, and was based on the
(1906-1923) Bonne projection where: the central meridian,
l
o
= 28º 58´ 50.8188˝ East of Greenwich, the latitude of origin,
j
o
= 39º 36´ 00˝ N, and the scale factor at origin, m
o
= 1.0.
Note that the longitude given above is but one of the various
values published for the position of the center of the dome
of the Aya Sofia mosque (originally built as the Cathedral
of Constantinople), but the Turks actually used Aya Sofia as
their Prime Meridian. (The relation of their Prime Meridian
to Greenwich was immaterial to the usefulness of Turkish
maps for Turkish applications.) The ellipsoid of reference
was the Clarke 1880 modified by General Sevki where:
a
=
6,378,249 m and
b
= 6,356,515 m. Note that these parameters
were published in 1333 of the Moslem calendar and were
hand-written in
Old Turkish
, the norm at the time, and the
angular unit of measurement was the centesimal Grad (360º
= 400
G
).
Geodetic baselines measured before WWI included:
Bakirkoy (Istanbul) 1909 (4396.703m), Edirne 1911 (2919.240
m), Adapazari 1911 (3483.862 m), Ezurum 1912 (6127.396 m),
and Aleppo 1915 (7477.857 m). The first order triangulation
performed during this period was mainly in support of the
Balkan War of 1912. By then, Brigadier General Şevki was
involved with triangulation and mappingthat extended
through much of European Turkey (Edirne Region) to the
Çanakkale Strait (Dardanelles). Remember that at the time
the Prime Meridian for these topo sheets was the Aya Sofia
mosque. Aerial photography was utilized by the Ottoman
Empire during WWI (1914-1918), but it is thought to have
been for reconnaissance purposes only. Note that during this
same time period (1917), the British were the first to use
aerial photography for actual military mapping of Turkish
fortifications in the Palestine during WWI (
PE&RS
, August
2000).
The General Directorate of Mapping was established by
law on 02 May 1925 in the newly formed Republic of Turkey.
New classical triangulation necessitated the observation of
baselines that included: Ankara 1925 (2050.426 m), Izmir
1928 (9536.311 m), Dardanelles 1929 (3250.321 m), Eskisehir
1931 (second observation), Maltépé (Istanbul) 1932 (4279.455
m), Balikesir 1933 (6106.972 m), and Korkuteli (Bozova)
1935 (6346.447 m). These post-WWI baselines were observed
with the new French Carpentier invar apparatus. With the
exception of the Edirne baseline that had an average error of
1/300,000, all the other baselines measured after the war had
errors better than one part per million.
The first Turkish ventures into photogrammetry were in
the 1930s, first with terrestrial applications and later with
aerial. Foreign consultants carried out earlier experiments.
In 1937, the first Zeiss C-5 Universal Stereoplanigraph
was purchased, and German technicians were assigned
to Ankara to assist in training as well as production.
With the Werhmach’s penchant for geodetic intelligence,
Turkish military topographic sheets somehow found their
way to Berlin. The new president of the republic, Ismet
Inönü, insisted on maintaining neutrality during WWII.
Nevertheless, there was great German interest in Turkey.
The holiest place in all of Turkey is the Aya Sofia mosque.
Being the national Prime Meridian, there was keen academic
interest in the relation of the great dome with respect to
Greenwich. The local datum for European Turkey was at the
Kandilli Observatory where the geodetic coordinates are:
j
o
= 41º 03´ 48.899˝ N and
l
o
= 29º 03´ 55.2˝ East of Greenwich.
This was also the origin for the new Gauss-Krüger Transverse
Mercator projection for European Turkey (used from 1932-
1946), and the relation of the great dome to Greenwich
was necessary in order to recast the Bonne Grid to the TM
Grid. The connecting survey between the Turkish first-order
triangulation net and the mosque was assigned in 1934 to
Major Niyazi, also an accomplished photogrammetrist. One
of the first things the major had to do was find the center of
the dome. “As it is known the upper sections of Aya Sofia are
covered with lead plates. The lead layers near the pillar were
removed, approximately 15 centimeters of earth underneath
was dug and a geodetic bronze rod was set with cement.
The center of this little bronze rod is the head of Aya Sofia
triangulation.” Previous determinations of the position of
Aya Sofia included: French Captain Gautier in 1816-1820
(Φ = 41º 00´ 12˝ N, Λ = 28º 59´ 01˝), Nautical Table London
in1888 (Φ = 41º 00´ 16˝ N, Λ = 28º 58´ 59˝), Connaissance de
Temps in 1912 (Φ = 41º 00´ 29.8˝ N, Λ = 28º 58´ 58˝), General
Sevki (Φ = 41º 00´ 26.56˝ N transferred from Bakirkoy),
and Brigadier General Abdurraham (Φ = 41º 00´ 31.034˝ N
