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against any further practical application of analytical triangulation in
mapping for almost twenty years.
Otto von Gruber (1884-1942), a professor and scientific col
laborator of Carl Pulfrich became famous for his landmark publication
Single and Double Point Resection in Space” (1924). His lectures in the
Vacation Courses on Photogrammetry at Jena, first published in 1930 (with
English reprints published in 1942) provided pioneering theoretical con
cept, s (von Gruber 1942) on differential formulas of projective relations
between planes. It was von Gruber who observed in strip triangulation the
influence of errors in
his initiative, two important facts were emphasized, viz., the usefulness
of auxiliary data and instruments in order to avoid propagation of sys
tematic errors in strip triangulation and the practical advantage of
using wide-angle cameras.
Heinrich Wild (1877-1951) presented in 1926 at the Second Interna
tional Congress at Berlin his modified plotter prototype known as Police
Autograph. Subsequently he founded a factory in Switzerland (Wild
Heerbrugg Ltd.) where hundreds of well-known and w T idelv used opto-mechan-
ical autographs. comparators and (now) analytical plotters have been de
veloped and manufactured.
The Kern Co. (now in the Wild-Leitz group) of Aarau, Switzerland
joined the photogrammetric industry in 1930 and continued its contribution
up to this date. Umberto Nistri (1895-1962) of Rome, Italy and Ermeneguildo
Santoni (1896-1970) of Florence, Italy also contributed essentially in
designing and manufacturing instruments of various kinds as also in devel
oping numerous corresponding mathematical concepts. Nistri patented in
1919 a method of spatial aerotriangulation. This method, however, was
practically applied for the first time to the use of the Multiplex
equipment around 1932-33. Georges Poivilliers (1892-1967) of France,
Edgar H. Thompson (1910-1976) of the UK are credited with numerous analyti
cal contributions and with designing instruments and stereo-comparators.
Thompson's finest contributions were in analytical (matrix algebra) devel
opments, reseau techniques and aerotri-angulation by the method of
independent models. Thompson edited the British journal "The Photogram
metric Record" for 14 years. Martin Hotine (1898-1968) of the UK War
Office, although primarily a geodetist, published two landmark articles on
photogrammetry concepts, "Stereoscopic Examination of Air Photographs"
(1927) and "Calibration of Surveying Cameras" (1929).
Willem Schermerhorn (1894-1977) of The Netherlands who became a
professor at Delft in 1926, began systematic tests of aerotriangulation in
1932 and applied these ideas to uncharted lands in the East Indies. In
close cooperation with Otto von Gruber he contributed much to the under
standing of error sources and error propagations in phototriangulation. He
was also the initiator of the ISP journal "Photogrammetria". A post World
War II Prime Minister of The Netherlands, he was also the founder (in
1950) of the International Training Center (ITC) for Aerial Survey at
Delft (now located at Enschede; Schermerhorn 1964). His life was dedi
cated to the promotion of photogrammetry.
