= 1 
| 
De 
9t - 
(l9- 
à ve 
^ 
>iss 
Lth 
ora- 
na 
le, 
OT 
rom 
ver- @ o 
1911. 
1915 
1916 
1917 
1919 
1920 
Pfeiffer and Bauersfeld invent Zeiss parallelogram and use 
it in Orel-Zeiss Stereoautograph. 
Stereocomparator, model E, is made up. 
Pelletan makes a photographic terrestrial camera, in which 
the film is put cylindrically and the lens is rotating aro- 
und it. 
The International Society for Photogrammetry is established 
in Vienna. E.Dolezal is the first president. 
Carl Koppe died, (born in 1884), who together with lgnazio 
Porro (1801-1873) established 'Porro-Koppe principle". 
Zeiss dena tiltable Phototheodolit is made up. 
G.Pulfrich's book "Stereoskopisches Sehen und Messen" is pu- 
blished in Jena. 
September, Vienna, The First International Congress for Pho- 
togramnetry. In those early days, only Austria and Germany 
are members in the International Society for Phetogrammetry. 
About 70 officials from Austria, France, Germany,  ltaly, 
Russia and Hungary are present in the Congress. Austria,Ca- 
a, France, Germany, Great-Britain, Italy, Norway, Spania, 
Sweden and United States, participate in the exhibition. 
In his work presented within the Congress of the Internatio- 
nal Society for Photogrammetry, Vienna, Tardivo gives de- 
tails of the first aerial photographs from airplane,for car- 
osraphiec purposes. He exhibits a mosaic of the city of Ben- 
Y^ 
Stereocomparator, model E 2, is made up. 
In Germany, Max Gasser using T.Scheimpflug's ideas (1898) 
makes his double-projector employed in the vertical survey- 
i e was shown in The Geodetic Museum, in 
oyed during the Second World War. 
3 . a uos "Ty deny > 
LES. JILLS DIOUOUŸ D 
Munich, being destr 
Riedinger makes the optical cardan, an important element, 
À 
later on used in the Stereoplanigraph. 
Bagley makes the first American aerial camera, having many 
lenses, 
The first important use of an airplane on the photogramme- 
tric surveying, used in forestry (Canada). 
Umberto Nistri makes up his Photocartograph (double-projec- 
tion direct viewing stereoplotter). 
The first Autocartograph is made up, using Reinhardt Hu- 
uershoff's instructions. 
Observations on fluctuations in radio signals associated 
wich passage of alrplanes nearby determine the apparent 
beginning c£ RADAR history (Radio Detection and Range). 
9