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PHOTOGRAlJlliIETRY IN THE GEOGRAPHIC MILITARY
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by
IN~T~TUTE
OF ITALY
Francesco Maranca
A paper presented at the Fourth International Congress, Paris,
November, 1934.
Translated and Digested.
Italy's contribution to the development of photogrammetry has
been in the past, and is now, of such importance that our nation
can be considered second to none in originality of inventions and
in boldness of their application.
~arly
The Geographic Military
photogrammetric activity, in
photogrammctric map: 'that of
kilometers and on a scale of
is known in Italy anu abroad
Work
Institute, the initiator of Italian
1878 execut'ed its first terrestrial
Cava Colonnata, covering nine square
1:25,000. The name of Pio Paganini
in connection with this pioneer work.
Paganini-' s equipment for mapping in high rough. country, though
far surpassed by modern eqUipment, is worth mentioning:
Paganini Phototheodolite, Models 1875 and 1889
A graphic position plotting instrument
An instrument for graphically determining altitudes.
A survey of the present eqUipment of the Geographic Military
Institute:
A.
Ground Ph6togrammetry
2 Phototheodolites "ZeiSS" Type constructed in the laboratory
of the G. M. I.
2, Phototheodolites "ZeiSS" Type
6 Phototheodolites "Santoni" constructed in the Galileo Labs.
1 Stereocartograph "Orel"
4 Universal Stereocartographs IlSantoni" Model II.
The Geographic Military Institute resorts to photogrammetry
essentially for surveys on a scale of 1:25,000 in high mountainous
areas unsuited to plane table surveying. The triangulation control for this scale is done graphically on the plane table. For
larger sc~les, the control net is run with theodolites and positions are computed.
Since 1930, the Santoni stereocartograph Model II has made
possible plotting from photographic impressions taken at any inclination and convergency, thus greatly enlarging the possibilities of photogrammetric processes.
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For the finished scale of 1:25,000, plotting is done at this
scale or at one slightly larger and then reduced photographically.
The average daily output of each machine, at this scale, is 2
square kilometers. Up to the middle of the current year, the
G.M.I. has mapped, on various scales, over 2,000 square kilometer~J
Each year the scope of the work increases.
B.
Photoplanimetry
For some years the G.M.I. has used aerial photographs in flat
or nearly fla~ areas. The formation, in 1931, of a photoplanimetric section permitted a rationRl development of this branch
with the double purpose of making new planimetric surveys and of
bringing up to date existing surveys.
The photographs are taken in the double aereophotogrammetric
Santoni cameras; the plotting is done with a Fiechter camera
lucida.
In brin~ing old surveys up to date, the old survey is used
. for control. In original surveys, it is necessary to carry out a
graphic triangulation in the zone in such a way as to furnish
every photographic exposure with a congruous number of points well
situated for ~he control of the plotting. Elevations are spotted
and at the same time the toponamy is registered on copies of the
photographs. Although not given a large appropriation tor such
work, in 1933 and 1934 the G.M.I. has compl~ted the resurvey of
1130 square kilometers and the su~vey of 315 square kilometers.
C.
Aerial Photogrammetry.
The G.M.I. haS extensively applied the Santoni method of
aerial photogrammetry to topographic surveys, producing large and
medium scale maps at home and small scale maps in the colonies.
The first survey using this system, that of the Pisan Mountains,
was done in 1925 on a ~c8,le of 1:8,000. The altimetry is therein
expressed by contour lines.
The aerial photogrammetric section is part of the topographic
service thus making possible the most cordial and useful collaboration between the methods of the past and the present.
The equipment, the number of surveys completed, the gratifying results obtained in running the control 8nd the plans for the
future all vouch for the very rapid development of photogrammetry
in Italy.
Its actual equipment:
3 Aereophotogrammetric cameras Model II, size l3x18 em.
2 Stereoscopic pricking pins
1 Photogoniometer
1 TriangUlator
1 Stereocartograph Model I
4 Universal stereocartographs Model II
All instruments invented by Santoni.
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The G.M.I. has more particularly applied aerial photogrammetry to mapping on a scale'of 1:25,000. Continuous improvements
in method and in the selection and training of personnel has made
possible, even on this scale, an economic output superior to that
of the normal' method of ground surveying.
The reconnaissance of the ground and the toponomastic investigation, the results of which are registered on copies of the photographs, are conducted in the field contemporaneously with running
of the ground control
The plotting is done on scales between
1:5,000 and 1:20,000 and photographically reduced to a scale of
1:25,000 for the finished map. In the plotting,'one determines
the spatial point of exposure by either ~athematical resection or
by means of the Santoni apparati. (As is known, the Santoni system utilizes the taking of a photographic exposure of the solar
disc, photogoniometric readings and the position of the sun at the
instant of exposure). Perfect success in this operation requires
that spatial positions of the control be accurately determined-as is only possible when the ground work is computed.
The system has given excellent results on a scale of 1:25,000.
In thi? method, the plotting is done by means of the reconstruction
of the stereoscopic model. These results are possible because the
Santoni stereocartographs are designed for rapid and precise use.
The brilliant results of the Santoni triangUlator, recently put into use, give assurance of being able to carry aerial triangulation
through five or six successive exposures without appreciable error.
This makes one prophesy a return·to computed control limiting it
to a few photographs of each flight.
The stereocartograph operator may, without leaVing his seat,
glance qUickly from the model to the plotting sheet and may thus
leave a sheet cartographic ally complete - in no need of further
retouching.
Two operators, working alternately, ~eep each stereocartograph running continuously twelve hours a day. The' average daily
production, at whatever scale, from photographs destined for a
finished map at ~:25,000, is 6 square kilometers for the four instruments. This gives a monthly production of 150 square kilometers and an annual production of 1800 square kilometers. As a
matter of fact, the production is halved due to the very great
use of the stereocartographs for plo ting ground photographs.
The G.M.I. plans extensive aereophotogrammetric surveys in
the colonies, fOF which preparatory operations are now underway.
In this work the two lens camera will be coupled together
in such a way as to constitute a complex of four cameras. At an
altitude of 4,000 meters, a strip 20 kilometers wide may be photographed;
The Model III stereocartograph makes possible the successive
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and immediate use of all the exposures taken by the multiple
camera as soon as the position of one of ~he four is in proper
external orientation. This machine encompasses a wide range of
scales between the picture and the plotted map. The t~ci~
stylus is motivated either directly or by means of. hand wheels.
Another notable P9ssibility is the introduction of a solar.direction element in the same plotting instrument.
The year 1935 will see the- annual production capacity of the
G.M.I. increased to several thousand square kilometers.
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PREPARATION OF EXHIBITS OF THE INTERNATIONAL PHOTOGRA}~TRICAL
CONGRESS, NOVE~rnER 25 TO DECENBER 2, 1934, PARIS, FRANCE
by
Louise A. Boyd
Features: The oustanding features were displays of phototheodolites and ~he corresponding instrum nts for plotting the
photographs and maps made by them, and all kinds of cameras used
in connection With mapping.
The Great Advantage of such an International Photogrammetrical Congress is the assembling of photogrammetrical instruments
manufactured by various firms in different countries under one
roof, including exhibits of instruments, methods employed in map
making, and results accomplished by the respective instruments;
thereby enabling the making of compar~sons within a limited time.
Space Occupied in the BUilding: Space reserved for the Photo~
grammetrical Congress included raised areas along the north, westand south sides of the building and a gallery above the ma.in floor.
Set QQ: Uniform ~ackgroundswere used for all maps, photographs and instruments; and uniform colors and lighting were used
throughout all exhibits.
Space Occupied £I Exhi~: Sufficient wal.l space was alloted to exhibitors for their maps and instruments to facilitate
study and examination under the best possible conditions.
A majority of ~he instruments were concentrated on one side
of a corridor where a constructive display of maps made by the
firm's instruments were shown together with the instruments, and
additional eXhibits were located directly acrosa this corridor.
On the north side of the Grand Palais were the exhibits of the
follOWing countries: Germany, Zeiss, Jena; SWitzerland, Henri
Wild, Heerbrugg; and Italy, Nistri, Galileo, and Santoni. On the
south side were located instruments and maps by the French m8~ers
and maps exhibited by various countries. These maps, in.most
cases, had been made b~ instruments oxhibited elsewhere in the
building.