REPORT OF COMMISSION II: PLOTTING, THEORY AND INSTRUMENTS
9
sists of the Wild A8, Poivilliers D4, Morin
instruments, the Wild RC8 (115, 152, and 210
mm. focal lengths) and the Zeiss 30X30,
(750 mm. focal length) cameras; as well as
auxiliary equipment for numerical photo-
grammetry operations and coordinate re
corders. Both black and white and color
photography are used.
APA was organized in 1957 with eight
personnel to carry out cadastral and topo
graphic mapping at scales of 1 :500 to 1:20,000.
Equipment consists of three Photo-Carto-
graph SFOM-Nistri, Type 6.
Personnel
Photogrammetric Department of IGN :
10 geographical engineers (chief geogra
phers)
35 engineers of geographical works of the
state
65 technical assistants
300 workers (compilers, photographers, illus
trators)
A group of photographic aircraft is attached
to the Photogrammetric Department which
has important resources in personnel and ma
terial (10 teams and maintenance personnel,
12 four-engine planes, 8 twin- engine planes
(Type H.D. 34)).
Aerial Triangulation and Plotting
Instruments Employed
The Photogrammetric Department (IGN)
has the following equipment available which
is assigned to large and medium scale work;
the scale of the negatives on plates varies
from 1:3,000 to 1:30,000.
AEROTRI ANGULATION
1 Nistri T.A. 3
3 SOM Stereocomparators
3 Type B Poivilliers equipped with co
ordinate recorders
51 Type B Poivilliers—1st class equipment
with coordinatographs
2 Operators (1 compiler and 1 draftsman)
11 Poivilliers Type C (Requirements no
longer needed).
COMPILATION
The scale of the image is intermediate be
tween the viewing scale and the “restoration”
scale. For example:
[negative 1:3,000
Scale] image 1:2,000
Idrawing 1:1,000
1:13,000 1:30,000
1:10,000 1:20,000
1:5,000 1:20,000 or
1:10,000
equipment assigned to medium scale and
small scale work (1:50,000 to 1:200,000):
57 Poivilliers D (2nd order instruments).
(This type of equipment makes it possible to
make an anamorphic restitution and permits
the use of film made with the Wild RC 9
camera).
5 Stereoflex; simplified equipment assigned
to small scale work in regions with very few
hills (low relief).
A few units of Poivilliers Type B instru
ments are used for work on terrestrial photo-
grammetry (architecture, comparison of re
duced and actual models, determination of
position of clouds released by rockets, etc.).
Note also the Poivilliers Type B are out
fitted with recorders of coordinates for the
determination of points, recorded on tapes
and punch cards with a view toward the se
lections of the best highways (programming
toward computation on electronic computer
under study at the Flighway Department).
Aerial Data Recording
cameras
At IGN all the photographic coverage that
will be made use of by aerotriangulation or
by restitution are made on glass plates with
automatic Poivilliers SOM plate cameras.
The format of the plate is 19X19 cm. The
focal lengths are: 125 mm. Aquilor lens; 210
mm. Orthor lens and 300 mm. The IGN also
has cameras for SOM film (Aquilor lens, 125
mm., 19X22 cm.) used for infrared coverage;
the Wild cameras, etc.
The scale of original negatives varies from
1:3,000 to 1:65,000 for coverage made with
automatic Poivilliers SOM plate cameras.
For 1:65,000 cover (focal length 125 mm.)
the photographic height is 9,000 to 10,000
meters. Finally, the RC 9 camera enables
IGN to get cover at a scale of about 1:100,000.
RECORDING MEDIA
The infrared and color films at IGN are not
used for cartographic purposes but solely for
interpretation. It is easy and cheap to obtain
simultaneous panchromatic and infrared
coverage. The simultaneous study of the two
coverages is priceless for interpreting.
The infrared and color films are requested
by Water and Forestry Department and other
Departments.
APR profiles made in the recovery zones of
photographic strips give, after internal and
external adjustment, the required reading for
small scale restitution. In open and low