U. S. Geological Survey states that the photography used
for many of their projects range in scale from about
1:20 000 to 1:60 000. Most of this is vertical black
and white, supplemented occasionally with split verti-
cals and color film. Mr. Frank McBeth (3) of the U. S.
Hydrographic Office prepared a paper on the use of aer-
ial photography while investigating leaching and sapping
as an erosional process.
France:
Professor Jean Gandillot (1) in his paper summarizes
the technical progress in France in the use of aerial
photography.
Norway:
Mr. Arne Haider in his technical Report from Norway
to Commission VII states that: Aerial photos has in
some degree been taken for use in separate analysis by
& number of institutions. Among these institutions are
the: The Geographical Institute, University of Oslo,
the Norwegian Geological Institute of Soilbank Investi-
gation and Federal Road Administration, the University
of Oslo (by geomorphological studies). Mr. Haider also
indicated that the following publication by O. Einevell,
"Photointerpretation by Soilbank Composite and Site
Index Surveying, (Norwegian Realotment Surveying Jour-
nal nr. 4, 1957)," would be of interest to those asso-
clated with the subjects covered by Working Group No. 3.
Sweden:
From Sweden Captain Ragnar Thorén (2) reported on the
use of aerial photography in frost problems and pattern-
ed ground. Reporters Sven G. Môller, Hans Axelsson and
M. Jensen also submitted the following material on the
interpretation of surface configuration, drainage, soils,
and geology of Sweden:
The Geographical Institute of the Stockholm University
frequently applied studies and aerial PI at their scien-
tific research work. Their activity was in the first
hand concerned with geomorphology and glaciology. The
institute issued a couple of papers dealing with general
aspects of the subject and containing instructive ex-
amples of the indications which enable the Interpreter
to conclude.
The ground surface of Sweden is covered to a great
extent by quaternary deposits, which are the main con-
cern of practical studies at geological PI. So the
Swedish State Power Board and the Geological Survey of
Sweden used PI at the mapping of quaternary deposits,
but the aim and the methods vary in some degree.
Such maps were issued in print by the Geological
Survey of the province of Varmland, scale 1:200 000,
and similar maps covering the southern parts of the
province of Norrbotten are in preparation. The Geolo-
gical Survey 1s continuing their work with mapping of
the province of Jamtland. The working method of the
Geological Survey consists mainly of a preliminary study
of the aerial photographs in the stereoscope. As a re-
sult outstanding geological features were noted as a
lead for the subsequent field investigations, which are
performed in a widely spaced grid. At the assembly of
the field observations into a continuous map the aerial
photographs were studied more carefully resulting in
detailed boundaries between the various kinds of de-
posits in the region as for as warrented by the scale
of 1:200 000.
Other maps, scale 1:100 000, showing the contribu-
tary valleys of the upper Lule river in the province of
Norrbotten were printed by the State Power Board. The
extent of these maps, which is illustrated on the en-
closed map was confined to the river valleys by their
practical purpose, i.e. the search for suitable mater-
ials for the erection of earth fill dams and concrete
structures. The State Power Board is preparing for the
same purpose geological maps covering the valleys of
the Torne and Kalix rivers. The method of the State
Power Board is somewhat different from that of the Geo-
logical Survey. A draft map is immediately plotted as
a result of a detailed PI by stereoscope (Old Delft).
Simultaneously the pattern for the subsequent control-
ling field reconnaissance is planned and plotted. This
field reconnaissance is performed as a rule prior to the
final issue of the map whenever there exists some doubt
about the results from the results from the PI and is
usually also serving as a source for information concern-
ing the future work or as a training of the interpreter.
Several scales were used for the basic photographs be-
cause they usually were taken also for other purposes
than geological PI. It was found that the basic scale
for such work may not be smaller than 1:20 000, the most
Suitable scale being 1:15 000,
Occasionally large scale aerial photographs were used
by the State Power Board for geological PI whenever re-
quired and such large scale photographs were at hand
originally prepared for other purposes. This was mainly
the case at the geological PI of future dam sites and
when the tracing of future roads was studied. Especially
valuable geological information could be obtained by the
use of glossy-paper which results in prints of great de-
tail. A certain difficulty sometimes arises at the prac-
tical use of PI by the lack of a sufficient geological
knowledge by the planning engineer. Skillful geological
experts on the other hand will possibly find some diffi-
culty to transfer their complete findings to the planner
or to select for him all the details and all the aspects
of possible importance for the design.
The Geological Survey of Sweden announced the use of
bedrock PI in comnection with ore prospecting. At this
kind of work an attempt was made to analyze the min
features of the tectonics and the distribution of differ-
ent rock units.
PI was used when the detailed morphology of ravines
and landslide scars was studied at investigations into
Soil stability and river erosion problems. An interest-
ing application of this kind was the study of the land-
slide near the community of GSta at the banks of the Góta
river in June 1957, which could be performed by means of
photographs taken as well before as after the slide.
PI in a wider sense is often used by designing engine-
ers, who more and more study the topography directly in
stereoscopic models in order to get a visual impression
of the surface configuration, thus saving time and costs
for the otherwise inevitable drawing of contour maps.
As previously mentioned PI is used by the State Power
Board at road-planning, obtaining necessary geological
information. Simultaneously the topography is examined
and usually the final trace of the road can be decided
upon by means of Balplex models (model scale 1:2 000,
negative scale 1:8 000). As a first step of the design
a contour map is drawn with 5 m contour lines for a zone
on both sides of a preliminary trace. This map is gener-
ally not sufficient for the final tracing of the road,
but is a good help for the engineer when deciding the
final position in the above mentioned Balplex models.
The method is used mainly for the planning of heavy
traffic roads in waste territories.
Even private and government forestry authorities are
using PI for the planning of roads in forests. These
authorities are using stereoscopic methods only for the
general study of the topography whilst detailed road
planning would be done by traditional field methods.
Public roads are to a considerable extent planned with
photogrammetry by the Swedish National Road Board. This
authority is also using Balplex models for the choice of
such alternatives to be more closely examined among
geveral alternatives found only by stereoscopic methods.
This detailed planning of the finally chosen solution
however is made on a contour map drawn in an autograph.
Also in other fields of engineering more and more
direct studies in instruments of second and third order
were done. However, no new method of special interest
geems to have been originated in Sweden during the past
years.
The production of maps, which previously was done only
with field methods, is nowadays performed by means of
photogrammetry. In Sweden this is the case not only con-
cerning the official maps, i.e. the economical map,
scale 1:20 000, and the topographic map, scale 1:50 000,
but also special maps of various scales, which are being
