157 
SUB-COMMISION IV-3 
SMALL-SCALE MAPPING 
President: Mr T. J. Blachut (Canada); Mr C. Broillet (Europe) 
Presentation of the General Report of Sub-Commission IV-3 
in the Meeting held on Wednesday, 7th September, 1960 
by the President, Mr Blachut 
With your permission I will skip my report 
on the situation in the “Small-scale Mapping” 
during the last four years, because my report 
has been published and there is not much new 
development. In view of the very short time I 
would prefer to describe some of the results of 
our experimental work. 
I would also prefer to start immediately with 
some comments on our experimental work. 
However, as it has been stressed, human prob- 
lems even in our association should not be for- 
gotten and I would like to mention a few facts 
which I think are of importance. 
First of all, the activity of Sub-Commission 
IV-3 has been conducted by myself and I have 
been helped by my colleagues, Mr Broillet from 
Switzerland, Mr Tewinkel, who conducted in- 
dependently the analysis of the accuracy of con- 
touring, and by Professor Finsterwalder, who 
was kind enough to analyse certain aspects of 
small-scale mapping. It is unfortunate that Mr 
Tewinkel is not present and so will not be able to 
address you. Professor Finsterwalder will say a 
few words. 
I would like to draw your attention to the 
fact that all the reports have been published, 
first in the Canadian Surveyor in the May issue 
of this year and then they have been distributed 
at this Congress. 
I should not forget also to mention the 
participants, who are, of course, most important 
in this kind of work. Judging by the number of 
participants and the number of submissions we 
have been extremely successful this time and I 
would say that the problem of our investigation 
work was of interest. Altogether we had 38 
submissions from about 28 photogrammetric 
centres. It was also the first time that some of 
the Asiatic countries participated in this ex- 
periment and they produced most encouraging 
results; I would like to congratulate them for it. 
I will now try to describe very shortly the 
aim of our experimental work and the most im- 
portant results. It has been established in 
Canada, it consisted of one single overlap made 
out of the photographs, one to fifty thousand. 
Archives 5 
It was the decision of our Commission, ap- 
proved at a meeting in Brussels, that we should 
restrict our research to limited scope, in order to 
be able to answer properly some questions. This 
material, a photograph of the test area, has been 
prepared very carefully and distributed among 
the participants only after all control points and 
all control elements have been checked. The 
participants were requested to submit the 
results, the results have been analysed and sent 
again to the participants, so each single partici- 
pant had occasion to express his opinion, which 
helped us very much to straighten out certain 
misunderstandings which always exist and are 
very difficult to avoid. After we received the 
comments we published the results and they can 
be found in the report. 
The technical aim of the investigation was 
to try to find out the source of systematic errors, 
which have been very evident from the first 
international mapping experiment. We had pre- 
vailing positive and sometimes negative errors 
and we did not know from where they came. 
Secondly, we hoped again to be able to throw 
some light on the efficiency of the certain type 
of equipment used and we particularly wanted 
to compare an anaglyphic type plotter with 
other plotters. 
As a result I think we can state that the 
photogrammetric accuracy at the present time is 
much better than we assume generally under the 
condition that we treat properly the photograph- 
ic material. By this statement I mean not only 
the treatment of the photographs but also proper 
plotting procedure on the machines. We found 
that the biggest errors were caused not by any 
failure of the equipment or of the photographic 
material, but just by improper operation. 
Secondly, we found out that there were re- 
markable, astonishingly high, personal errors 
of physiological and probably psychological 
character. We carried out quite extensive in- 
vestigations which, I think, at least indicate that 
there is a necessity for more extensive investiga- 
tions in this particular field. According to the 
figures, which of course are limited, it seems that 
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