—h 
  
  
Mm 
STANDARDIZATION OF EXPRESSIONS FOR ACCURACY, DISCUSSION 
      
  
Discussion 
Professeur F. VANDERHEYDEN: Je remercie 
Monsieur Hallert pour le résumé qu'il vient de 
nous donner de son papier trés important que 
vous avez pu trouver, sinon pas lire, dans 
,,Photogrammetria". Je considére que ce rapport 
dans Photogrammetria est un peu chapitre d'un 
cours d'université de la théorie des erreurs et 
de l'étude de la précision. Aussi pour ce point 
nous remercions Monsieur Hallert d'avoir rédigé 
ce rapport. 
A- la différence de ce que Monsieur 
Schermerhorn avait en vue, notamment de faire 
une proposition sans l'espoir qu'elle soit adop- 
tee, Monsieur Hallert veut aller plus loin. Il 
voudrait que sa proposition serve de base pour 
une classification des terms, une terminologie 
qui soit acceptée. Il est évident que nous ne 
pouvons pas ici décider si oui ou non cette pro- 
position qu’il fait dans son rapport est accep- 
table ou non, et si nous sommes tous d’accord 
pour dorénavant la suivre. Je suis même sûr 
que dans la salle il y a des personnes présentes, 
je regarde Monsieur Baetslé, qui déjà dès main- 
tenant ne sont pas d'accord. Mais la question 
que je me pose est la suivante: Est-ce que nous 
ne ferions pas bien d'accepter la proposition 
faite en final par Monsieur Hallert de désigner 
quelques personnes qui voudraient bien se 
réunir ou bien s'écrire en vue d'arriver à une 
entente. Je suis sür que Monsieur Hallert a dans 
la téte quelques noms qu'il pourrait proposer 
pour ce groupe de travail, mais je voudrais 
d'abord savoir si la salle me suit dans cette 
proposition. 
Prof W. SCHERMERHORN: I should like to say 
a few words because there is some misunder- 
standing about what I have said. The intention 
was not that it would not be adopted. I am afraid 
that if we adopt it, it will have very limited 
consequense in use. I think our proposal is the 
same as that of Mr Hallert. It is very nice to 
introduce definitions. However, I would draw 
attention to the fact that more important than 
standardisation in this respect is the fact that we 
should have a set of clear-cut definitions in 
different languages, so that we can derive the 
exact meaning from these when a certain ex- 
pression is used. That is important. I believe 
that all efforts to press theories into the same 
frame will fail. Our job is to get definitions in 
different languages and compare them. That is 
necessary. Such a joint commission, whatever 
they have in mind, either the one or the other, 
should aim for the best result being of the ut- 
most importance. All this kind of work is very 
difficult and takes a long time. If you try to get 
everybody in the same position and standardise 
more or less, then I am sure that nothing will 
come out. The only important thing is that we 
understand each other’s language. That is im- 
portant and it is something which is missing in 
photogrammetry, as Mr Hallert has said. I fully 
support him. 
Prof F. VANDERHEYDEN: Do I understand 
that you are against the commission? 
Prof W. SCHERMERHORN: No, but I want to 
tell the audience that there are two different 
lines of thinking in this respect, and that we must 
carefully consider which kind of task such a 
joint commission will receive: whether it will be 
an effort to give a definition in the various 
languages as to the meaning of the words or 
whether we must all try to talk the same 
language. I do not consider the latter possible 
when we are dealing with such theoretical prob- 
lems. I think we should start by knowing what 
we are talking about; that is already difficult 
enough. I propose that this should be the first 
task of such a joint commission and then we 
could look at it again after that. 
Mr B. HALLERT: I agree with Professor 
Schermerhorn, and I am very grateful to him for 
supporting what we have been talking about 
here. 
It could be mentioned that there are about 
fifteen or sixteen different expressions for accu- 
racy in use today. I have listed them here but I 
have not time to read them. You have the ex- 
pressions “the accuracy of", "the precision of" 
and "the uncertainty of" which contain all these 
fifteen expressions. That is something we could 
start with. My proposal is that we should have 
a joint commission between Union Géodésique, 
the ISP and the FIG which I proposed in 
Delft in 1958. I think we could give the new 
President of Commission II the task of getting 
into contact with the other organisations. I 
believe our own Society should create a group 
which, in my opinion, should consist of the 
following names — and it is important here that 
we get the different languages represented — 
Professor Bachmann in Switzerland for the 
German and for the French; Dr Schmid in the 
United States for the German and for the 
English; and Professor Roelofs in Holland for 
the Dutch. I do not know whether you would 
agree to this; it is up to you. 
  
  
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