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STANDARDIZATION OF EXPRESSIONS FOR ACCURACY, DISCUSSION 177
Prof F. VANDERHEYDEN: What is the feeling
of the audience about this?
Mr A. M. WASSEF: 1 should like to make a
small remark on that issue. The International
Association of Geodesy has already established
a special study group to go into the questions
of statistics and geodesy. It is part of the work
of that group to establish the terminology and to
make sure that when we specify precision we
know exactly what we mean by it. One of the
things we have found out is that when we talk
about accuracy it means absolutely nothing. We
should specify the standard error. When we
have specified the standard error, we should
then give the value of the standard error together
with the number of degrees of freedom on which
the derivation of the standard error was used,
otherwise the value of the standard error would
mean very little.
There are other things also connected with
the same problem: for instance, the classifica-
tion of errors into systematic errors and acci-
dental errors. In photogrammetry we have
pseudo systematic errors and a variety of other
errors. The whole thing is very confusing. We
could knock out the words “accidental” and
"systematic" and talk about errors only. We
classify the errors by the way they were derived.
For instance, we might say that the error which
is within, say, the model or the error which goes
from one model to another model, or something
like that, is quite adequate for the classification
of errors. It gives us a more or less homoge-
neous system. However, nevertheless, the ques-
tion of systematic and accidental errors still
hangs over us.
Prof F. VANDERHEYDEN: I think Mr Hallert
will answer you.
Mr B. HALLERT: I think the commission
which I have proposed should contact the com-
Archives 4
mittee you have mentioned and also the FIG
under the supervision of the new President of
Commission II.
Professeur P. BAETSLÉ: J'ai demandé à
Monsieur le professeur Hallert d’inclure dans sa
commission quelqu'un de France pour une
terminologie certaine en frangais, sans vouloir
diminuer le moins du monde les mérites de
Monsieur le professeur Bachmann qui est ici à
côté et qui a été cité comme étant celui qui
pouvait fonctionner dans ce but, étant donné
qu'il est polyglotte — et il est trés intéressant
d'avoir des polyglottes — mais du point de vue
de la terminologie reçue je pense qu'il est bon
d'avoir quelqu'un représentant l'école frangaise.
Je ne sais pas, je voudrais demander s'il y a
quelqu'un qui peut. . .
Professeur F. VANDERHEYDEN: Eh bien,
je propose donc que cette petite commission
sous la présidence du futur président de la Com-
mission II, fonctionne et prenne contact avec
les deux autres commissions analogues qui ont
déjà été créés dans ce but, et táche d'arriver
pour le prochain Congrés à un accord, ou si
possible méme avant.
Prof R. RoELors: Mr Hallert has already
pointed out that this question of collaboration
between the three Societies mentioned was
raised in 1958 in Holland at the Congress of the
FIG. As an outcome of this discussion in 1958
in Holland the FIG sent letters to other organi-
sations — that is the Union and this Society — in
order to ask for their co-operation and to ask for
the formation of commissions within these
Societies. We have established a certain contact.
Therefore, I think the initiative has already been
taken, and what we have to do is just to step in.
Prof F. VANDERHEYDEN: That settles the
question.
