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PHASES AND SCALES
1. Classification of phases and scales
Nearly all those interviewed agreed upon this next division of phases:
- exploratory
— reconnaissance
- semi-detailed
— detailed
(project design)
We can add to this that the exploratory phase is normally not a field survey,
but a phase that can be done in the office. The data needed for this phase
can in most cases be derived from literature. In some areas this can even
apply to the reconnaissance phase. All 16 experts had the consensus of opin-
ion that the phases mentioned are in a logical sequence, and that in general
no detailed survey should be undertaken before the prececding rhases have
been done. The project design rhase as mentioned in the questionnaire was uot
unanimously seen as a survey phase, but as a logical result of the preceeding
survey phases, As such it is justifiable to mention it in the list of dif-
ferent survey phases,
It emerged that a certain survey phase could clearly be correlated to a cert-
ain scale. The following scales were considered acceptable:
- exploratory phase ..... smaller than 1:500.000
- reconnaissance phase ,.. 1:100.000 - 1:500.000
— semi-detailed phase ... 1:25,000 - 1:100.0CC
- deisiled phase ........ larger than 1:20.000 (or 1:25.000)
- project design ........ larger than 1:10.000
2. Publication scale - survey scale.
The publication scale (unanimously defined as the scale on which the map
is printed or mimeographed for the final report) was considered to be es-
sentially different from the survey scale. Publication scale is in general
about a factor 2 smaller than the survey scale. Reduction of the survey sca-
le is applied because otherwise the map would suggest a higher precision
than is scientifically justified. For the sociologist and the economist re-
duction of the survey scale was not a scientific, but a purely cartographic
and typographic affair (the scale to be reduced as far as possible).
3. Factors determining phases and scales
The answers to ihis rather difficult question could be summarized as follows:
a. It is important that the survey phases should be in a logical sequence,
e.g. from exploratory to detailed. No detailed surveys should be done
before the foregoing phase has been carried out or before its equivalent
is known from literature. This means also that the information (litera-
ture) already existing of a certain area is an important factor for the
decision of the survey phase.