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Figure 2: Definition of work parameters 
The sequence of work is predetermined. The parameters of the work are essential for the amount and quality of results to be achieved 
during the project. Among these parameters some are also predetermined, like the available resources of manpower, skills, 
equipment, funding and last but not least time. Others are flexible, like the methods to apply, the distribution of control points, 
drawing scales, projection or section planes, image scales, views and orientations and many others. It is the task of the project 
management to optimize the parameters of work to extract the best possible results under the given restrictions. Besides the given 
general conditions the proposed results determine the work parameters. Therefore the flow of conditions defining the work 
parameters is vice-versa to the work flow (Fig. 1 and 2). The proposed results determine the data to acquire, this data determine the 
field work to be carried out during the campaign, what again has an influence on the necessary preparations. 
2. DEFINITION OF WORK PARAMETERS 
There is a lot of parameters to be planned in the preparation of the field campaign. The definition of work parameter belongs to the 
most important questions. The primary results of documentation process are interpretations projected as overlays on geometrically 
exact representations. The usual form of representations for the analysis of the documentation even nowadays are views or vertical or 
horizontal sections through the object projected onto a planar surface. They are also the common form for the publication, as many 
persons have no access to the required technology or are not familiar to the handling of newer forms like 3D models (CAD or 
VRML). To avoid gaps in the planar representations it is recommended to consider the planned sections through the object as early as 
possible, e.g. during definition and realization of the site covering control network. 
2.1 Control Network 
The control network consists of ground points, where the instruments will be placed and control points at the object. It is useful to 
place control points such a way, that they can be used for multiple purposes. The control points will be used: 
• as definition points for horizontal or vertical sections through the object 
• as anchor points for manual measurements 
• as fix points for free stations during the tacheometric survey 
• as photogrammetric control points 
• as order points for the assignment of images 
It is recommended to use signalized points if it is 
possible. If signalized points can be used, the marks 
should be resistible against adverse weather 
conditions, playing children and other environ 
mental influences. It has to be possible to remove 
the marks without traces at the object. To avoid 
point mismatches it is useful to show the point 
number on the marks. This is of high importance if 
more than one team is working at the object. 
Natural points have to be defined as control points if 
no signalized points can be placed due to 
conservational reasons or limited accessibility. They 
have to be documented in a non-ambiguous manner. 
Their names and definitions have to be delivered to 
all measurement teams. The probability of errors 
due to point mismatch or non-precise measurements 
is much higher than with signalized control points. 
The number of control points has to be sufficient for 
their tasks, but the required measurement work has 
to be justifiable. 
Figure 3: Geodetic measurement of the control network