TACTILE SURVEYING METHODS OF SURVEYING BUILDING DETAIL -
AN ESSENTIAL COMPONENT OF COMPUTER-AIDED BUILDING SURVEYING
U. Weferling
Bauhaus-Universität Weimar, Chair Computer Science in Architecture
ulrich.weferling@archit.uni-weimar.de
Working Group 6
KEY WORDS: tactile surveying of building detail, consistent computer-aided building surveying, AR/VR
ABSTRACT:
Computer-aided tacheometry and photogrammetry are used increasingly for surveying building geometry. The use of manual
methods such as tape, measuring-stick or laser-distance meter are equally widespread for buildings as long as the building geometry
is reasonably simple.
However the surveying of building elements with complex geometries (such as a column capital or gothic window) is difficult to
integrate in computer-aided surveying systems.
This paper proposes a building surveying approach for this neglected area that employs tactile object surveying in combination with
classical methods of tacheometry and photogrammetry and so makes the most of both methods.
1. INTRODUCTION
In most cases the term building surveying is usually understood
as the geometric measurement of the building in plan, section
and elevation. For planning or research purposes a whole series
of supplementary information is required and typically the
amount of information required increases and becomes more
specific as planning or research progresses (Petzold, 2001).
A geometric survey is undertaken using geodetic or
photogrammetric measurement systems which have been
tailored to the needs of building surveying. In general these
necessitate a degree of technical knowledge and not least
financial resources. The integration of new technologies such as
photogrammetry and tacheometry in an integrated surveying
approach together with manual measurement techniques
compensates for the main weaknesses in traditional surveying.
However two fundamental problems still remain:
A large proportion of measurements do not occur in direct
contact with the building which means that some
information will not be noticed, and
the integration of new technology through an intelligent
software system does not simplify the use of the measuring
equipment itself.
In addition a further element is not considered in the traditional
up-front survey: the need for increased and more detailed
specific information during the course of research or planning
process.
This paper looks at the use and systematic integration of tactile
surveying methods for geometric surveying in direct contact
with the building. The essential characteristics and deficits of
traditional measurement approaches will be investigated as a
basis for developing a simple concept for surveying building
detail. Finally, possible means of implementing such a concept
using existing tactile measurement systems will be examined
and assessed.
2. TRADITIONAL MEASURING TECHNIQUES
Traditional building surveying using conventional measuring
techniques is oriented around producing analogue
documentation in the form of plan, section and elevation.
Conventional methods include manual surveying by hand,
reflector-less tacheometry and photogrammetry. These methods
have been further developed to suit the IT demands of current
planning and renovation practice (Donath et al, 2002).
2.1 Computer-aided manual surveying
Computer-aided manual surveying using an electronic distance
meter is the simplest way of quickly and cheaply measuring
spatial geometry. The following characteristics can be
identified:
The measurement occurs in direct contact with the building.
The measurements are taken between two surfaces (length
of a wall, room height, door width etc.) which the distance
meter is held up against.
There is a minimum distance measurable, depending upon
the distance meter.
Measurements can only be taken between two points in
direct visual contact with one another.
Simple spatial constellations (primarily with even surfaces)
can be measured reasonably effectively and efficiently.
2.2 Reflector-less tacheometry
Besides computer-aided manual surveying a common method is
the use of reflector-less tacheometry. Despite its adaptation to
the requirements of planning there are still a number of
disadvantages associated with reflector-less tacheometry:
The direct contact with the building is lost.
There must be a direct visual connection between the
equipment and the point to be measured.
