ABSTRACT
The geodetic methods give relative and also absolute displacements, as points of a structure can be observed from reference stations in the vicinity but outside the moving region. The methods of triangulation and traversing may be compared in advance with regard to their possible precision. Traverses for measuring displacements generally have a very regular shape. They approximate straight lines for movements in the terrain or in a straight tunnel; the check points are on a circle if they are situated in the gallery of an arch dam. The investigation of the precision of a displacement measured with a traverse may now be limited to the assessment of the influence of the precision of the angle and distance measurement. The precision alignment method may also be used for the measurement of long period vibrations in chimney stacks and church steeples.
