Job
For the heritage-protected reconstruction of an ancient industrial building in Magdeburg (Germany), 3D laser scanning has been applied as method of measurement. The survey of three facades of the mentioned building was accomplished via laser scanner and the analysis and interpretation of data by means of the software PointCab and Geograf on a scale of 1:50.
Target
In the scope of restoration works and renovations, 22 loft apartments shall be created in the complex. For an authentic reconstruction of the facade as part of the renovations, detailed and accurate façade plans, which are true to scale, are necessary. As a result of the space restrictions, the 17 m high façade can only be imaged by a contact-free measuring technique. A highly accurate dimensional as-built-documentation is essential for getting precise plans as a basis for planning.
Survey
From 25 laser scanner positions, a total of 1.720 m² facade has been measured, thereof 469 m² façade are on the yard side, 442 m² on the east side and 810 m² of the street view. The smallest of the three facades, the east façade, is fitted with several jumps in the façade and inclined façade components by which the effort for the survey as well as for the analysis and interpretation is increased. By laser scanning, the façade details, such as window opening and breaks in the wall, could be captured in high accuracy.
The whole survey has been realised by just one assistant within ca. 5 hours. Thus, the expense of the field work has been reduced significantly by laser scanning.
Analysis and Interpretation
The orthophotos have been generated automatically from the laser-scanning measurement results in the Laserscanning Europe software PointCab. Although the scan data was about 3 GB, the analysis and interpretation took only one hour.
Due to the scaled images in PointCab, the data could be analysed and interpreted within ca. 30 hours in the CAD system Geograf. The analysis and interpretation resulted in detailed orthophotos and structured digital 2D plans of the facade, including the jumps in the east facade. Additionally, the customer received a point-cloud viewer, with which measures can be picked out of the laser-scanning data afterwards, for free. Now, modelling can be carried out in the generated views and cut sections of the 3D CAD model whereby planning for the restoration works and renovations is simplified.
Thus, 3D laser scanning is applied more and more frequently in the field of architecture and monument protection. Furthermore, this method makes it possible to complete area calculations and expense budgeting exactly.
