Applied surveying education : documenting cultural heritage in 3D in the city of Ghent (Belgium) using laser scanning and photo modelling

For several years the city of Ghent (Belgium) and the Ghent University, Department of Geography have been working together to document and measure important cultural heritage sites in 3D. The partnership enables master students in Geomatics and Surveying at the Ghent University to take part in a project driven measuring campaign. During the project, students use and compare several 3D data acquisition methods. This allows the students to implement their theoretical knowledge in the field. The used methods are analysed and critically compared by the students. Through this hands-on-training, students are encouraged to think “outside the box”. When problems occur, they are stimulated to think how these problems could have happened and most importantly how they can solve them. The documentation of these historic monuments in Ghent will be used during future renovation works and archaeological research. This paper will discuss the measurements in the Ghent City Museum (Stadsmuseum or STAM). The following methods are applied during the extensive field work: engineering surveying using total station and GNSS, photo modelling and laser scanning. The deliverables are created in a CAD or GIS environment. After successful completion of the course, students have gained a significant expertise concerning the processing of topographic data, 3D point clouds and imagery in an integrated way. This knowledge can be used after their studies to assess which equipment is most suitable for any given survey project. The final products of the photo modelling and the laser scanning process is a 3D model. Furthermore, digital elevation models and orthorectified images of the historic monument can be created. The orthorectified images are visualised and processed into high resolution orthophoto plans, in a CAD or GIS environment

Higher hydrography education in Belgium

In 2012, a 1-year, English spoken, curriculum degree of "Postgraduate in Hydrography" was started in Belgium as a cooperation between the Geography/Geomatics Department of Ghent University and the Institute for Hydrography of the Antwerp Maritime Academy, which is the hosting institute. Recent survey studies about hydrographic education in the Netherlands and in Belgium have pointed out a shortage in hydrographic training in these countries. Currently, the most active hydrographers in Belgium are engineers who received additional training within private companies. For the construction and implementation of the programme, a round table discussion was set up to assess the audience, procedures and desired outcomes for the industry. Relevant higher education institutes, governmental organizations and the maritime industry participated in this discussion. For reasons of flexibility and administration, a postgraduate programme was established, based on IHO (International Hydrographic Organization) standards for certification and quality. Apart from the compulsory courses, the emphasis lies on on-the-job practice with the partners of the industry to ensure maximum competence. An optimized flexibility is achieved by allowing any bachelor with a scientific background. All courses are lectured in English, and courses can be taken up over several years to facilitate part-time work. Furthermore, a selection committee has been installed to assess exemptions, in order to enable active hydrographers to study only the modules that are relevant for them. These procedures allow for a qualitative and professional yet accessible programme

Tunnel deformation measurements with high resolution laser scanning

Terrestrial high resolution laser scanning is a still growing technique for geodetic deformation measurements of civil technical constructions, i.c. newly built tunnels. By delivering millions of very accurate 3D points, laser scanning is an alternative for classical topographical measurements with a total station or digital photogrammetry for measurements in difficult field conditions. In the following paper, the error values during processing of a measured tunnel section and the final determination of the deformations of this tunnel section based on 3D laser scan point clouds will be further detailed. The results that are presented in this paper are results of measurements obtained with a terrestrial high resolution Time-of-Flight laser scanner Leica ScanStation 2. The subject of this research is the still ongoing construction of two railway tunnels in Zaventem (Belgium) as a northern access road for the national airport (Brussel Airport) (Diabolo-project, NV Infrabel). The twelve specified tunnel sections that have to be closely monitored, have to be scanned immediately after placement of the tunnel section, once a week during the first month after placement and once a month from then on until stabilization of the construction. The concrete surface of the walls is scanned with an average lateral resolu-tion of 5 mm. During the research until now, a workflow to determine the deformations of the tunnel sections is developed for processing the data with one laser scan software package (Trimble Realworks), followed by further analysis with a CAD software. The differences that are determined between the different points in time show a stabilization of the construction after the second control measurement. The comparison of the second control measurement with the previous control measurement shows a systematic and random error of less than 1 mm. Further improvement and extension of the workflow is planned in the near future, together with research on the correlation between the measured tunnel deformations and simultaneous measured tension measurements

Terrestrial laser scanning for tunnel deformation measurements

Terrestrial high resolution laser scanning is increasingly being used for geodetic deformation measurements of civil technical constructions, i.e. newly built tunnels. This paper deals with the error values during processing of a measured tunnel section and the final determination of the deformations of this tunnel section based on 3D laser scan point clouds