Three-dimensional (3D) as-built reconstruction from laser scanning dataset

As built surveying is a survey technique where position and geometrical attributes are observed and presented in a survey plan. Three- dimensional reconstruction from geoinformation discipline has the advantage to improve the measurement of an as built building. Modern as built reconstruction has less limitation compared to conventional as built surveying. The objective of this study is to validate the accuracy of point cloud measurement and traditional as built data. Terrestrial laser scanner was used to record all interior and exterior spatial and geometry data of a building. A rendered 3D model of the scanned data was developed to provide semantic information of the building. The result shows that geometrical measurement of an as built model from point cloud data has good accuracy. As conclusion, the point cloud data is suitable to be used for as- built reconstruction which improves as-built surveying practice

Quality assessment of terrestrial laser scanner surface deviation analysis in vegetation slope monitoring

Mechanised with ability to rapidly acquire three-dimensional (3D) data using non-contact measurement, terrestrial laser scanner (TLS) has become an option in landslide monitoring. Dense 3D point clouds provided from TLS has enable surface deviation analysis to rigidly examine the displacement that occurred on the monitored object. However, the existence of vegetation on land slope has become uncertainty in TLS measurement for landslide monitoring. To concretely measure the effect of vegetation, this study has performed two epoch landslide monitoring using tacheometry (for benchmarking) and TLS (Topcon GLS-2000) at Kulim Techno City, Kedah, Malaysia. Sixteen (16) artificial targets were well-distributed on the slope to determine the accuracy of the employed TLS, evaluate the capability of TLS to determine the stability of the slope and scrutinise the significant of vegetation uncertainties in TLS measurement. Results obtained revealed that Topcon GLS-2000 manage to obtained results that are statistically similar to tacheometry and provides 0.006m of accuracy. However, the presence of high incidence angles in TLS measurement has limited the capability to identify the significant displacement of the targets. With the aid of F-variance ratio test, the study has statistically proved that vegetation uncertainty is able to decrease the quality of TLS data.Landslide monitoring, Quality assessmen