Equipment Considerations for Terrestrial Laser Scanning for Civil Engineering in Urban Areas

When renting or purchasing a terrestrial laser scanner, consideration must be given to a variety of factors including ease of use, accuracy, speed and cost. The following paper considers these aspects with respect to civil engineering applications in urban areas. One particular concern relates to the logistics of being in the field in terms of the equipment quality, the required space, power supply needs, and time needed for operation. Other factors relate to data acquisition, quality, and processing. To illustrate these issues, two terrestrial laser scanners (one from 2003 and one from 2013) were used to acquire a point cloud of three, masonry building facades in a dense urban setting. Also, sample solid models as required for computational modelling in civil engineering, were generated from these scan data sets. The resulting investigation showed that despite a 10-year age difference in the units, there was no appreciable improvement in the scan angle accuracy, and data from both units was successfully employed to reconstruct building models for computation. However, the newer scanner was significantly faster in data acquisition and possessed other features that made it easier and more effective to deploy in urban areas, where space is limited and vehicular and pedestrian traffic can be problematic. The paper also provides a cost comparison of the two units showing that financial competitiveness depends upon the workload. This paper provides information for firms considering purchasing, renting, or subcontracting laser scanners for civil engineering projects in urban areas.