Application of boat‐based laser scanning for river survey

Abstract

The boat-based, mobile mapping system (BoMMS) with a laser scanner allows the derivation of detailed riverine topographical data for fl uvial applications. Combined with data acquisition from static terrestrial LiDAR (light detection and range) or mobile terrestrial LiDAR on the ground, boat-based laser scanning enables a totally new fi eld mapping approach for fl uvial studies. The BoMMS approach is an extremely rapid methodology for surveying riverine topography, taking only 85 min to survey a reach approximately 6 km in length. The BoMMS approach also allowed an effective survey angle for deep river banks, which is diffi cult to achieve with aerial or static terrestrial LiDAR. Further, this paper demonstrates the three-dimensional mapping of a pointbar and its detailed morphology. Compared with the BoMMS surface, approximately, 80% and 96% of the terrestrial LiDAR points showed a height deviation of less than 2 cm and 5 cm, respectively, with an overall standard deviation of ± 2·7 cm. This level of accuracy and rapidity of data capture enables the mapping of post-fl ood deposition directly after a fl ood event without an extensive time lag. Additionally, the improved object characterisation may allow for better 3D mapping of the point bar and other riverrine features. However, the shadow effect of the BoMMS survey in point bar mapping should be removed by additional LiDAR data to acquire entire riverine topography. The approach demonstrated allowed a large reach to be surveyed compared with static terrestrial LiDAR and increased the spatial limit of survey towards aerial LiDAR, but it maintains the same or even better temporal resolution as static terrestrial LiDAR.

Investigating the geomorphological potential of freely available and accessible structure‐from‐motion photogrammetry using a smartphone

“…Over the last decade, terrestrial laser scanners proved capable of generating very high quality DEM data (e.g. Heritage and Hetherington, 2007;Alho et al, 2009;Hodge et al, 2009a,b;Schaefer and Inkpen, 2010) and have almost become routine in some DEM collection strategies. However, they remain relatively expensive items of technology and have only recently become truly portable.…”

Mapping Topography Changes and Elevation Accuracies Using a Mobile Laser Scanner

“…After the integration of a scanning mechanism with lidar and an inertial measurements unit with GPS in the early 1990s, it has been possible to use first airborne laser scanning (ALS), then MLS data, in addition to static based terrestrial laser scanning (TLS), to improve the measurement and modeling of fluvial environments (e.g., [2][3][4][5][6][7][8][9][10][11][12]). High-resolution ALS provides detailed information on topographical features of fluvial environments that influence the river hydraulics, giving, therefore, the potential to improve existing hydraulic models (e.g., [13][14][15][16][17]).…”

“…The improved topographical data allows for better planning of the management of river hydraulics and erosion control (e.g., [14,18]) and better analysis of different flooding scenarios [16]. Alho et al [11,19] showed that MLS offered a very effective method for surveying riverine topography compared to traditional TLS. In that study, 6 km of riverine topography was surveyed by the boat-mounted mobile laser scanner within 85 min, whereas TLS measurements of the point bars of the same area took over 8 hours.…”

Terrestrial Laser Scanning Reveals Seagrass Microhabitat Structure on a Tideflat

“…This limited our useful scan radius to approximately 50 m. Our implementation of TLS afforded sufficient mapping extent to address the questions of our study, but would not be suitable for larger mapping projects. Some researchers have extended the useful range of scans by elevating the scanner to considerable heights above the sediment surface, e.g., [24], and recently, by developing mobile TLS platforms, e.g., [43].…”