SI2017-E-2: Mapping seamless elevation using topo-bathymetric lidar – Tim Webster, Kevin McGuigan, Nathan Crowell, David Colville

Applied Geomatics Research Group, NSCC, Middleton
Centre of Geographic Sciences, NSCC, Lawrencetown

The coastal zone is a challenging place to map. Techniques for mapping the land cover and elevation do not work under water and methods for mapping the seabed cover and elevation work well in deep water but are dangerous and expensive in shallow water. As a result, detailed information in the shallow coastal zone and other freshwater aquatic environments is lacking. This presentation will focus on the Leica Geosystems Chiroptera II, a new shallow water topo-bathymetric lidar sensor that is designed to collect seamless elevation data from land to the submerged terrain under water. The sensor is equipped with a 1064 nm laser capable of a laser scanning frequency up to 500 kHz and a 515 nm green laser capable of a scanning frequency of 35 kHz. In addition to collecting the elevation at high resolution ~ 1m and vertical precision ~ 15 cm, the intensity of the reflected green laser also provides insights into what is on the seabed. A 60 MPIX RCD30 camera capable of capturing NIR and RGB bands of imagery is co-aligned with the lidar sensor to provide additional data that can be directly georeferenced with a ca 5 cm resolution at 400 m altitude, typical for bathymetric surveys. NSCC-AGRG has conducted topo-bathy lidar surveys throughout Maritime Canada for the past 3 years using this sensor. Various applications of these data will be presented including mapping submerged aquatic vegetation, providing input to hydrodynamic model simulations to support aquaculture site selection and improve oil spill preparedness, and shoreline sensitivity mapping.