NV5 Geospatial’s passion and commitment to innovative unmanned aerial systems (UAS) makes us an industry leader in data acquisition, processing, and downstream analytics.
We are the largest, most innovative, and most capable geospatial solutions firm in North America. We use our scale to the advantage of our clients, providing efficiencies and analytics that aren’t typically seen in our space. We are the geospatial pioneer pushing the boundaries of data and analytics to deliver actionable intelligence to transform the way our clients utilize and value geospatial data
Topobathy Lidar Defined
Topobathymetric lidar is the science of simultaneously measuring and recording three distinct surfaces – land, water, and submerged land using airborne laser-based sensors. While this technology shares a lot with the traditional airborne lidar mapping of the terrestrial landscape, there are also significant differences and major challenges introduced. Topobathymetric lidar sensors use two independent laser sources to acquire the raw data needed to accurately map the three surfaces. A near infrared laser is used to map the land and surface of the water. This light is both absorbed and reflected by the water and provides an accurate representation of the location and shape of the water surface. A visible green laser is required to penetrate the water surface and make measurements of
the submerged land below.
Topobathymetric lidar has many important applications. These include:
• Shoreline and coastal intelligence • Habitat restoration • Floodplain modeling • Volumetric analysis • Infrastructure planning and engineering • Coastal zone management
This specialized capability allows you to greatly increase your knowledge of the nearshore environment for improved marine resource mapping, benthic habitat mapping, shoreline delineation, nautical charting, and marine debris mapping.
Moreover, Topobathymetric lidar also provides the ability to seamlessly map stream channel morphology, floodplain topography, habitat connectivity, and riparian vegetation with unprecedented detail. This technology has advanced our ability to comprehensively map dynamic floodplains to guide inundation modeling; dam and canal infrastructure evaluations; and river and watershed restoration efforts.
Finally, we can now provide important baseline data to support engineering and planning for dam removal projects; pipeline and telecom infrastructure; and road and rail crossings.
One crucial question for any topobathymetric lidar project is the maximum achievable depth of mapping. The answer is highly dependent on project conditions, most notably water clarity and bottom reflectance. We use available resources to understand water clarity dynamics in the project area including local knowledge, real-time monitoring stations, and available satellite and aerial imagery. This informaiton is used to plan data collection under optimal conditions and predict depth performance of the sensor.
We measure local water clarity at the time of flight and quantify that numerically using a standard black and white disk (known as a Secchi disk). The recorded Secchi depth is the depth at which our eyes can no longer see the disk as it is lowered into the water. The green laser sensor is more sensitive than the unaided eye and typically maps to 1.5 or more times this depth.
Overall, we frequently capture depths in riverine systems from two to five meters, or more. In the highly variable nearshore coastal environments, the mapped depths can range from three to five meters along the Atlantic seaboard, to twenty or more meters in the Florida Keys or Caribbean where the water clarity is near ideal.