ABSTRACT
Garcia-Williams, I.A.; Starek, M.J., and Berryhill, J., 0000. Development of an optimized survey workflow for sandy beaches with mapping-grade mobile LIDAR.
Mapping-grade mobile LIDAR scanning (MLS) systems have increasing appeal for coastal surveying, because they are becoming more cost effective and compact in comparison to the more expensive, higher-caliber, survey-grade MLS systems. Despite the misconception that these systems are plug and play, they should be evaluated, and sources of error must be understood to generate consistent, accurate data. This study assesses a miniaturized, mapping-grade MLS system to develop an optimized, validated survey workflow for rapid coastal corridor mapping of sandy beaches. The MLS system, called the HiWay Mapper, integrates a Velodyne HDL-32E LIDAR scanner, a NovAtel inertial navigation system, and a FLIR Ladybug 360° spherical camera. A four-part framework is introduced, in which a series of rigorous experiments were conducted to evaluate and validate system performance to generate a repeatable workflow for collecting high-accuracy, three-dimensional point cloud data of sandy beaches and foredunes. The framework of (1) sensor characterization and setup, (2) quality assurance, (3) data processing and quality control, and (4) postprocessing will ultimately support the production of georeferenced digital elevation models (DEMs) to monitor geomorphology changes of sandy beach and foredune systems. The final workflow was evaluated on a 4-km stretch of sandy beach on Padre Island National Seashore, Texas. Two surveys were completed on 26 July 2022 and 22 September 2022 to provide examples of workflow repeatability and vertical root-mean-square error (RMSE) measures. The final DEM vertical RMSEs were 0.039 and 0.037 m, respectively. Cross-shore transects were also used to extract metrics to compute shoreline movement, beach width, dune slope, and beach slope to show seasonal dynamics. The experiments, results, and workflow presented herein, along with guidance, should benefit coastal researchers seeking to integrate mapping-grade MLS systems into their data collection workflow.
