A Comparison of High-density Linear-Scan Lidar to Geiger-mode LiDAR in Heavily-Vegetated Habitats in Florida
Dense vegetation, year-round “leaf-on” conditions, and high annual rainfall in Florida presents many challenges to aerial laser topographic mapping. When those normal challenges are further stressed by high point-density mapping requirements, linear sensors, when flown with high flightline overlap, or Geiger-mode sensors, offer possible, alternative solutions. The Southwest Florida Water Management District (SWFWMD), the Hillsborough County Board of County Commissioners (BOCC), and the City of Tampa (COT), cooperatively funded a high-density linear scan LiDAR acquisition mission in the winter of 2017. Later that year, Harris Corporation, planned to obtain high-density Geiger-mode LiDAR over a portion of the mission.
After securing the use of the VQ-1560i directly from Riegl Inc., Dewberry planned and executed a mission to obtain an Aggregate Nominal Point Density (ANPD) to exceed 20 points/square meter. To accomplish this density, the flight plan called for a 60% overlap at an altitude of 4300 ft AGL, and flight speed of 120 knots during day and night time operations. Harris Corp. collected Geiger-mode data over a 12-square mile portion for comparison at 50% overlap at an altitude of 12,900 feet, and flight speed of 250 knots during night time operations only and was processed to exceed 20 ANPD for direct comparison to the Linear technology.
Pending Harris’ successful Pilot mission, this presentation discusses the flight acquisition and data processing considerations to meet the SWFWMD specifications and data accuracy requirements as well as compares the LiDAR penetration and point densities achieved through the vegetation by these technologies. The benefits and caveats of dense LiDAR mapping in challenging environments will also be discussed.