EAARL-B Submerged Topography—Barnegat Bay, New Jersey, pre-Hurricane Sandy, 2012

American Standard Code for Information Interchange XYZ and binary point-cloud data, as well as a digital elevation model for part of Barnegat Bay, New Jersey, pre-Hurricane Sandy (October 2012 hurricane), were produced from remotely sensed, geographically referenced elevation measurements by the U.S. Geological Survey. Elevation measurements were collected over the area using the second-generation Experimental Advanced Airborne Research Lidar, a pulsed laser ranging system mounted onboard an aircraft to measure ground elevation, vegetation canopy, and coastal topography. The system uses high-frequency laser beams directed at the Earth's surface through an opening in the bottom of the aircraft's fuselage. The laser system records the time difference between emission of the laser beam and the reception of the reflected laser signal in the aircraft. The plane travels over the target area at approximately 55 meters per second at an elevation of approximately 300 meters, resulting in a laser swath of approximately 240 meters with an average point spacing of 0.5-1.6 meters. The nominal vertical elevation accuracy expressed as the root mean square error (RMSE) is 20 centimeters. A peak sampling rate of 15-30 kilohertz results in an extremely dense spatial elevation dataset. More than 100 kilometers of coastline can be surveyed easily within a 3- to 4-hour mission. When resultant elevation maps for an area are analyzed, they provide a useful tool to make management decisions regarding land development.

美国信息交换标准代码（American Standard Code for Information Interchange）格式的XYZ坐标点云数据与二进制点云数据，以及新泽西州巴内加特湾部分区域在2012年10月桑迪飓风发生前的数字高程模型（digital elevation model, DEM），均由美国地质调查局（U.S. Geological Survey, USGS）通过遥感地理参考高程测量数据生成。该区域的高程数据采用第二代实验先进机载研究激光雷达（Experimental Advanced Airborne Research Lidar, EAARL）采集——这是一款搭载于飞机平台的脉冲激光测距系统，可用于测量地面高程、植被冠层及海岸地形。该系统通过飞机机身底部的开孔向地球表面发射高频激光束，机载激光系统会记录激光束发射与接收反射激光信号之间的时间差。飞机以约55米/秒的速度、300米左右的飞行高度飞越目标区域，由此形成的激光扫描带宽约240米，平均点间距为0.5~1.6米。以均方根误差（root mean square error, RMSE）表征的标称垂直高程精度为20厘米。峰值采样率达15~30千赫兹，可生成密度极高的空间高程数据集；单次飞行任务仅需3~4小时即可完成超过100公里海岸线的测绘工作。对该区域生成的高程地图进行分析，可作为土地开发管理决策的有效辅助工具。