EAARL-B Topography—Big Thicket National Preserve: Canyonlands and Upper Neches River Corridor Units, Texas, 2014

A first-surface topography Digital Surface Model (DSM) mosaic for the Canyonlands and Upper Neches River Corridor Units of Big Thicket National Preserve in Texas was produced from remotely sensed, geographically referenced elevation measurements collected on January 11, 15, 17, 18, 21, 23, 25, and 29, 2014 by the U.S. Geological Survey, in cooperation with the National Park Service - Gulf Coast Network. Elevation measurements were collected over the area using the second-generation Experimental Advanced Airborne Research Lidar (EAARL-B), 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 density of 1.4 points per square meter. 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.

本数据集为美国得克萨斯州大密林国家保护区（Big Thicket National Preserve）峡谷地与上内皮奇河走廊单元的第一表面地形数字表面模型（Digital Surface Model, DSM）镶嵌图，其数据源自2014年1月11、15、17、18、21、23、25及29日，由美国地质调查局（U.S. Geological Survey）联合国家公园服务局墨西哥湾沿岸网络（National Park Service - Gulf Coast Network）采集的遥感地理参考高程测量数据。该区域的高程数据采集采用第二代实验先进机载研究激光雷达（Experimental Advanced Airborne Research Lidar, EAARL-B）——一款搭载于航空器的脉冲激光测距系统，可同步测量地面高程、植被冠层与海岸地形。该系统通过航空器机身底部的开口向地球表面发射高频激光束，并记录激光束发射与机载平台接收反射激光信号之间的时间差。航空器以约55米/秒的速度飞越目标区域，飞行高度约300米，形成的激光扫描幅宽约240米，平均点密度达每平方米1.4个点。该系统峰值采样率为15-30千赫，可生成密度极高的空间高程数据集；单次3至4小时的飞行任务即可轻松完成超100公里海岸线的测绘工作。对某一区域的生成高程地图进行分析后，可作为土地开发相关管理决策的实用辅助工具。