EAARL-B Topography-Big Thicket National Preserve: Menard Creek Corridor Unit, Texas, 2014

A first-surface topography Digital Surface Model (DSM) mosaic for the Menard Corridor Unit of Big Thicket National Preserve in Texas was produced from remotely sensed, geographically referenced elevation measurements collected on January 21 and 22, 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.

本数据集为美国德克萨斯州大密林国家保护区（Big Thicket National Preserve）梅纳德走廊单元的首表面地形数字地表模型（Digital Surface Model, DSM）镶嵌图，由美国地质调查局（U.S. Geological Survey）联合国家公园管理局墨西哥湾沿岸网络分部，基于2014年1月21日至22日采集的遥感地理参考高程测量数据制作而成。该区域的高程测量采用第二代实验先进机载研究激光雷达（Experimental Advanced Airborne Research Lidar, EAARL-B）完成，这是一种搭载于航空器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口将高频激光束投射至地球表面，并记录激光束发射时刻与机载平台接收反射激光信号时刻之间的时间差。飞机以约55米每秒的飞行速度、300米左右的作业高度飞越目标区域，形成宽度约240米的激光扫描带，平均点密度达1.4个点/平方米。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过100公里海岸线的测绘工作。对某一区域生成的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工具。