EAARL-B Topography-Big Thicket National Preserve: Lance Rosier Unit, Texas, 2014

A first-surface topography Digital Elevation Model (DEM) mosaic for the Lance Rosier Unit of Big Thicket National Preserve in Texas, was produced from remotely sensed, geographically referenced elevation measurements collected on January 15, 21, 22, 25, 26, and 30, 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 spacing of 0.5-1.6 meters. 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厚地国家保护区兰斯·罗西尔单元的第一表面地形（first-surface topography）数字高程模型（Digital Elevation Model，DEM）拼接产品。该数据集由美国地质调查局（U.S. Geological Survey）联合国家公园服务局墨西哥湾沿岸网络，基于2014年1月15、21、22、25、26及30日采集的遥感地理参考高程测量数据制作生成。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），该系统为搭载于机载平台的脉冲激光测距装置，可同步测量地面高程、植被冠层与海岸地形。系统通过飞机机身底部的开口向地球表面发射高频激光束，并记录激光束发射时刻与机载平台接收反射激光信号的时间差。作业时机身飞行高度约300米，飞行速度约55米/秒，可形成宽度约240米的激光扫描带，平均点间距为0.5至1.6米。该系统峰值采样率达15至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。对该区域生成的高程图进行分析后，可作为土地开发相关管理决策的实用辅助工具。