Topographic Lidar Survey of the Chandeleur Islands, Louisiana, February 6, 2012 -- Bare Earth DEMs

A topographic Lidar survey was conducted on February 6, 2012, over the Chandeleur Islands, Louisiana. The data were collected at a nominal pulse space of 0.5-meter (m) and processed to identify bare earth elevations. Bare earth digital elevation models (DEMs) were generated based on these data. Digital Aerial Solutions, LLC, was contracted by the U.S. Geological Survey (USGS) to collect and process the lidar data. The bare earth DEMs are 32-bit floating point ERDAS Imagine (IMG) files with a horizontal spatial resolution of 1-m by 1-m. They are in decimal degree geographic coordinates, North American Datum 1983, National Spatial Reference System 2007 (NAD83 NSRS2007)). Their vertical datum is North American Vertical Datum 1988, Geoid 2009, Geodetic Reference System 1980 (NAVD88 GEOID09 GRS80) in meters. Thirty-three DEMs, based on a 2-kilometer (km) by 2-km tiling scheme, cover the entire survey area. These lidar data are available to Federal, State and local governments, emergency-response officials, resource managers, and the general public.2012年2月6日，针对美国路易斯安那州尚德莱尔群岛（Chandeleur Islands）开展了地形激光雷达（Lidar）测量作业。本次数据以0.5米的标称脉冲间距采集，并经处理以识别裸地高程；基于该数据生成了裸地数字高程模型（Digital Elevation Models, DEMs）。美国地质调查局（U.S. Geological Survey, USGS）委托Digital Aerial Solutions, LLC公司负责该激光雷达数据的采集与处理工作。 该裸地DEM数据为32位浮点型ERDAS Imagine（IMG）格式文件，水平空间分辨率为1米×1米，采用十进制度地理坐标系，基准为1983年北美大地基准、2007年国家空间参考系统（North American Datum 1983, National Spatial Reference System 2007, NAD83 NSRS2007）；其垂直基准为1988年北美垂直基准、2009年大地水准面、1980年大地参考系统（North American Vertical Datum 1988, Geoid 2009, Geodetic Reference System 1980, NAVD88 GEOID09 GRS80），高程单位为米。本次测区采用2千米×2千米的分幅方案，共包含33幅DEM，完整覆盖全部测量区域。 此类激光雷达数据可向联邦、州及地方政府、应急响应人员、资源管理者以及普通公众开放获取。