High resolution LiDAR Data for Hog Island, VA, 2011

High Resolution LiDAR elevation and nearshore bathymetry data for Hog Island, Northampton County, VA, collected on October 11, 2011 on behalf of the USACE Engineer Research and Development Center using the Coastal Zone Mapping and Imaging Lidar (CZMIL) system. CZMIL integrates a lidar sensor with topographic and bathymetric capabilities, a digital camera and a hyperspectral imager on a single remote sensing platform for use in coastal mapping and charting activities. RGB air photo imagery is provided as a separate VCRLTER dataset. Two data entities are included here: (1) the LiDAR point cloud (approximate point density of 100 points per square meter [denser over structures and dense vegetation], average point spacing of 0.48 m.) contained in a mosaic of 211 LAS files (standard LiDAR LAS file format); and (2) a polygon INDEX shapefile showing the footprint of each LAS file and containing a summary description of each LAS file in the attribute table (LAS file name, point count, point spacing, and minimum and maximum elevation). Note that the two co-collected 2011 USACE datasets (LiDAR and RGB ) are in different coordinate systems: (A) the horizontal and vertical units of the LiDAR data are in US feet, not meters. (B) the horizontal units of the associated RGB mosaic images are in [standard] meters. Also Note that THESE ARE VERY LARGE DATASETS and download should not be attempted unless you have a fast network connection and plenty of disk space. The LAS file data collection is 7.3 GB compressed (11.7 GB uncompressed). The RGB imagery mosaic data collection is 12.9 GB compressed (30.8 GB uncompressed).

本数据集为弗吉尼亚州北安普顿县霍格岛的高分辨率激光雷达（LiDAR）高程数据与近岸水深数据，采集于2011年10月11日，由美国陆军工程兵团（USACE）工程研究与发展中心委托，采用海岸带测绘与成像激光雷达（Coastal Zone Mapping and Imaging Lidar, CZMIL）系统完成。CZMIL将激光雷达传感器与地形、水深测绘功能集成，搭载数码相机与高光谱成像仪于单一遥感平台，用于海岸带制图与海图绘制工作。RGB航空影像数据集以独立的VCRLTER数据集形式提供。本次发布包含两类数据实体：(1) 激光雷达点云数据：点密度约为100点/平方米（建筑与茂密植被区域点云更密集），平均点间距为0.48米，存储于211个LAS文件（标准LiDAR LAS文件格式）的镶嵌集合中；(2) 多边形索引形状文件：用于展示每个LAS文件的覆盖范围，并在属性表中包含各LAS文件的摘要信息，包括LAS文件名、点数量、点间距以及高程的最小值与最大值。需注意，本次同步采集的2011年USACE两类数据集（激光雷达与RGB影像）采用了不同的坐标系：(A) 激光雷达数据的水平与垂直单位均为美制英尺，而非米；(B) 配套的RGB镶嵌影像的水平单位为[标准]米。此外请注意，本数据集体量极大，若无高速网络连接与充足磁盘空间，请勿尝试下载。其中LAS文件数据压缩后大小为7.3 GB（解压后为11.7 GB），RGB影像镶嵌数据压缩后大小为12.9 GB（解压后为30.8 GB）。