Integrated Topography and Bathymetry for the Eastern Shore of Virginia

VERSION 2.0 DEM Description This dataset integrates elevation and bathymetry data from multiple sources into a single mostly-seamless digital elevation model (DEM) that covers the entire Eastern Shore of Virginia and its surrounding coastal waters. Data sources include airborn LiDAR, VCRLTER and ODU bathymetric surveys, NOAA navigational data, NOS oceanographic surveys, USGS NED data plus contours and features from topo quad maps, and VGIN-VBMP aerial imagery. Proposed uses for the dataset include deriving detailed watershed boundaries, hypsometric curves, tidal prisms, 3-D physical models, and input for numerical hydrodynamic simulation models. The version 2.0 DEM (August 2014) is suitable for both local- and regional-scale analyses. It has a resolution matched to the LiDAR data (3.048 m. or 10 ft.), resulting in 31,152 x 46,002 cells (5.4 Gigabyte in ESRI GRID format). Users can aggregate to coarser cell resolutions as needed. The data is projected in UTM Zone 18 North coordinates relative to the WGS84 horizontal datum. All elevations are in meters relative to the NAVD88 vertical datum. Spatially modelled conversion factors between NAVD88 and local sea level datums (MSL, MLW, MHW, etc.) based on NOAA VDATUM data are available as a separate dataset (VCR13215). See "METHODS" for full details on data sources and integration methodologies.

版本2.0数字高程模型（Digital Elevation Model，DEM）说明
本数据集整合多源高程与水深数据，构建得到近乎无缝的数字高程模型，覆盖范围涵盖弗吉尼亚东海岸及其周边近海水域。数据来源包括：机载激光雷达（Light Detection and Ranging，LiDAR）、VCRLTER与ODU水深测量数据、美国国家海洋和大气管理局（National Oceanic and Atmospheric Administration，NOAA）航海数据、NOS海洋调查数据、美国地质调查局国家高程数据集（USGS NED），以及地形图图幅的等高线与要素信息、VGIN-VBMP航空影像。
本数据集的拟用场景包括：提取详细流域边界、高程面积曲线、潮汐棱柱体、三维物理模型，以及作为数值水动力模拟模型的输入数据。
本版本2.0的DEM发布于2014年8月，适用于局地与区域尺度的分析。其分辨率与机载激光雷达数据一致（3.048米，即10英尺），栅格单元总数为31152×46002，以ESRI GRID格式存储时容量为5.4吉字节。用户可根据需求将栅格聚合至更粗的分辨率。
该数据集采用世界大地测量系统1984（World Geodetic System 1984，WGS84）水平基准下的通用横轴墨卡托（Universal Transverse Mercator，UTM）投影带18北坐标系，所有高程值以北美垂直基准面1988（North American Vertical Datum 1988，NAVD88）为基准，单位为米。基于NOAA VDATUM数据构建的NAVD88与当地海平面基准面（平均海平面Mean Sea Level，MSL、平均低潮Mean Low Water，MLW、平均高潮Mean High Water，MHW等）的空间转换系数，可作为独立数据集（VCR13215）获取。
详细的数据来源与整合方法请参见"METHODS"章节。