USGS 1/3 arc-second Digital Elevation Model

<p>This collection of the <a href='https://www.sciencebase.gov/catalog/item/4f70aa9fe4b058caae3f8de5'>3D Elevation Program (3DEP)</a> is at 1/3 arc-second (approximately 10 m) resolution. The 3DEP data holdings serve as the elevation layer of The National Map, and provide foundational elevation information for earth science studies and mapping applications in the United States. Scientists and resource managers use 3DEP data for hydrologic modeling, resource monitoring, mapping and visualization, and many other applications. The elevations in this DEM represent the topographic bare-earth surface. The seamless 1/3 arc-second DEM layers are derived from diverse source data that are processed to a common coordinate system and unit of vertical measure. These data are distributed in geographic coordinates in units of decimal degrees, and in conformance with the North American Datum of 1983 (NAD 83). All elevation values are in meters and, over the continental United States, are referenced to the North American Vertical Datum of 1988 (NAVD88). The vertical reference will vary in other areas. The seamless 1/3 arc-second DEM layer provides coverage of the conterminous United States, Hawaii, Puerto Rico, other territorial islands, and in limited areas of Alaska. These seamless DEMs were referred to as the National Elevation Dataset (NED) from about 2000 through 2015 at which time they became the seamless DEM layers under the 3DEP program and the NED name and system were retired. All 3DEP products are public domain.</p> <a href='https://www.sciencebase.gov/catalog/item/4f70aa9fe4b058caae3f8de5'>Click here</a> for more details on this dataset

本数据集隶属于3D高程计划（3D Elevation Program, 3DEP），其详情可访问链接<https://www.sciencebase.gov/catalog/item/4f70aa9fe4b058caae3f8de5>。该数据集空间分辨率为1/3弧秒（约10米）。3DEP数据资产作为美国国家地图（The National Map）的高程图层，为美国境内的地球科学研究与制图应用提供基础高程信息。科学家与资源管理者可将3DEP数据应用于水文建模、资源监测、制图与可视化等诸多场景。本数据集所包含的数字高程模型（Digital Elevation Model, DEM）中的高程值，代表地表裸土地形表面。无缝1/3弧秒DEM图层源自多源异构数据，经统一处理至通用坐标系与垂直测量单位。此类数据以十进制度为单位的地理坐标进行分发，符合1983年北美大地基准面（North American Datum of 1983, NAD 83）标准。所有高程值单位均为米，在美国本土大陆范围内以1988年北美垂直基准面（North American Vertical Datum of 1988, NAVD88）为参考基准，其他区域的垂直参考基准可能存在差异。无缝1/3弧秒DEM图层的覆盖范围包括美国本土48州、夏威夷、波多黎各及其他海外领土岛屿，仅在阿拉斯加部分区域有数据覆盖。这类无缝DEM在2000年至2015年间被称为国家高程数据集（National Elevation Dataset, NED），2015年之后归入3DEP计划下的无缝DEM图层，原NED名称与系统随之停用。所有3DEP产品均属于公共领域。

点击<https://www.sciencebase.gov/catalog/item/4f70aa9fe4b058caae3f8de5>即可查看该数据集的更多详情。