50' Contour Lines - Mohave County

This dataset represents 50 foot contour intervals for Mohave County, Arizona. The data were created by processing hillshade TIF files derived from the U.S. Geological Survey National Elevation Dataset. The processing produced ESRI formatted coverages for each county or part of a county. The U.S. Geological Survey has developed a National Elevation Dataset (NED). The NED is a seamless mosaic of best-available elevation data. The 7.5-minute elevation data for the conterminous United States are the primary initial source data. In addition to the availability of complete 7.5-minute data, efficient processing methods were developed to filter production artifacts in the existing data, convert to the NAD83 datum, edge-match, and fill slivers of missing data at quadrangle seams. One of the effects of the NED processing steps is a much-improved base of elevation data for calculating slope and hydrologic derivatives. The specifications for the NED 1 arc second and 1/3 arc second data are - Geographic coordinate system, Horizontal datum of NAD83, except for AK which is NAD27, Vertical datum of NAVD88, except for AK which is NAVD29, Z units of meters.本数据集涵盖亚利桑那州莫哈维县（Mohave County）的50英尺等高距数据。其通过处理源自美国地质调查局（U.S. Geological Survey）国家高程数据集（National Elevation Dataset, NED）的山体阴影TIF文件生成。该处理流程为每个县域或部分县域生成了ESRI格式的Coverage数据。 美国地质调查局已研发出国家高程数据集（National Elevation Dataset, NED），该数据集是最优可用高程数据的无缝镶嵌成果，美国本土的7.5弧分高程数据为其主要初始源数据。除完整覆盖7.5弧分数据外，研发人员还开发了高效处理方法，用于过滤现有数据中的生产伪影、转换至NAD83基准面、执行边缘匹配，并填补图幅接缝处缺失的细碎数据空白。国家高程数据集的处理流程带来的一项核心优势，是为坡度与水文衍生参数的计算提供了大幅优化的高程数据基础。 NED 1弧秒与1/3弧秒数据的技术规范如下：采用地理坐标系，水平基准面为NAD83（阿拉斯加州AK除外，其水平基准面为NAD27）；垂直基准面为NAVD88（阿拉斯加州AK除外，其垂直基准面为NAVD29）；Z轴单位为米。