50' Contour Lines - La Paz County

This dataset represents 50 foot contour intervals for La Paz 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拉巴斯县（La Paz County）的50英尺等高距地形数据。数据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）的晕渲TIFF（TIF）文件生成，经处理后得到适配各县级行政区或其部分区域的ESRI格式覆盖数据。 美国地质调查局已构建国家高程数据集（NED），该数据集是最优可用高程数据的无缝镶嵌成果，其核心初始源数据为美国本土的7.5分高程数据。除完备的7.5分高程数据外，研发团队还开发了高效处理流程，用于滤除现有数据中的生产伪影、转换至北美83坐标系（NAD83）、进行边缘匹配，并填补图幅接缝处的缺失狭条数据。 国家高程数据集的处理流程带来的一大优势，是为坡度与水文衍生参数的计算提供了更为优质的高程数据基础。 NED的1角秒与1/3角秒数据规格如下：采用地理坐标系，水平基准面为北美83坐标系（NAD83，阿拉斯加州除外，其水平基准面为北美27坐标系（NAD27））；垂直基准面为NAVD88（阿拉斯加州除外，其垂直基准面为NAVD29）；Z轴单位为米。