USGS Legacy Benchmark Descriptions

The benchmark descriptions are grouped by United States Geological Survey (USGS) 15-minute quadrangles. Datums: North American Datum of 1927, National Geodetic Vertical Datum of 1929, Sea Level Datum of 1929. The documents were scanned to preserve the historic horizontal and vertical survey control data from USGS. Datasheets: https://kygeonet.ky.gov/ngs/usgs_datasheets/本基准描述按美国地质调查局（United States Geological Survey, USGS）15分幅图进行分组。采用的大地基准包括：1927年北美大地基准面（North American Datum of 1927）、1929年国家大地垂直基准面（National Geodetic Vertical Datum of 1929）以及1929年海平面基准面（Sea Level Datum of 1929）。本数据集通过扫描文档以留存美国地质调查局的历史性水平与垂直测量控制数据。数据表链接：https://kygeonet.ky.gov/ngs/usgs_datasheets/