A national map of riverine median bed-material particle size over CONUS

This is a vector-format map (polyline shapefiles) of the median bed-material sediment particle size (D50) over the contiguous United States. This map is derived by combining the USGS sediment observations, the channel and watershed characteristics from two existing datasets (medium-resolution NHDplus and ScienceBase), and state-of-the-art machine learning techniques.本数据集为美国本土48州范围内的河床沉积物中位粒径（D50）矢量格式地图（折线型形状文件（polyline shapefiles））。该地图通过融合美国地质调查局（USGS）的沉积物观测数据、两份现有数据集（中等分辨率NHDplus与ScienceBase）提取的河道与流域特征，结合当前最先进的机器学习技术构建而成。