U.S. General Soil Map (STATSGO2)

This data set consists of general soil association units. It was developed by the National Cooperative Soil Survey and supersedes the State Soil Geographic (STATSGO) data set published in 2006. It consists of a broad based inventory of soils and nonsoil areas that occur in a repeatable pattern on the landscape and that can be cartographically shown at the scale mapped. The data set was created by generalizing more detailed soil survey maps. Where more detailed soil survey maps were not available, data on geology, topography, vegetation, and climate were assembled, together with Land Remote Sensing Satellite (LANDSAT) images. Soils of like areas were studied, and the probable classification and extent of the soils were determined. Map unit composition was determined by transecting or sampling areas on the more detailed maps and expanding the data statistically to characterize the whole map unit. This data set consists of georeferenced vector digital data and tabular digital data. The map data were collected in 1-by 2-degree topographic quadrangle units and merged into a seamless national data set. It is distributed in state/territory and national extents. The soil map units are linked to attributes in the National Soil Information System data base which gives the proportionate extent of the component soils and their properties. Individual Metadata [XML]本数据集由通用土壤组合单元构成，由国家合作土壤调查（National Cooperative Soil Survey）研发，并替代了2006年发布的州土壤地理（STATSGO）数据集。其涵盖了在地表以可重复模式出现、且可按成图比例尺进行制图表达的全域土壤与非土壤区域的广泛清单。本数据集通过概化更详细的土壤调查图件制作而成：在无更详细土壤调查图件的区域，研究人员会整合地质、地形、植被与气候数据，并结合陆地遥感卫星（LANDSAT）影像开展相关工作，对相似区域的土壤进行研究，确定土壤的推定分类与分布范围；通过在更详细的图件上对区域进行样带布设或采样，并通过统计学方法扩展数据以刻画整个图斑单元的特征，进而确定图斑单元的组成。本数据集包含地理参考矢量数字数据与表格型数字数据，图件数据以1°×2°地形四边形图幅为单元采集，最终合并为无缝衔接的全国数据集。该数据集可按州/领地及全国范围进行分发。土壤图斑单元与国家土壤信息系统（National Soil Information System）数据库中的属性相关联，这些属性可提供组成土壤的占比范围及其理化性质。本数据集附带独立元数据[XML]。