Soil General Map STATSGO

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.本数据集包含通用土壤组合单元。其由国家合作土壤调查局（National Cooperative Soil Survey）开发，并取代了2006年发布的州土壤地理（STATSGO）数据集。本数据集涵盖了景观中以可重复格局出现的土壤与非土壤区域的全面普查清单，且可按成图比例尺进行制图展示。该数据集通过概化更详细的土壤调查图件生成；若无法获取详细土壤调查图件，则需汇编地质、地形、植被、气候数据，配合陆地遥感卫星（LANDSAT）影像开展工作。研究人员会对相似区域的土壤展开研究，确定土壤的推定分类与分布范围。图斑单元的组成通过在详细图件上开展样带调查或区域采样，并通过统计外推以表征整个图斑单元的特征来确定。本数据集包含地理参考矢量数字数据与表格数字数据。图件数据以1×2度地形四分幅图为单元采集，并合并为无缝衔接的国家级数据集。该数据集按州/领地及国家级范围进行分发。土壤图斑单元与国家土壤信息系统数据库中的属性字段相关联，这些属性可提供组成土壤的占比分布范围及其理化性质。