The spatial data were obtained from the Natural Resources Conservation Service and are current as of February 2013. The soil data were downloaded in two file forms, a .txt file with the tabular attribute information and a shapefile with the geometric information. The .txt file was processed in Microsoft Excel and joined with the shapefile in ArcMap to populate the geometric information with associated attributes. The attributes were modified to include area symbol, spatialver, map unit symbol, map unit key, and soil description. 'This data set consists of general soil association units. It was develped by the National Cooperative Soil Survey and supersedes the State Soil Geographic (STATSGO) data set published in 1994. 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.' - NRCS Source.

Яндекс.Метрика Рейтинг Free Web Counter
page counter
Last Modified: April 18, 2016 @ 7:09 am