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Drainage Basins



Roads:   Identification Information

Originator:  EROS Data Center

                                Date:  unknown

                                Title:  HYDRO 1K Elevation Derivative Database

                                Purpose:  The Hydro1k Drainage Basins are a general purpose global database designed to support

Geographic Information Systems applications. 

Abstract:  The drainage basins distributed with the HYDRO1k data set suite are derived using the vector stream networks along with the flow direction data set. Each polygon in the basin data set has been tagged with a Pfafstetter code uniquely identifying each sub-basin. A detailed description of the coding scheme can be found in Verdin. Additional attributes defining the characteristics of each sub-basin have been developed. These are described in the Readme file. These data are available in an ARC/INFO export format..


                                Access Constraints:  none

                                Use Constraints:  none

            Ordering Instructions:  Datasets are available from the web page below.


                                Contact Address:  47914 252nd Street.

                                City: Sioux Falls

                                State or Province: SD

                                Postal Code: 57198-0001

                                Country: USA


Online Linkage:  http://edcdaac.usgs.gov/gtopo30/hydro/


                                Entity and Attribute Information (table heading explanations)

Shape:  ArcView file type

Area: Area of polygon (m2)

Perimeter: Perimeter of polygon (m)

Level1 to Level6: Pfafstetter units of each polygon

Slope_mean: Mean value of the slopes within the subbasin (degree)

Slope_stdev: Standard deviation of the slopes within the subbasin (degree)

Aspect_mean: Mean value of the aspects within the subbasin (degree from N)

Aspect_stdev: Standard deviation of the aspects within the subbasin (degree from N)

Dem_mean: Mean elevation value within the subbasin (m)

Dem_stdev: Standard deviation of the elevations within the subbasin (m)

Cti_mean: unknown

Cti_stdev: unknown


Global GIS Note: To help with space the polygons were generalized to reduce file size.  The polygons were generalized with a factor of 0.007 degrees, which would allow shifts less than one kilometer at the equator. But in general there was not a noticeable difference.