Roads: Identification Information
Originator: EROS Data Center
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
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)
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.