ISLSCP Initiative II | Related Pages |
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ISLSCP Initiative II Home General Data Overview Hydrology Data Overview |
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ISLSCP Initiative II |
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Hydrology, Soils, & Topography Data
The purpose of this data development effort was to make use of high-resolution global elevation data to produce coarse scale elevation and elevation-based parameters at 1 and 0.5-degree spatial resolution to support a wide variety of global modeling activities through the International Satellite Land Surface Climatology Project (ISLSCP) Initiative II data collection. The intent was also to produce coarse scale elevation data sets with sufficient statistical information (up to fourth moment) to allow a good statistical description of the sub-cell distribution of any particular elevation parameter (i.e. elevation, slope and aspect). The database used in the data aggregation effort was the HYDRO1k dataset with a native spatial resolution of 1 km, the highest resolution database of global coverage of standard elevation-based derivatives (slope, aspect, elevation, compound topographic index, etc.). HYDRO1k, developed at the U.S. Geological Survey's (USGS) EROS Data Center, is a geographic database providing comprehensive and consistent global coverage of topographically derived data sets. Developed from the USGS' recently released 30 arc-second digital elevation model (DEM) of the world (GTOPO30), HYDRO1k provides a standard suite of geo-referenced data sets (at a resolution of 1 km) that will be of value for all users who need to organize, evaluate, or process hydrologic information on a continental scale (see http://lpdaac.usgs.gov/gtopo30/hydro/ [Internet Link])
Data Provider: Kristine L. Verdin
 Data Files (ISLSCP II Disc #1) |
 Data Set Documentation |
 Image Viewing Tutorial |
The files have been compressed using the PKZip program. Each uncompressed file contains space-delimited ASCII text. The half-degree data has 720 values per line and 360 lines of data (0.5 degree resolution). The 1-degree data has 360 values per line and 180 lines of data (1 degree resolution). Each line is terminated by a newline character. The data are structured so that the upperleft corner of the first pixel is located at 90 North latitude and 180 West longitude.
The HYDRO1k data set for ISLSCP2 is made up of 26 data layers for each resolution:
| File Name | Description |
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| aspect_kurt | Kurtosis of the aspects within each cell |
| aspect_mean | Mean aspect of each cell |
| aspect_median | Median aspect of each cell |
| aspect_skew | Skewness in aspect for each cell |
| aspect_stdev | Standard deviation in aspect for each cell |
| cti_kurt | Kurtosis in CTI for each cell |
| cti_max | Maximum CTI within each cell |
| cti_mean | Mean CTI within each cell |
| cti_median | Median CTI within each cell |
| cti_skew | Skewness in CTI for each cell |
| cti_stdev | Standard deviation in CTI for each cell |
| elev_kurt | Kurtosis in elevation values within each cell |
| elev_max | Maximum elevation value within each cell |
| elev_mean | Mean elevation value within each cell |
| elev_median | Median elevation value within each cell |
| elev_min | Minimum elevation value within each cell |
| elev_range | Range of elevation values within each cell |
| elev_skew | Skewness in elevation values within each cell |
| elev_stddev | Standard deviation of the elevation values within each cell |
| landmask | Original land/water mask used in the aggregation of HYDRO1k |
| landmask_dif | Differences between the ISLSCP2 land/water mask and the original land/water mask |
| slope_kurt | Kurtosis of the slopes within each cell |
| slope_mean | Mean slope within each cell |
| slope_median | Median slope within each cell |
| slope_skew | Skewness of the slopes within each cell |
| slope_stddev | Standard deviation of the slopes within each cell |
Related Pages:
ISLSCP Initiative II Home
General Data Overview
Hydrology Data Overview
HYDRO1k Elevation-derived Products
Revision Date: September 28, 2004