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 proper representation of the global river system is essential for modeling horizontal water transfers. Gridded river networks derived from digital elevation models suffer from various errors, which are particularly severe at coarse resolution. The goal in developing the Simulated Topological Network, or STN-30p, was to provide the large-scale hydrological modeling community an accurate representation of the global river system. STN-30p was developed before HYDRO1k become available, therefore its river network topology and all the derived information form the network such as basin delineation, upstream area, distance to oceans, etc. are independent from HYDRO1k (which is part of the present ISLSCP 2 data compilation), however a corrected DEM is also provided as part of the dataset, which applied correction to the aggregated HYDRO1k elevation at 30' resolution to eliminate the inconsistencies between the network and the DEM.
Data Provider: Charles J. Vörösmarty, Balazs Fekete
 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, at either half-degree resolution ("hd", 720 values per line and 360 lines) or 1-degree resolution ("1d", 360 values per line and 180 lines). 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 STN data set for ISLSCP-2 is made up of 8 data layers and two associated attribute tables (for each resolution: hdeg and 1deg):
| File Name | Description |
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| stn_basin_id_hd.asc | Basin grid, which assigns unique identifiers to groups of grid-cells forming individual river basins. |
| stn_basin_attribute_hd.asc (table) | Basin attribute table contains attribute information such as basin name, catchment area, mainstem length, etc. for each individual basin in STN-30p. |
| stn_cell_attribute_hd.asc (table) | Cell attribute table contains attribute information for each land cell in STN30p. |
| stn_flow_accum_hd.asc | Flow accumulation grid or upstream area grid (km^2), which provides the catchment area estimate for each grid cell according to the STN-30p network. |
| stn_flow_direction_hd.asc | Flow direction grid, which represents the horizontal connectivity of the continental land mass. |
| stn_dist2ocean_hd.asc | Distance [km] to the outlet of river basins. |
| stn_mainstem_length_hd.asc | Mainstem length [km] grid. |
| stn_stream_order_hd.asc | Strahler stream order grid. |
| stn_elevation_hd.asc | Adjusted elevation (m) grid, which combines HYDRO1k aggregated elevation at 30-minute resolution with STN-30p, where the inconsistencies between the elevation and the flow direction data sets (i.e. increasing elevation along downstream flow path) were eliminated. |
| stn_slope_hd.asc | Slope (degree) along the STN-30p grid, provides slope information for each grid cell along the cell's flow direction. |
Related Pages:
ISLSCP Initiative II Home
General Data Overview
Hydrology Data Overview
River Routing DEM Data
Revision Date: Septemnber 13, 2004