1. Global Hydrologic Data Development
presented by
Kwabena Asante
acknowledgements
Dr David R. Maidment
Dr Francisco Olivera
Dr Jay Famiglietti
Center for Research in Water Resources
The University of Texas at Austin

2. GIS Hydro ‘99: Digital Atlas
Digital Atlas of the World Water Balance
The Digital Atlas contains
24 grids
6 coverages
of processed terrain data
for continental scale hydrologic modeling including

3. Data Structure

4. Preprocessing Data 30” DEMs from EROS Data Center, USGS Lower datum
Mean
Sea
Level
New
Reference
Datum
Lower
datum
1 km
Project

5. Basic Map Projections

6. Projection Parameters
Lambert Azimuthal Equal Area Projection
Cell size: 1000 m
Projection Centers as defined by the USGS:
Continent
Longitude
Latitude
Africa
20o 0’ 0”
5o 0’ 0”
Asia
100o 0’ 0”
45o 0’ 0”
Australia
135o 0’ 0”
-15o 0’ 0”
Europe
55o 0’ 0”
North America
-100o 0’ 0”
South America
-60o 0’ 0”

7. Projected View North America Europe Asia South America Africa
Australia

8. Europe - Asia Divide Considerations: Drainage Basins No. of Grid Cells
Europe = 28 million
Asia = 48 million
Caspian Sea
Drainage Basin
Area = 5.4 million km2

9. Pits and Inland Catchments
Assign
NODATA Cells
Inland
Catchments
Other
Pits
Fill
Identify inland catchments and fill all other pits

10. 27 Major Inland Catchments

11. Processed Terrain Grid

12. Flow Direction Grids 1 2 4 8 16 32 64
128

13. Flow Length Grids

14. Flow Accumulation Grids

15. Defining Basin Outlets: 3o Ocean Boxes

16. 1500 Major Drainage Basins

17. USGS Hydro1k Delineation
Watersheds from
USGS delineation
Drainage Basins from this delineation

18. GIS Hydro ‘99: Digital Atlas
Digital Atlas of the World Water Balance
Processed terrain data
Major Drainage Basins
Processed Terrain Grids
Flow Direction Grids
Flow Length Grids
Flow Accumulation Grids
Documentation of the data development
Links to previous versions of the atlas containing global hydrologic data including
Precipitation
Temperature
Radiation
Soil Water Holding Capacity

19. Conclusions
Derived hydrologic modeling parameters from the finest terrain data available
Delineated Drainage Basins
for sections of coastal-line
using these data

20. I’m done