Highly accurate global polygonal drainage basin data (PDBD) was developed in this research. The PDBD was derived from digital elevation models (DEMs) at high-resolution (about 100 m-1 km) by automatic and non-automatic methods to suppress DEM errors which derive wrong PDBD. The automatic methods are 'stream burning' and 'ridge fencing', while the non-automatic method is one which manually corrects DEM errors ('manual correction'). For the derivation of the PDBD, we collected and used geographic basin and river data published from governments, institutes, publishers, and water-related programs. The PDBD derived from the DEMs at high-resolution can represent the boundaries of the basins in detail, and precise geographic and topographic information can be thus derived. These features are helpful for regional and global analysis, assessment, and management with hydrological models in water-related studies. To assess the accuracy of the derived PDBD, we conducted two types of comparisons. Firstly, we geographically compared the derived PDBD with the collected basin data. The derived PDBD showed good geographic agreement with the collected basin data, and the geographic agreement of the derived PDBD was better than that of HYDRO1k. Secondly, we compared upstream areas and discharges based on the derived PDBD with the observed upstream areas and discharges. The upstream areas and discharges based on the derived PDBD showed good agreement with the observed upstream areas and discharges, and the agreement of the derived PDBD was better than that of HYDRO1k. These comparisons reveal that the derived PDBD are highly accurate and reliable. The derived PDBD are thus thought to offer the best information on the surface drainage of the earth. Copyright (C) 2008 John Wiley & Sons, Ltd.
