Abstract: Channel is the basic parameter of hydrologic information, the accurate extraction of channel information provides a prerequisite for the construction of hydrologic model and the classification of the river basin. At present, river network recognition method has often been used to extract channel information. However, the selection of threshold value must be changed for the different river basins. This paper takes the different watersheds in hilly regions of loess plateau as an example, selects DEM with different resolutions respectively, uses different threshold values to extract channel information, researches the effect of DEM resolution to channel information extraction, and finally verifies the threshold range based on the actually gully density. As the result, a reasonable threshold range is suggested, which is suitable for the channel information extraction in hilly regions of loess plateau. The result also indicates that the channel information extracted from different watersheds in the research area have certain similarity in their gully density.

Key words: channel , threshold value , DEM resolution , loess plateau