Bypass air model of heat pump drying kiln.

This paper compares the extracted hydrological terrain parameters based on DEM using Rivertools and ArcGIS.The results show that it is better to choose Rivertools to extract hydrological parameters,especially for creating a depressionless DEM;however,the method of stream order classification by Rivertools is too single,among which the river's clip only can be done in the same stream order.Comparatively,ArcGIS has more ways to classify stream order,and the river's clip is not limited by stream order;however,ArcGIS software requires user must know the river system of the research area very well,otherwise,big error could be made during the extraction.According to the Pros and Cons of the two kinds of software,user should combine two kinds of software together and make full use of each software's advantages.Meanwhile,this paper compares the differences between extracted hydrological terrain parameters(length of river system,density of river system,elevation and the area of watershed) based on different resolution of DEM(the grid of DEM is 5 m × 5 m,10 m × 10 m,25 m × 25 m,50 m × 50 m and 100 m × 100 m,respectively) under Rivertools and ArcGIS.The results show that the extracted hydrological terrain parameters from Rivertools are more accurate than that from ArcGIS in somerange of DEM resolution,while the effect of DEM resolution on extracted hydrological terrain parameters using ArcGIS is smaller than that using Rivertools.