A FORTRAN subroutine for cartographic generalization
Computers & Geosciences
An outlet breaching algorithm for the treatment of closed depressions in a raster DEM
Computers & Geosciences
A methodology for aligning raster flow direction data with photogrammetrically mapped hydrology
Computers & Geosciences
Error propagation of DEM-based surface derivatives
Computers & Geosciences
An efficient depression processing algorithm for hydrologic analysis
Computers & Geosciences
An efficient depression processing algorithm for hydrologic analysis
Computers & Geosciences
The effect of error in gridded digital elevation models on the estimation of topographic parameters
Environmental Modelling & Software
Optimum design of chamfer distance transforms
IEEE Transactions on Image Processing
A new algorithm for grid-based hydrologic analysis by incorporating stormwater infrastructure
Computers & Geosciences
Extension of a GIS procedure for calculating the RUSLE equation LS factor
Computers & Geosciences
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Length of river reaches is one of the most important characteristics of stream networks when applying hydrological or environmental simulation models. A common method of obtaining estimates of river lengths is based on deriving flow directions, accumulated area and drainage lines from raster digital elevation models (DEM). This method leads to length estimates with variable accuracy, which depends on DEM horizontal resolution, flatness of terrain, DEM vertical accuracy, the algorithm used to obtain flow directions and the way by which distances are calculated over raster structures. We applied an automatic river length extraction method for eight river reaches in the River Uruguay Basin (206000km^2), in Southern Brazil, and compared its results to the lengths obtained from drainage vector lines digitalized over satellite images. Our results show that relative errors can be higher than 30% in flat regions with relatively low DEM resolution. Preprocessing of DEM by the method known as stream burning greatly improves results, reducing errors to the range 1.9-7.4%. Further improved estimates were obtained by applying optimized values for the length of orthogonal and diagonal steps called distance transforms, reducing the errors to the range -2.0-3.3%.