Analysis of the Usefulness of LiDAR DEM to Update the River Network in the Topographic Database

Detection of river network based on DEM analysis is fairly well described in the literature. However the aspect of the quality of input data is often overlooked. The publication presents a solution involving the use of high resolution DTM in order to verify the effectiveness of the flow direction algorithm. In the first step, based on the data ALS, rasters in the form of a regular grid of different cell size (1 m, 2 m and 5 m) was generated. After that, based on 2 m and 5 m rasters, grids with a resolution of 1 m were created. The raster analysis was carried out using an D8 algorithm. The study was conducted for the area of the hilly nature. The result was several variants of the river network and compared with the reference network derived from BDOT10k. The obtained results allowed to determine the appropriate resolution of DTM and the optimal value accumulation factor, which determines the density of the river network.