This study assesses the mapping of standard railway and drainage design scales using freely available resources to achieve the necessary accuracy for hydrological simulations of railway infrastructure in Chiang Mai, Thailand. Two distinct sites were selected: a flat, small-scale urban terrain and a remote, expansive mountainous area on the north-eastern outskirts of Chiang Mai. The analysis employed a Digital Elevation Model (DEM) with a resolution of 12.5 meters per pixel to calculate flow direction, route waterways, and delineate catchments. The discussion section examines the results in relation to the initial study conditions and highlights the challenges in directing flow within the urban study area. The conclusions suggest integrating metadata into DEM applications as part of ongoing research efforts.