New D16 Algorithm for Surface Water Flow Direction

D8 algorithm is a widely used on raster-based dataset to illustrate the correlation and relationship of any particular pixel with its neighbouring pixels in water flow direction model. Unfortunately, several limitations of D8 algorithm are detected: flow divergence in ridge area cannot be modelled, not suitable for sub-catchment identification and others. While, there is a high demands to provide accurate flow direction information is encouraged by the several applications on drainage network planning, agricultural sector and some related construction planning. Thus, the aim of the study is to develop a new algorithm that will improve the efficiency, accuracy, and reliability of current D8 algorithm on surface Single Flow Direction (SFD) modelling. D16 algorithm is not only introduced by adding eight new additional flow direction options, but also provide some additional rules and equations to overcome the weaknesses of D8. This study involved the process of deriving D16 model, logical structures and constructing the best equations into a small executable program. Lastly, the comparison results between D8 and D16 algorithm on local topographic map, Shuttle Radar Topography Mission (SRTM), Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and Light Detection and Ranging (LiDAR) data is discussed in details to evaluate the accuracy of D16 algorithm.