Abstract
This study developed a new automated construction method of polygonal blocks using road boundary lines with gaps. Polygonal block data are often used in studies of numerical simulation models for rainfall–runoff and flood inundation analysis. In the developed method, connected boundary lines of a street are first merged into boundary polylines. Secondly, directions of boundary polylines are aligned in a clockwise rotation. Next, gaps of boundary polylines are complemented recursively with straight lines. Finally, the areas enclosed by boundary polylines and complemented lines are output as polygonal blocks. This method was applied for the Kanda catchment. Then the shapes of polygonal blocks were validated. Results show that polygonal blocks can be created using the method outlined herein with few failures.
