Lot division is the process used to extract valid polygonal boundaries for building construction from the enclosed regions of the primary and secondary road networks. The algorithm operates on both convex and concave shaped areas and also supports filament roads as illustrated in the suburban example below.
The lot division algorithm works by subdividing each region using a deviated perpendicular bisector of the longest side. Two or more polygons can result from the operation and subdivision is continued recursively until a target lot size is reached. Lots that do not have direct road access are excluded from the final set.
Problems were encountered with the realism of the resulting output. The algorithm worked fine for regular square like blocks but when applied to suburban or irregular shapes the resulting lots appeared angular and misaligned. To improve the realism of the output the shape and position of the lots had to be improved. I found that by prioritising subdivision along the road access sides the shapes of the lots became more regular and almost all lots are positioned perpendicular to their access road.
