Many developing countries have witnessed the urgent need of accelerating cadastral surveying processes. Previous studies found that large portions of cadastral boundaries coincide with visible physical objects, namely roads, fences, and building walls. This research explores the application of airborne laser scanning (ALS) techniques on cadastral surveys. A semi-automated work?owisdevelopedtoextractcadastralboundariesfromanALSpointclouds. Firstly,atwo-phased work?ow was developed that focused on extracting digital representations of physical objects. In the automated extraction phase, after classifying points into semantic components, the outline of planar objects such as building roofs and road surfaces were generated by an α-shape algorithm, whilst the centerlines delineatiation approach was ?tted into the lineate object—a fence. Afterwards, the extracted vector lines were edited and re?ned during the post-re?nement phase. Secondly, we quantitatively evaluated the work?ow performance by comparing results against an exiting cadastral map as reference. It was found that the work?ow achieved promising results: around 80% completeness and 60% correctness on average, although the spatial accuracy is still modest. It is argued that the semi-automated extraction work?ow could effectively speed up cadastral surveying, with both human resources and equipment costs being reduced.
展开▼
