Geometric quality enhancement of legacy graphical cadastral datasets through thin plate splines transformation

Abstract

In some parts of the world, mainly developing countries, analogue graphical cadastral datasets are still being used, despite the fact that they usually contain large and differential positional distortions. This is because not only do they contain useful information, their replacement would involve lengthy legal procedures, huge financial costs and technical challenges as well. This paper presents a novel approach for the conflation of such legacy graphical cadastral datasets to more reliable and accurate topographical datasets based on the matching of linear features via a non-rigid transformation using thin plate spline transformation. The approach consists of three key steps: extraction of road network which is potentially contained in the graphical cadastral maps; matching of corresponding point and linear features between the extracted road network and a more reliable road network dataset; and computation of the non-rigid transformation between the datasets. Applying this reliable and accurate transformation quantification to the original legacy graphical cadastral dataset showed significant improvement in its geometric quality and positional accuracy.