Occlusion-free visualization of important geographic features in 3D urban environments

Abstract

Modern cities are dense with very tall buildings, which often leads to features of interest (FOIs, e.g., relevant roads and associated landmarks) being occluded by clusters of buildings. Thus, from any given point of view, users can see only a small area of the city. However, it is currently an important technical problem to maintain the visibility of FOIs while preserving the urban shapes and spatial relationships between features. In this paper, we present a novel automatic visualization method to generate occlusion-free views for FOIs in real time. Our method integrates with three effective cartographic schemes: Route broadening, building displacement, and building scaling, using an optimization framework A series of distortion energies are presented to preserve the urban resemblance, considering the view position and the urban features based on spatial cognition to maintain spatial and temporal coherence. Our approach can be used to visualize large urban environments at interactive framerates in which the visibility of the occluded FOIs is maximized while the deformation of the landscape's shape is minimized. Using this approach, the visual readability of such 3D urban maps can be much improved.