Footprint-Based 3D Generalization of Building Groups for Virtual City Visualization
This paper proposes a footprint-based generalization approach for 3D building groups in the context of city visualization. The goal is to reduce both geometric complexity and information density, meanwhile maintaining a rather recognizable shape. The emphasis is placed on converting 3D generalization tasks into 2D issues via buildings' footprints. In order to find suitable units for footprint projection and generalization, which should hold both semantic meaning and simple geometry, a
... ometry, a meaningful partition is firstly introduced (from CityGML building models). For roof generalization, a new perspective is presented: to divide a building model into Top + Body, so that the Top part could be transplanted onto the extruded model by displacement. Two algorithms are developed for two types of building groups: one with a minor height difference and the other with a major height difference. For the former one, the outer units are detected and aggregated to represent the whole group. For the latter one, an iteration of aggregation is performed on subgroups. Each time the highest unit and its neighbors compose the subgroup. The algorithms are tested on two building groups and one part of a 3D city model.