3D Generalization Lenses for Interactive Focus + Context Visualization of Virtual City Models

Abstract

Focus + context visualization facilitates the exploration of complex information spaces. This paper proposes 3D generalization lenses, a new visualization technique for virtual 3D city models that combines different levels of structural abstraction. In an automatic preprocessing step, we derive a generalized representation of a given city model. At runtime, this representation is combined with a full-detail representation within a single view based on one or more 3D lenses of arbitrary shape. Focus areas within lens volumes are shown in full detail while excluding less important details of the surrounding area. Our technique supports simultaneous use of multiple lenses associated with different abstraction levels, can handle overlapping and nested lenses, and provides interactive lens modification.

Dynamic Mapping of Raster-Data for 3D Geovirtual Environments

“…The advantages of projecting symbols onto the city model geometry are the emphasis of the symbol-object relationship, the reduction of interpretation ambiguities, and the removal of label-scene occlusions. This delivers good visual results for generalized versions of virtual 3D city models [14], viewed from a bird's-eye or a plan perspective. Due to our dynamic concept, the icons can be exchanged, scaled, rotated, or faded view-dependently to ensure an optimal readability of such a 3D digital map.…”

“…The DTCG enables the interactive movement of a lens, while the implicit hierarchy supports the usage of overlapping lenses. Our approach can further be used to combine different city model geometries (Figure 3.D) as a simplified version of the approach presented in [14]. Using multiple rendering passes, this can be achieved by projecting binary masks and enable alpha testing to discard the respective fragments.…”

Conformal Magnifier: A Focus+Context Technique with Local Shape Preservation

“…For the virtual city, Qu et al [30] have described an FþC route zoom and information overlay method for 3D urban environments. Trapp et al [42] have proposed a 3D generalization lens for the interactive FþC visualization and applied it to virtual city models with different levels of structural abstraction. For the viewing of routes, Ziegler and Keim [48] have presented an automated system for generating context-preserving route maps.…”

3D Wayfinding Choremes: A Cognitively Motivated Representation of Route Junctions in Virtual Environments

“…For short routes within a 3D VE, (Degener et al 2008) present an image warping technique to create a single image describing the way. Focus + context visualization as in (Trapp et al 2008) is another way to support wayfinding along routes in 3D VEs. Our approach focuses on the geometric transformation of junctions to conform to the cognitive concept of a route.…”