Adaptive grids towards interactive tourist map deformation

Abstract

In tourism studies, it is considered that a tourist map has three basic functions: discover potential points-of-interest (POI), plan routes and give spatial information. In the age of ubiquitous mobile devices and digital maps, it is essential that these functions be implemented in modern maps in addition to dynamic and interactive views customized to users. Additionally, increasing trends of online map personalization demands real-time task-dependent map representations enabled by map deformation. Prior map deformation techniques mainly based on uniform grids can be insufficient for such real-time demands. For higher flexibility of allocating resolutions, using an adaptive approach is needed. An initial investigation on adaptive approach with deforming models is performed in the context of view-dependent rendering integrated with occlusion culling for large-scale crowd scenes. To provide varying resolutions on each articulated model, it is proposed to use a cluster hierarchy in the view-dependent representation. The cluster hierarchy, constructed by adaptively clustering regions with similar significance values in terms of simplification quality, results in a high quality simplification that can achieve interactive performance. Lessons from deforming models are applied to map deformation. A proposed content-aware non-uniform grid leads to adaptive resolutions on the map deformation. In other words, finer subdivisions on more significant regions such as guide road patterns, and coarser subdivisions with less quad edges on less significant regions are applied. This adaptive approach results in both higher road deformability and performance. Finally, a dynamic and interactive tourist map application is demonstrated. An interactive framework that holistically combines presentations of a POI map and a metro network, helping users identify popular POIs based on visual worth computation, and discover POIs within reach of a metro. Octilinear layouts are used to highlight the metro network, and representative POI images are shown in layout space visualized within a user-specified viewing window.