GeoVEs as Tools to Communicate in Urban Projects: Requirements for Functionality and Visualization
Lecture Notes in Geoinformation and Cartography
Urban planning is a complex decision-making process involving a large number of actors who interact intensively. Such groups often have conflicting expectations and backgrounds. Therefore, consultation and interaction is vital for the success of urban projects. A Geo-Virtual Environment (geoVE) can play an important role as a communication tool in the field of spatial planning, but such tools are still in limited use. We investigate the requirements for visualization in urban planning by
... ng user perceptions of visual materials and their needs for interaction in the different urban phases. The study is completed with the cooperation of several large municipalities in the Netherlands. Taxonomy of geoVE functionalities & visualization materials for interaction in urban planning A Geo-Virtual Environment is broadly defined as a spatially referenced digital world that comprises visual (and non-visual) objects in an immersive and interactive 3D scene to represent and mimic reality through dynamic real-time simulation. Zlatanova et al. (2007) mention that 3D VR models provide flexibility in interaction and exploration. These models include active and passive interaction functionalities for users. Functionalities of geoVE There have been several attempts to define the functionalities of geoVEs. Heim (1998) defined the so-called I-factors of Immersion, Interactivity and Information Intensity (or Levels of Detail, LoD). MacEachren et al. (1999) added the I-factor of Intelligence (of Objects). Wachowicz (2002) and Lammeren & Hogerwerf (2003) tried to extend this classification. Adopting some of these developments, we introduce a classification of geoVEs for urban planning with respect to construction, capabilities, experience, controlling, interacting, exploring and components. Construction: This functionality refers to the system architecture of a geoVE and the type of data used to build a 3D scene. The construction of the 3D scene is inseparable from the scale and resolution of the 3D data. These are often defined as Levels of Details (LoD). In urban planning, LoD can also be used to create different 'visual materials' (see Section 2.2). Different types of data can be integrated in a 3D scene through a data-fusion. The data for the 3D scene can be stored in Relational Database Management Systems (RDBMS) or other databases and visualized 'onthe-fly' in the geoVE. Capabilities: The capability domain consists of functionalities related to the interface of the geoVE; it enables users to interact with the interface, 3D models and attribute information. The foremost capability of the ge-oVE is representation and rendering capability. Visual representation deals with visual contents like color, texture, shape, rendering and geometry. The same model can be visualized in various representations, by changing the line types, thicknesses, transparencies, colours and textures of the model. Fig. 1 shows the 'Poptahof Urban Design' project in different representations keeping the same geometry. There can also be multiple representations where different 3D models (containing different geometries) are used to represent different design solutions on a single site. Fig. 2 illustrates the study of alternative geometry models of Poptahof Urban Project, Delft using same representation in geoVE to avoid bias. Multi-dimensionality refers to the possibility that the objects in a geoVE can be visualized as text, 1D points, 2D images, graphs, maps and 3D models. Muti-layering enables various layers to be added. The capabilities of simulations trigger change in the 3D-scene by pre-defined algorithms. Animations are pre-recorded simulations usually used in presentation.