Abstract
The creation of 3D models of urban elements is extremely relevant for urbanists constituting digital archives and being especially useful for enriching maps and databases or reconstructing and analyzing objects/areas through time, building/recreating scenarios and implementing intuitive methods of interaction. The widespread data available online offer new opportunities to generate realistic 3D models without the need to go physically to the place. This chapter aims to demonstrate the potential 3D modeling and visualization/interaction of urban elements in the city for multiple purposes, and it is organized in four main topics: The first deals with the theoretical framework regarding the bases of the human perception of the spatial environment and the importance of 3D modelling. The second and third deal with technical procedures on terrestrial/aerial data acquisition and demonstrate alternatively data gathered online to generate 3D models for the visualization of urban elements of the city, and the fourth introduces 3D model visualization within an augmented reality environment.
TopTheoretical Framework: Representations, Spatial Environment And Cultural Heritage
Representations play a central role in a cognitive system, supporting perceptions, which are at the basis of how individuals recognize the physical world. The concept of space has been considered an innate organizing principle of the mind, through which the world is, and must be, perceived. Thus, representations are fundamental in the brain, being at the source of all empirical knowledge and conception of the world. People seem to have quite accurate mental representations of their spatial environment, coherently capturing the categorical spatial relations between elements that support perception, reorientation, and spatial inferences (Golledge, 1999). However, mental (internal) representations of the spatial environment diverge from the real world, eliminating and/or adding entities, frequently introducing distortions. Reconstruction generates systematic errors; therefore, humans rely on external representations to serve as cognitive aids for memory and information processing. Visuospatial representations have many similarities to those that reside in the mind. External cognitive tools function to extend the powers of the mind by exploring the human skills at spatial reasoning (Tversky, 2005). These external affordances enhance human cognition and help to understand the spatial environment.
Key Terms in this Chapter
3d Models: Representation of objects based on its position x, y (2D) and z (height).
Volunteered Geographic Information: Phenomenon known as user-generated content. A widespread engagement of large numbers of citizens, often with little in the way of formal qualifications, in the creation of geographic information. They are largely untrained and their actions are almost always voluntary, and the results may or may not be accurate. But, collectively, they represent a valuable set of data about the spatial environment in time.
Mixed Reality: Complements reality/virtuality rather than completely replacing it, appearing to the user that the virtual and real coexist in the same environment.
Augmented Reality: Enrichment of the real world with a complementary virtual world. The digital information or representations are merged with the real view via a device that combines both real and virtual. An AR system expands the real world scene allowing the user to maintain the sense of presence in that world.
Geographic information: Data about places on the Earth's surface. Representations (analog or digital) of the external environment in space and time.
Virtual Reality: Computer generated, interactive, three-dimensional environment in which a person is immersed. Alternative reality (illusionary and represented) that seems to possess all the attributes of reality, truly and objective.
Geographic Information Technologies: The role of technics and tools to acquire, process, store, integrate and visualize geographic information (e.g. Global Navigation Satellite Systems, Geographic Information Systems, Remote Sensing, Unmanned Aerial Vehicles, mobile, apps, 3D, Virtual and Augmented Reality).
Cultural Heritage: Assumes the notion of value and cultural inherency, often related with unicity, rareness, importance, memory, or symbolic representation of one or more specific objects, events, milestones, achievements, or historical significance. Value has always been the reason underlying heritage conservation. However, the notion of valuation might be identified or increased, when supported individually or collectively by processes of extend their intrinsic value.