The Hellenistic city model inspired by Koolhaas: A test case for a generic city model (original) (raw)
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The Hellenistic City Model Inspired by Koolhaas
In this paper, we suggest a generic city description model suited for purposes like semi-automatic city modeling and urban layout evaluation. The generic city model refers to basic vital functions of a (computable) city. Feature patterns are used to extend the generic city model with global and local characteristics. The Hellenistic cities serve as a platform for a first implementation to test a semi-automatic city model generation. As a result four cities are reconstructed as a first example of our ongoing work, Miletus, Knidos, Priene and Olynthus. Future work will deal with the application of the generic city model to the performance simulation of contemporary urban layouts.
City Models--Automation in Research and Practice
2001
This paper concentrates on the role of automated extraction of city models in today's practical work. The state of research and practical implementations is compared and the question is raised why the degree of automation in modelling systems is still very low -despite many years of scientific research efforts. Some of the problems are identified, in particular the need to achieve a high degree of automation and to assess the advantage of automatic components by looking at the effects on the entire processing chain rather than only single stages. Three examples for automation are given. The first two are approaches for the reconstruction of building geometry which integrate 2D ground plan information with digital surface models. A heuristic subdivision of ground plans into rectangles as well as a rule-based reconstruction relying on discrete relaxation and constrained tree search are discussed. The third example shows how quality control can be automated using digital surface models.
CyberCity Modeler, a tool for interactive 3-D city model generation
Cybercity Modeler (CC-Modeler) is a semi-automated generator for 3-D objects of built-up environments. Given the primary data as point clouds measured on Analytical Plotters or Digital Stations, CC-Modeler presents a new method for fitting planar structures to the measured sets of point clouds. While this topology generator has been originally designed to model buildings, it can also be used for other objects, which may be approximated by polyhedron surfaces. We have used it so far for roads, rivers, parking lots, ships, etc. CC-Modeler is a generic topology generator. The problem of fitting planar faces to point clouds is treated as a Consistent Labeling problem, which is solved by probabilistic relaxation. Once the faces are defined and the related points are determined, a simultaneous least squares adjustment is applied in order to fit the faces jointly to the given measurements in an optimal way. We first present the processing flow of CC-Modeler. Then, the algorithm of structuring the 3-D point data is outlined. Finally, we show the results of several data sets that have been produced with CC-Modeler. Also, reference is made to a new concept for a spatial information system (CC-SIS, CyberCity Spatial Information System)which is currently under development.
A Working Session on 3-D City Modeling
On the occasion of a presentation on a city model for Graz at the eCAADe-conference in Weimar (2000), some attendees informed us about their previous work in this field and the idea of preparing a working session with collegues involved in 3-D city modeling was born. During the initial phase of research for this eCAADe conference activity it turned out that a large number of city models has been created in the course of time for different reasons resp. purposes. Therefore a rich variety in the production of city models can be noticed. This working session on 3-D city modeling brings together experts focusing on different aspects concerning the creation and use of city models, such as data input, data structure, data storage and data quality. Also the definition of a perspective on the future of 3-D city modeling can be regarded as an important topic. In this paper a rough overview on the different submissions will be presented. Furthermore three blitz statements are incorporated as time was too short to produce a full paper. Both with the individual contributions as with this overview paper it is intended to present a knowledge-base to this working field. Finally, the start for a growing bibliography was made in order to support future work in this area.
eCAADe proceedings
In this paper we present an outline of a newly started project to develop a city generator for use in urban planning. The aim of the project is to develop a rule-based system which is capable of generation lookalike cities. Lookalike cities are cities which resemble real life cities without being an exact copy of it. A city consists of several zones; each zone has it own identity. In order to generate lookalike cities, these zone-identities need to be capture into rules which the system can 'read'.
Procedural city layout generation based on urban land use models
2009
Abstract Training and simulation applications in virtual worlds require significant amounts of structurally plausible urban environments. Procedural generation is an efficient way to create such models. Existing approaches for procedural modelling of cities aim at facilitating the work of urban planners and artists, but either require expert knowledge or external input data to generate results that resemble real-life cities, or they have long computation times, and thus are unsuitable for non-experts such as training instructors.
Towards fully automated 3D city model generation
Three-dimensional city models are usually comprised of a description of the terrain, streets, buildings and vegetation in build-up areas. Building models are an important part thereof, even though it has to be noted that for many applications, additional information is necessary. For example, a faithful representation for virtual reality applications can only be obtained when the texture of the ground, roofs and façades is present and important details like trees, walkways and fences are present .
Interactive Reconfiguration of Urban Layouts
IEEE Computer Graphics and Applications, 2000
T he ability to create, extend, and change a model of a large-scale urban environment is useful for a variety of computer graphics applications. For example, it lets urban planning applications simulate changes to city layouts or newly proposed neighborhoods, create hypothetical views of an urban area after applying development and growth algorithms, and show architects the results of using common building blocks to design a new city layout. Emergency-response simulations can train personnel in current and speculative urban layouts, including planning evacuation routes for various catastrophes, and can suggest emergency deployments of communication networks, resources, and policing. Finally, reconnaissance applications can visualize and analyze existing cities for which only partial information is known. The structural characteristics of a historically significant region are important aspects of urban visualization. Capturing the layout of an urban space in images (for example, satellite and aerial photographs) loses the layout's structural information, which can then no longer be exploited. An urban layout consists of a complex collection of man-made structures arranged in roads, parcels, city blocks, and neighborhoods. Applications can treat the content as unstructured images and use current image-processing tools to change the images or generate similar imagery synthetically. However, this yields undesirable results, including deformations and structural discontinuities. Or, applications can assume the Graphics (Proc. Siggraph), vol. 26, no. 3, 2007. H. Zhou et al., "Terrain Synthesis from Digital Elevation Models,"
For a better visual impression, three-dimensional (3D) information systems and landscape architectures need photo-realistic visualization of detailed 3D datasets. But easy accessibility with efficient rendering becomes difficult due to the detailed data associated with 3D objects. Therefore, different applications demand different levels of detail (LoD). A single generalization method cannot be applied to remove or preserve different pieces of building information on a certain LoD. Additionally, different generalization strategies produce different results for generalized models. Therefore, the aim of this thesis is to contribute the state-of-the-art in 3D generalization methodologies. This thesis proposes a 3D generalization framework based on a three-step (projection, generalization and reconstruction) strategy to generate less-detailed and more abstract representation of buildings modelled in the City Geography Markup Language (CityGML). The proposed strategy focuses specifically on simplification and aggregation of building footprints based on point-reduction, edge-removal and small circle strategies. Furthermore, vertex reduction method for simplification of complex shapes of building footprints is one of the contributions to the scientific field of 3D Geographic Information System (GIS). Experiments and results of the thesis show that 3D generalization based on the CityGML generalization specifications can avoid removal of important features of a building and fulfill the demands of task specific applications. Furthermore, mostly, data reduction is directly proportional to the length of edges as threshold value. However, the data volume of the generalized models is 10.5% for 4 meters and 30.62% for 6 meters threshold values. About 37.65% of data is reduced after generalization at LoD1 CityGML model as compared to 30.18% at LoD2. Furthermore, 3.31% boundary of building footprints of Putrajaya at 5 meters threshold value is observed as eliminated despite removing 52% smaller edges. The authenticity of generalized models is evaluated based on a comparison of similarity between original and generalized boundaries of building footprints. The proposed generalization strategy could be extended to generalize a group of buildings and maintain topological relationship among generalized LoDs.