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Commission VI, WG VI/4KEY WORDS: Urban Landscape Protection, LIDAR Data, 3D City Models, CityGML, Computational Urban Analysis, Tall Buildings ABSTRACT:In contemporary town planning protection of urban landscape is a significant issue. It regards especially those cities, where urban structures are the result of ages of evolution and layering of historical development process. Specific panoramas and other strategic views with historic city dominants can be an important part of the cultural heritage and genius loci. Other hand, protection of such expositions introduces limitations for future based city development. Digital Earth observation techniques creates new possibilities for more accurate urban studies, monitoring of urbanization processes and measuring of city landscape parameters. The paper examines possibilities of application of Lidar data and digital 3D-city models for: a) evaluation of strategic city views, b) mapping landscape absorption limits, and c) determination protection zones, where the urbanization and buildings height should be limited. In reference to this goal, the paper introduces a method of computational analysis of the city landscape called Visual Protection Surface (VPS). The method allows to emulate a virtual surface above the city including protection of a selected strategic views. The surface defines maximum height of buildings in such a way, that no new facility can be seen in any of selected views. The research includes also analyses of the quality of simulations according the form and precision of the input data: airborne Lidar / DSM model and more advanced 3D-city models (incl. semantic of the geometry, like in CityGML format). The outcome can be a support for professional planning of tall building development. Application of VPS method have been prepared by a computer program developed by the authors (C++). Simulations were carried out on an example of the city of Dresden.

The article provides a preliminary analysis of selected factors that influence city visual perception, in particular tall buildings, in the cityscape. The research area includes selected European cities of a diverse urban structures and cityscape types. The cities also represent various strategies for the development of tall buildings. The article discusses tall building observation parameters, perception conditions and urban composition and geometry. It also describes techniques of digital cityscape analysis used by the author in her planning practice.

Commission VI, WG VI/4KEY WORDS: Tall Buildings, 3D Isovists, Visual Impact, LIDAR, 3D City Models, Computational Urban Analysis. ABSTRACT:The paper examines possibilities and limitations of application of Lidar data and digital 3D-city models to provide specialist urban analyses of tall buildings. The location and height of tall buildings is a subject of discussions, conflicts and controversies in many cities. The most important aspect is the visual influence of tall buildings to the city landscape, significant panoramas and other strategic city views. It is an actual issue in contemporary town planning worldwide. Over 50% of high-rise buildings on Earth were built in last 15 years. Tall buildings may be a threat especially for historically developed cities -typical for Europe. Contemporary Earth observation, more and more available Lidar scanning and 3D city models are a new tool for more accurate urban analysis of the tall buildings impact. The article presents appropriate simulation techniques, general assumption of geometric and computational algorithms -available methodologies and individual methods develop by author. The goal is to develop the geometric computation methods for GIS representation of the visual impact of a selected tall building to the structure of large city. In reference to this, the article introduce a Visual Impact Size method (VIS). Presented analyses were developed by application of airborne Lidar / DSM model and more processed models (like CityGML), containing the geometry and it's semantics. Included simulations were carried out on an example of the agglomeration of Berlin.

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