XVIIIth Congress: XVIIIth Congress

Kraus, Karl; Waldhäusl, Peter

Bibliographic data

Multivolume work

Persistent identifier:: 1667435949

Title:: XVIIIth Congress

Sub title:: Vienna, Austria 1996

Year of publication:: 1996

Place of publication:: Vienna

Publisher of the original:: Austrian Society of Surveying and Geoinformation

Identifier (digital):: 1667435949

Language:: English

Editor:: Kraus, Karl; Waldhäusl, Peter

Corporations:: International Society for Photogrammetry and Remote Sensing, Congress, 18., 1996, Wien; International Society for Photogrammetry and Remote Sensing

Adapter:: International Society for Photogrammetry and Remote Sensing, Congress, 18., 1996, Wien; International Society for Photogrammetry and Remote Sensing

Founder of work:: International Society for Photogrammetry and Remote Sensing, Congress, 18., 1996, Wien; International Society for Photogrammetry and Remote Sensing

Other corporate:: International Society for Photogrammetry and Remote Sensing, Congress, 18., 1996, Wien; International Society for Photogrammetry and Remote Sensing

Document type:: Multivolume work

Volume

Persistent identifier:: 1667438379

Title:: XVIIIth Congress

Scope:: 449 Seiten

Year of publication:: 1996

Place of publication:: Vienna

Publisher of the original:: Austrian Society of Surveying and Geoinformation

Identifier (digital):: 1667438379

Illustration:: Illustrationen, Diagramme

Signature of the source:: ZS 312(31,B2)

Language:: English

Additional Notes:: Erscheinungsdatum des Originals ist anhand des Copyrightjahrs ermittelt.

Usage licence:: Attribution 4.0 International (CC BY 4.0)

Editor:: Kraus, Karl; Waldhäusl, Peter

Corporations:: International Society for Photogrammetry and Remote Sensing, Congress, 18., 1996, Wien; International Society for Photogrammetry and Remote Sensing; International Society for Photogrammetry and Remote Sensing, Commission Instrumentation for Data Reduction and Analysis

Adapter:: International Society for Photogrammetry and Remote Sensing, Congress, 18., 1996, Wien; International Society for Photogrammetry and Remote Sensing; International Society for Photogrammetry and Remote Sensing, Commission Instrumentation for Data Reduction and Analysis

Founder of work:: International Society for Photogrammetry and Remote Sensing, Congress, 18., 1996, Wien; International Society for Photogrammetry and Remote Sensing; International Society for Photogrammetry and Remote Sensing, Commission Instrumentation for Data Reduction and Analysis

Other corporate:: International Society for Photogrammetry and Remote Sensing, Congress, 18., 1996, Wien; International Society for Photogrammetry and Remote Sensing; International Society for Photogrammetry and Remote Sensing, Commission Instrumentation for Data Reduction and Analysis

Publisher of the digital copy:: Technische Informationsbibliothek Hannover

Place of publication of the digital copy:: Hannover

Year of publication of the original:: 2019

Document type:: Volume

Collection:: Earth sciences

Chapter

Title:: A DATABASE FOR A 3D GIS FOR URBAN ENVIRONMENTS SUPPORTING PHOTO-REALISTIC VISUALIZATION Michael Kofler, Herwig Rehatschek, Michael Gruber

Document type:: Multivolume work

Structure type:: Chapter

A DATABASE FOR A 3D GIS FOR URBAN ENVIRONMENTS SUPPORTING PHOTO-REALISTIC VISUALIZATION Michael Kofler, Herwig Rehatschek, Michael Gruber Institute for Computer Graphics Graz Technical University Austria {kofler,herwig,gruber}@icg.tu-graz.ac.at Commision Il, Working Group 2 KEY WORDS: GIS, Urban, Database, Visualization, Three-dimensional ABSTRACT As 3D GISs (geographical information systems) become increasingly important, new database technologies are needed. This paper presents ideas about requirements for a 3D GIS database for urban environments. A high emphasis is given to the support of a fast photo-realistic visualization, thus expanding the scope of functions offered by traditional GIS databases. Required functions to allow an efficient visualization are: e Perspective querying (to extract all objects of the database located a pyramid of vision). e Support of the level of detail concept on database level (to extract objects in varying detail according to the size of the objects on screen). e Image compressing/decompressing/caching (to offer a scale-able compromise between speed and data volume). KURZFASSUNG Mit der zunehmenden Bedeutung dreidimensionaler geografischer Informationssysteme (3D GIS) zeichnet sich die Notwendigkeit neuer Datenbanktechnologien ab. Herkómmliche GIS-Datenbanken sind insbesondere da überfordert, wo es um die schnelle Visualisierung der Daten geht. Erforderliche neue Funktionen sind: e Perspektivische Abfragen (um alle Objekte zu ermitteln, die momentan sichtbar sind). e Unterstützung des Level-of-Detail-Konzepts (um Objekte je nach ihrer aktuellen Größe am Bildschirm in unterschiedlichen Qualitátsstufen zur Verfügung zu stellen). e Automatische Komprimierung / Dekomprimierung von Bildern. 1 INTRODUCTION / MOTIVATION 2 RELATED WORK An increasing number of users of GISs for urban environments This section summarizes some recent papers on rendering asks for 3D extensions ([SBM 94], [RG 95]): and storing complex geometrical models. All papers present ideas to improve the LOD (level of detail) concept, which will be crucial for any 3D GIS application supporting inter- active photo-realistic rendering. LOD is a mechanism used in computer graphics to improve the drawing speed of com- plex scenes [Cla 76]: Each object is stored several times in different levels of quality (levels of detail). During visualiza- tion each object is drawn in the optimal level of detail. The : à chosen level depends on the size of the object in the current e Tourism agencies want to offer virtual reality models of View. Objects that appear small can be drawn in little detail destinations they are offering. (and therefore very fast) without loosing quality; in contrast, The step from 2D to 3D causes several problems, which can objects near the point of view that cover a lot of space on be summarized in three points: building 3D models, storing | the screen need to be rendered in full quality. e Scientists want to simulate noise, heat and exhaust spreading in big cities. e Telecommunication companies need 3D data to calculate wave propagation in urban environments. e Architects want photo-realistic models of existing build- ings to plan new ones and to visualize the resulting scenery. them and providing a user interface to visualize and manip- Although the LOD idea is quite old and lots of applications ulate them. This paper is focused on the latter two points. ke use of it, several problems remain unsolved. The most It discusses techniques to store and visualize huge 3D data urgent one is probably building LOD models: although sev- sets. eral scene editors already support the LOD concept, none is Currently, two research groups are working on this topic: on able to build LODs automatically in good quality yet. There- the one side, maintainers and developers of GISs are trying fore, most existing LOD models are still built manually, thus to expand their 2D systems with 3D features. On the other increasing the already high cost of creating a model at all. side, lots of efforts come from computer graphics experts, [HG 94, SS 95] explain algorithms for building lower levels of who want to visualize scenes of growing complexity faster detail from a given 3D model in high quality. Until now, these and faster. algorithms have been restricted to polygonal models and do NS : : i h Unfortunately, there is little interconnection between these not deal with textures, though two groups. This paper tries to fill this gap. It gives an In its original concept LODs offer different geometric rep- overview of recent research activities (section 2), points out resentations for one object. [MS 95] propose two improve- requirements to a 3D GIS database for urban environments ments: (1), the LOD concept can be adapted to store the (section 3) and discusses issues of implementation (section entire model (e.g. a city) in one hierarchical structure. (2), 4). The paper ends with a short outlook (section 5) and 'impostors' replace traditional LODs: Impostors are very simi- some references. lar to LODs; they are more versatile as they include additional 198 International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B2. 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