Title: The use of Multipatch for the objects in 3D Digital Cartography

Name and surname of 1st author: Eufemia Tarantino E-mail e.tarantino@poliba.it

Organization to which author(s) belong: Polytechnic University of Bari - ITALY

Conference Theme considered appropriate for the contents of the presentation:

5. Digital Cartography and GIS for Sustainable Development of Territories.

Other authors (name, surname and e-mail):

Mauro Caprioli E-mail m.caprioli@poliba.it

Benedetto Figorito E-mail benedetto1980@libero.it

Alfredo Scognamiglio E-mail a.scognamiglio@poliba.it

ABSTRACT

The 3D geographic information has now become fundamental in analysis of many socio–environmental problems. For some application fields the simple 3D data visualization is required, but the 3D complex objects can be considered as great aid in territorial analysis connected to specific areas, such as in telecommunications or in landscape studies.

In order to meet such requirements, the last generation CAD softwares have improved the editing and the photorealistic visualization of objects for mechanics and industrial fields, whereas GIS softwares, with the use of georeferenced points, lines and polygons, have emphatically developed tools for spatial analysis of objects. So far, with visualization tools based on simple extrusions, both the technologies doesn’t permit structuring of 3D topological models and visualization of complex entities.

All the 3D vector data models have in common the set of geometric primitives structured in different way for a specific application. In literature the are substantially object oriented and topology oriented models. In the first one, addressed to visualization, topology and spatial relations are derived from the object structure, while in the second one, connected to analysis, relations are explicitly defined between one object and its neighbours.

With this study the 3D cartographic data acquisition will be evaluated, in order to allow spatial processing in 3D GIS environments, also divulged by web. Particular attention will be made on the potentiality of the CAD-GIS tandem using the feature type Multipatch with distinct softwares.

The Multipatch permits to encapsulate complex objects in a compact way and to add also textures on surfaces, providing a real objects visualization. Such technique isn’t still used because commercial GIS softwares haven’t specific tools to create feature 3D Multipatch.

The processing expected in this research for the creation of Multipatch will be executed with the aid of some commercial softwares, such as ArcScene–ArcInfo 9.1, SketchUp5 e AutoCAD 2006 to investigate the real possibility to use this methodology from Cartography producers. The objects made with different procedures will be visualized in ArcScene – ArcInfo 9.1 environment, verifying the next effective possibility of thematic queries.