Design and Implementation of a Web-based Application for the Visualization of Large Scale Photogrammetric and Cartographic Data

The objective of this paper is to show the way multiple source data like aerial photos, maps and descriptive information are combined and amalgamated to form an Internet or Intranet application. The visual outcome is a large scale, precise and detailed image/map displaying the interiors of buildings in a layered fashion, enabling the user to interact with the objects shown on it. Scalable Vector Graphics SVG is an XML language for the encoding/representation of two dimensional vector data, especially designed for integration with other web standards. SVG provides those basic structures, which are needed for map generation and overcomes the disadvantages inherent to bitmap images displaying spatial data. In the domain of spatial data, SVG constitutes a new powerful standard for visualization and has a great potential along with other XML encoding languages like Geographic Markup Language GML, Extensible Stylesheet Language Transformation – XSLT and Cascading Style Sheets – CSS for the development of Webbased applications utilizing open source software and standards. This paper elaborates on the way SVG data is generated from existing cartographic and photogrammetric sources and the use of scripts in order to provide the user with interactive and animation capabilities, resulting to a comprehensive and user friendly map in the Internet. More specifically, photogrammetric data is translated into a neutral format and subsequently to SVG graphics with the utilization of tools that implement this conversion that is carried out separately for the point, line and polygon data, which are subsequently combined into a uniform SVG image. The Graphics User Interface specifically developed for this application, enables the user to select a building from the specified area [i.e. a University campus], to virtually “enter” into the interior of the building and to visualize structural and other information relative with the use of the office space [libraries, laboratories etc] along with the corresponding data for the phone number, IP address etc.