Hagedorn, Benjamin; Maass, Stefan; Döllner, Jürgen
4th International Symposium on LBS and Telecartography
Visualization of 3D geovirtual environments enables users to gain insight into and to interactively operate with complex 3D geoinformation as well as to explore and analyze underlying structures, relationships, and associated thematic georeferenced data. It represents a key functionality for a growing number of applications and systems such as for way-finding, urban city planning, geo-marketing, and tourist information. For the systematic implementation of these systems, geoinformation services provide an interoperable and standardized way to access, process, and view distributed, heterogeneous 2D and 3D geospatial data. To broaden the use and scope of 3D geovirtual environments, we have to support the management and visualization of user-defined or application-defined data associated with geospatial objects. For this purpose, we can embed annotations such as texts or symbols as meta elements into images of 3D geovirtual environments. For example, annotations can represent georeferenced comments added interactively by the user to explicitly denote spatial objects and locations the comments refer to. This paper presents the design of a chain of web services for the creation of annotated perspective views. First, a Web Perspective View Service (WPVS) is outlined that synthesizes images of a given 3D geovirtual environment and delivers the images to the service consumer. Second, the Web View Annotation Service (WVAS) is introduced that processes these images as input along with a set of spatial locations and content definitions. To ensure high legibility, annotations are embedded into the view plane and placed such that they avoid occlusions among themselves and with geospatial objects of the scene. As result of this service composition, the service consumer receives an enhanced image depicting the current perspective view with seamlessly embedded annotations. We describe the design and system architecture by the example of a prototypic interactive campus information system.