Erik Kjems

GRIFINOR: Integrated Object-Oriented Solution for Navigating Real-Time 3D Virtual Environments

The ability to navigate a 3d virtual environment in real-time has a high priority in connection with different applications for disaster management. This paper presents GRIFINOR — a platform for applications within this area. As a part of GRIFINOR, three new innovations have been promoted. They are presented in this paper as well. In many situations it is important that geoinformation can be accessible for queries within a very short time-frame (minutes). Questions about spatial reasoning and volumetric calculations in connection with different types of simulation has been very dependent on a priori models and very fast computer graphics hardware and software. It is also essential that the features of the model become real objects with attributes etc. Urban 3d models have traditionally been built as wire frame models. This makes it very difficult and in some situations impossible to attach geoinformation to the spatial structure in a way so that it is useful for real-time navigation in 3d. These wire frame models are not suitable for either a connection to a spatial database or for spatial queries. Centre for 3D GeoInformation at Aalborg University, is developing a system that handles 3D data structures as objects with facilities to support real-time geovisualization. The need for a new concept in this area has been one of the major motivations for the development of GRIFINOR. Instead of dealing with simple geometry in a CAD-based environment, GRIFINOR is developed to support object-oriented technology.

Mapping virtual worlds

Metaphors from traditional cartography are very appropriate when constructing and documenting virtual worlds. But it is also a question about developing new methods for multi-dimensional and dynamic mapping of virtual worlds as means for navigationa and way finding.

Managed Objects for Infrastructure Data

Using data objects to describe features in the real world is a new idea and several approaches have already been shown to match scientific paradigms exceedingly well [1, 2, 3]. Depending on the required level of abstraction, it is possible to represent the world more or less closely to reality. In the realm of 3D Geoinformation research, this realism is often related to the way the spatial world is represented. By contrast, the 2D GIS community focuses on attribute data that describes additional states or characteristics of a feature. The main focus in 3D Geoinformation has always been on the representation of spatial objects, on relations like topology, ontology, and on storing and presenting them with more or less detail. The Centre for 3D GeoInformation (3DGI) at Aalborg University is currently participating in a project that explores objects that will not only contain geometry and associated attributive data but also will contain behavioural information. Our goal is to communicate the design and handling of these enhanced objects by means of the concept introduced in Java whereby objects are created in bytecode and subsequently executed within a Java virtual machine. This concept has already been implemented in the GRIFINOR (http://www.grifinor.net) platform [4]. This article will present the core ideas of relevance to this concept as it relates to current understanding of objects. Our work also offers suggestions on how to implemented such algorithms using real-life infrastructure data. Furthermore, we elaborate on the possibilities and challenges associated with moving from mostly static objects to dynamic objects in the area of 3D geoinformation.

VR for decision support in urban planning

Since the beginning of civilization, drawings or models have been produced to illustrate ideas of buildings and development plans. From small cabins to large urban areas architects and planners have used different tools to present and sell their ideas as convincingly as possible. One of the most widespread methods nowadays is the use of artistic posters and small precisely scaled wooden models with nice miniature trees and light arrangements. As beautiful as they may look, they are still downscaled and modelled representations of an idea that has to be interpreted in each spectator’s head. As technology develops and highly specialized visual presentation techniques become affordable, more and more politicians and professionals want to use these techniques for decision support.

A 3D City Model with Dynamic Behaviour Based on Geospatial Managed Objects

One of the major development efforts within the GI Science domain are pointing at real time information coming from geographic referenced features in general. At the same time 3D City models are mostly justified as being objects for visualization purposes rather than constituting the foundation of a geographic data representation of the world. The combination of 3D city models and real time information based systems though can provide a whole new setup for data fusion within an urban environment and provide time critical information preserving our limited resources in the most sustainable way. Using 3D models with consistent object definitions give us the possibility to avoid troublesome abstractions of reality, and design even complex urban systems fusing information from various sources of data. These systems are difficult to design with the traditional software development approach based on major software packages and traditional data exchange. The data stream is varying from domain to domain and from system to system why it is almost impossible to design an unifying system taking care of all thinkable instances now and in the future within one constraint software design complex. On several occasions we have been advocating for a new and advanced formulation of real world features using the concept of Geospatial Managed Objects (GMO). This chapter presents the outcome of the InfraWorld project, a 4 million Euro project financed primarily by the Norwegian Research Council where the concept of GMO’s have been applied in various situations on various running platforms of an urban system. The paper will be focusing on user experiences and interfaces rather then core technical and developmental issues. The project was primarily focusing on prototyping rather than realistic implementations.

3D Geo-Information Sciences

Keynotes.- A Virtual Geographic Environment for a Simulation of Air Pollution Dispersion in the Pearl River Delta (PRD) Region.- Representing and Exchanging 3D City Models with CityGML.- Research and Development Program for the Third National Geographic Information System Project in Korea: Korean Land Spatialization Program.- Papers.- Construction Operators for Modelling 3D Objects and Dual Navigation Structures.- A Multilayered Space-Event Model for Navigation in Indoor Spaces.- Towards Defining a Framework for Automatic Generation of Buildings in CityGML Using Building Information Models.- Managed Objects for Infrastructure Data.- Integrating Terrain Surface and Street Network for 3D Routing.- Using a B-Rep Structure to Query 9-Intersection Topological Relationships in 3D GIS - Reviewing the Approach and Improving Performance.- Query Processing in 3D Spatial Databases: Experiences with Oracle Spatial 11g.- Making Interoperability Persistent: A 3D Geo Database Based on CityGML.- Use of Finite Arithmetic in 3D Spatial Databases.- Automatic Digital Aerial Image Resection Controlled by LIDAR Data.- Automatic Surface Patch Generation from a Video Image Sequence.- Indoor 3D Modeling and Visualization with a 3D Terrestrial Laser Scanner.- Automatic Image Mosaic-Building Algorithm for Generating Facade Textures.- 3D Continuous K-NN Query for a Landmark-based Wayfinding Location-based Service.- 3D Geo-Network for Agent-based Building Evacuation Simulation.- Hierarchical Modelling of Multi-Geospatial Databases as Basis for Geo-Oriented 3D Analysis Capabilities.- Solar Radiation over the Urban Texture: LIDAR Data and Image Processing Techniques for Environmental Analysis at City Scale.- Creation and Error Analysis of High Resolution DEM Based on Source Data Sets of Various Accuracy.- A Topological Analysis Method for 3D Geo-Entities Structured as Hexahedron Tessellations.- Constraint-based Generation and Visualization of 3D City Models.- GeoVEs as Tools to Communicate in Urban Projects: Requirements for Functionality and Visualization.- Producing 3D Applications for Urban Planning by Integrating 3D Scanned Building Data with Geo-spatial Data.- 3D Dynamic Simulation and Visualization for GIS-based Infiltration Excess Overland Flow Modelling.A complete methodology from the extraction of Light Detection and Ranging (LIDAR) data to the environmental analysis of urban models and the visualization of results is presented. Aim of t he work is to establish a process to investigate digital urban models integra ting cross-disciplinary competences, like remote sensing, GIS, image proces sing and urban and environmental studies. Toward this goal, working on several interfaces, tools and datasets was necessary to provide a conse quent structure to the introduced methodology. Case study for application was a squared area 300 m etres wide in central Geneva where LIDAR data are available. The us of a hybrid approach from raw LIDAR data and vectorial digital maps (GIS data) of buildings footprints for the interpolation of a 2.5 -D urban surface model, with a resolution grid of 0.50 by 0.50 metres, allo wed to refine vertical