Martin Breunig

Review: 3D geo-database research: Retrospective and future directions

3D geo-database research is a promising field to support challenging applications such as 3D urban planning, environmental monitoring, infrastructure management, and early warning or disaster management and response. In these fields, interdisciplinary research in GIScience and related fields is needed to support the modelling, analysis, management, and integration of large geo-referenced data sets, which describe human activities and geophysical phenomena. Geo-databases may serve as platforms to integrate 2D maps, 3D geo-scientific models, and other geo-referenced data. However, current geo-databases do not provide sufficient 3D data modelling and data handling techniques. New 3D geo-databases are needed to handle surface and volume models. This article first presents a 25-year retrospective of geo-database research. Data modelling, standards, and indexing of geo-data are discussed in detail. New directions for the development of 3D geo-databases to open new fields for interdisciplinary research are addressed. Two scenarios in the fields of early warning and emergency response demonstrate the combined management of human and geophysical phenomena. The article concludes with a critical outlook on open research problems.

An approach to the integration of spacial data and systems for a 3D geo-information system

Abstract Spatial queries for 3D geo-information systems are analysed and mapped into different abstraction levels of space. The integration of spatial representations is seen as a central task for the integration of 3D data in geo-information systems. A simplicial complex approach is presented that facilitates the unified representation of irregular geo-objects in 3D Euclidean space. Convex simplicial complexes are introduced that help to overcome the complexity of 3D-algorithms. First experiences with the data and systems integration for a 3D geo-information system are presented in a collaborative research centre at the University of Bonn. GeoToolKit, an open 3D database kernel system implemented by using the object-oriented database management system ObjectStore® has been realized to serve in future as a software platform for an open environment of component-based geo-services. It provides geometric 3D algorithms, spatial access methods and a 2D/3D-visualization in order to support the 3D geoscientific modeling.

From GeoStore to GeoToolKit: The Second Step

Todays geo-information systems are closed systems mainly supporting geographic tasks in 2D space. In new spatial application areas such as environmental research, geology, city planning or telecommunications, however, a database and processing support for 3D/4D objects is required. Thus the development of object-oriented 3D/4D modelling and data handling components for geo-information systems is a new challenge. We first report on our experience with GeoStore, an information system already in use for the management of geologically defined geometries. We then follow the way from GeoStore to the design of GeoToolKit, an object-oriented geo-database kernel system for the development of 3D/4D applications. GeoToolKit supports object-oriented modelling of geo-applications, spatial data maintenance within an ODBMS including spatial indexing and the 3D-visualization of spatial objects and query results. Conversely, we also present the reconstruction of a geological application on top of GeoToolKit. Finally we give an outlook on our GeoToolKit research within an open component based environment of geo-information services.

First Experiences with GEOSTORE, an Information System for Geologically Defined Geometries

Since the beginning of 1993 our group is a member of the SFB “Interactions of Continental Substance-Systems and their Modelling” 1. In this interdisciplinary project about 20 groups of the University of Bonn, mainly geoscientists, are participating. To provide the SFB with database technology as soon as possible, we decided to develop GEOSTORE, a first prototype system which is restricted on the management of geologically defined geometries such as 3D-points and triangulated 3D-surfaces of geological layers and faults. The functionality of GEOSTORE includes the management of three dimensional geological surfaces, the checking of spatial integrity constraints, the 2D-visualization of the examinated area in the Lower Rhine Embayment and a 2D-visualization of horizontal and vertical intersections with 3D-faces. GEOSTORE has first been realized on top of a relational DBMS and secondly on top of an ODBMS. For the 3D-visualization of the geological layers and faults a coupling with GEOCON, a 3D-construction and modelling tool for geological surfaces, is realized via remote procedure call.

The Story of the GeoToolKit—An Object-Oriented Geodatabase Kernel System

The quickly increasing number of spatio-temporal applications in fields like environmental monitoring, geology and mobile communication is a new challenge to the development of geodatabases. However, the query functionality of todays geo-information systems is still limited to the thematic attributes of spatial objects and to spatial 2-D objects. This article reports on GeoToolKit, an object-oriented geo-database kernel system developed at Bonn University to support 3-D/4-D geological applications. GeoToolKit is not a GIS-in-a-box package, but rather a library of C ++ classes that allows the incorporation of spatio-temporal functionality within an application. Being a component toolkit, it encourages the development and deployment of re-usable and open software. The history, concepts and implementation of GeoToolKit are discussed in detail. Performance tests underline the practicability of the concepts. Extensions to and experiences with GeoToolKit applications like GeoStore, GeoWeb and WellStore are presented. Finally, we give an outlook on our future research introducing GeoToolKit as a 3-D/4-D database component within a network of distributed and mobile geo-information services.

Chapter 7: Architectures and Implementations of Spatio-temporal Database Management Systems

This chapter is devoted to architectural and implementation aspects of spatiotemporal database management systems. It starts with a general introduction into architectures and commercial approaches to extending databases by spatiotemporal features. Thereafter, the prototype systems Concert, Secondo, Dedale, Tiger, and GeoToolKit are presented.

First steps towards an interoperable GIS — an example from Southern Lower Saxony —☆

Abstract In geosciences the necessity of combining geological and geophysical information as well as applying tools for designing 3D geological and geophysical models is well accepted. Nevertheless, in most cases this demand is only put into practice by file transfer between the applications. The creation of a common 3D model is complicated by the inflexible handling of new and reinterpreted data and by changing applications, heterogeneous operating systems and/or hardware platforms. We present a new approach for a component based GIS which is coupled with an object oriented database management system. The original data, as well as the derived data and the 3D models, are stored in the extensible database. Geological and geophysical 3D modeling tools have direct access to the database via the Common Object Request Broker Architecture (COREA). By this means, we obtained both the integration of the software components and independence from changing software applications and changing platforms, finally resulting in an interoperable 3D GIS.

Space-time modelling of the Lower Rhine Basin supported by an object-oriented database

Abstract Within the framework of the Collaborative Research Centre (CRC, SFB 350) at Bonn University, dealing with interacting geological processes in continental regimes, a joint 3D/4D GIS project is developed by geologists and computer scientists. When analysing and modelling the structural and sedimentary evolution of the Cenozoic intracratonic Lower Rhine Basin in NW Germany, the need emerged to combine methods and tools of space-time modelling of geologically defined geometries with advanced database management techniques. Computer aided geological design typically requires operations for storage and retrieval of large 3D data sets together with their attributes and topological relations and for the generation of model surfaces of stratigraphic boundaries and faults, which in turn define the boundaries of geological bodies developing in time. The requirements of interactive visualisation, analysis and modification of complex and time dependent geometries entail the demand for spatial, topological and time-related database queries as well as for various consistency and integrity tests. Considering these specific geological requirements, an object-oriented geo-database kernel system has been designed and implemented as a “GeoToolKit” for 3D/4D geoscience applications.

New methods for topological clustering and spatial access in object-oriented 3D databases

The data handling component of todays geographical information systems still only considers the management of two-dimensional data. However, in the geosciences as well as in commercial planning fields there is an increasing need to manage large amounts of 2.5D- and 3D-data. On the one hand, mobile telephony providers require digital landform data to maintain overall communication service networks. On the other hand, geoscientists and engineers need 3D surface and solid data to research dynamic processes. We are presenting new methods for the efficient spatial access and the phiysical clustering of 3D geometries according to their topology. These methods enable acceptable performance for users, not only during the filter step of spatial queries but also during the refinement on exact geometries. The methods are evaluated and embedded into GeoToolKit, our database kernel system for 3D application.

Modelling and Managing Topology in 3D Geoinformation Systems

Modelling and managing topology in 3D GIS is a non-trivial task. The traditional approaches for modelling topological data in 2D GIS cannot be easily extended into higher dimensions. In fact, the topology of real 3D models is much more complex than that of the 2D and 2.5D models used in classical GIS; in consequence there is a great number of different 3D spatial models ranging from constructive solid geometry to boundary representations. The choice of a particular representation is generally driven by the requirements of a given application. Nevertheless, from a data management point of view, it would be useful to provide a general topological model handling 2D, 2.5D and 3D models in a uniform way. In this paper we describe concepts and the realisation of a general approach to modelling and managing topology in a 3D GIS based on oriented d-Generalised Maps and the closely related cell-tuple structures. As an example of the applicability of the approach, the combination of a group of buildings from a 3D city model with the corresponding part of a 2D city is presented. Finally, an outlook to ongoing research is given in the context of topological abstraction for objects represented in multi-representation databases.