Integrated modelling for 3D GIS

A three dimensional (3D) model facilitates the study of the real world objects it represents. A geoinformation system (GIS) should exploit the 3D model in a digital form as a basis for answering questions pertaining to aspects of the real world. With respect to the earth sciences, different kinds of objects of reality can be realized. These objects are components of the reality under study. At the present state-of-the-art different realizations are usually situated in separate systems or subsystems. This separation results in redundancy and uncertainty when different components sharing some common aspects are combined. Relationships between different kinds of objects, or between components of an object, cannot be represented adequately. This thesis aims at the integration of those components sharing some common aspects in one 3D model. This integration brings related components together, minimizes redundancy and uncertainty. Since the model should permit not only the representation of known aspects of reality, but also the derivation of information from the existing representation, the design of the model is constrained so as to afford these capabilities. The tessellation of space by the network of simplest geometry, the simplicial network, is proposed as a solution. The known aspects of the reality can be embedded in the simplicial network without degrading their quality. The model provides finite spatial units useful for the representation of objects. Relationships between objects can also be expressed through components of these spatial units which at the same time facilitate various computations and the derivation of information implicitly available in the model. Since the simplicial network is based on concepts in geoinformation science and in mathematics, its design can be generalized for n-dimensions. The networks of different dimension are said to be compatible, which enables the incorporation of a simplicial network of a lower dimension into another simplicial network of a higher dimension.The complexity of the 3D model fulfilling the requirements listed calls for a suitable construction method. The thesis presents a simple way to construct the model. The raster technique is used for the formation of the simplicial network embedding the representation of the known aspects of reality as constraints. The prototype implementation in a software package, ISNAP, demonstrates the simplicial network's construction and use. The simplicial network can facilitate spatial and non spatial queries, computations, and 2D and 3D visualizations. The experimental tests using different kinds of data sets show that the simplicial network can be used to represent real world objects in different dimensionalities. Operations traditionally requiring different systems and spatial models can be carried out in one system using one model as a basis. This possibility makes the GIS more powerful and easy to use

Dynamic Vector and Raster Integrated Data Model Based on Code-Points

With the rapid development of remote sensing technology, the integration of raster data and vector data becomes more and more important. Raster data rnodels are used in tessellation spaces and vector data models are used in discrete spaces respectively. The relationships between tessellation space and discrete space have to be established for integrated data models. The minimum cells where both raster and vector data could be processed have to be defined. As it is very easy to establish relationships between vector points and corresponding raster cells, we defined those raster cells as Code-Points, the minimum cells where both raster and vector data could be processed. All vector elements such as lines, faces and bodies are composed directly or indirectly of Code-Points. This can be done by using interpolation algorithms to Code-Points in real-time. We have developed an integrated data model based on above procedures. In addition, we have developed a geometric primitive library for 3-Dimensional objects in order to improve the processing speed. This library could be hardware realized as a graphic accelerator card. If the conversion between vector and raster could be done in real time, the integrated data model could be used for operational integration of remote sensing and GIS. ? Springer-Verlag 2002.EI

Trends in 3D GIS Development

Currently, a variety of software is capable of handling a wide range of spatial problems, beginning with approaches for describing spatial objects to quite complex analysis and 3D visualisation. However, an increasing number of applications need more advanced tools for representing and analysing the 3D world. Among all types of systems dealing with spatial information, GIS has proven to be the most sophisticated system that operates with the largest scope of objects (spatial and semantic), relationships and provide means to analyse them. However, what is the status of 3D GIS? It is the aim of this paper to find the answer by analysing both available software and efforts of researchers. An overview of several software packages and 3D case studies performed in Oracle and Microstation is given to provide knowledge about the 3D functionality offered by commercial systems. The most significant achievements in the 3D research area concerning key issues of 3D GIS, i.e. 3D structuring and 3D topology are summarized to portray the current research status. At the end, some of the issues and problems involved in developing such a system are presented and recommendations on directions for further research are made. The scope of the paper is limited to 3D GIS systems and research in vector domain. Problems of subsurface applications are excluded as well

INTEGRATION OF GEO-SENSOR FEEDS AND EVENT CONSUMER SERVICES FOR REAL-TIME REPRESENTATION OF IOT NODES

More and more devices are starting to be connected to the Internet every day. Internet-of-Things (IoT) is known as an architecture where online devices have the ability to communicate and interact with each other in real-time. On the other hand, with the development of IoT related technologies information about devices (i.e. Things) can be acquired in real-time by the humans. The implementation of IoT related technologies requires new approaches to be investigated for novel system architectures. These architectures need to have 3 main abilities. The first one is the ability is to store and query information coming from millions of devices in real-time. The second one is the ability to interact with large number of devices seamlessly regardless of their hardware and their software platforms. The final one is the ability to visualise and present information coming from millions of sensors in real time. The paper provides an architectural approach and implementation tests for storage, exposition and presentation of large amounts of real-time geo-information coming from multiple IoT nodes (and sensors)