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International Workshop on Advanced Research in Geographic Information Systems Monte Verità, Ascona, Switzerland February 28 – March 4, 1994 Proceedings
In this paper we examine the basic issues related to the design of development environments for applications in the field of land information analysis (land planning, risk assessment, urban design, pollution control, and so on). In particular, we discuss the approach we believe correct in the development environment design. Moreover, we point out that the development environments should provide the...
Human beings use hierarchies extensively to simplify their conceptual models of reality and to perform reasoning more efficiently. Hierarchical structures are conceptually imposed on space and allow better performance of complex tasks in very large contexts. To understand how spatial hierarchies are formed and used is one of the most important questions in spatial reasoning research. In this project,...
The basic concept for processing spatial joins consists of two steps: First, the spatial join is performed on the minimum bounding rectangles of the objects by using a spatial access method. This step provides a set of candidates which consists of answers (hits) and non-answers (false hits). In the second step, the exact geometry of the candidates is transferred from secondary storage into main memory...
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...
DOMUS is a project of the Computer Science Department of UNICAMP, Brazil, for the development of a GIS for environmental control applications using an object oriented database. This project involves experts from different areas, both in Computer Science and in Geosciences. This paper describes the results already obtained in this project, as well as the ongoing efforts to extend available GIS technology,...
One challenge in spatial data modelling is related to multiple representation of geographic objects. While often associated with cartographic change of scale and generalization, it applies in fact to a wider range of data analysis situations. We discuss multiple representation issues from a data modelling point of view, with emphasis on hierarchical structures inherent to multiple resolution levels...
There have been many interpolation methods developed over the years, each with their own problems. One of the biggest limitations in many applications is the non-correspondence of the surface with the objects used to support it — usually a set of arbitrarily distributed data points. This is due to the metric methods used to define both the zone of influence of a data point and the set of data points...
We propose a new model for representing a hypersurface describing a scalar field in any dimension at different levels of detail. The model is based on a decomposition of the domain into a hierarchy of simplicial complexes. We present a data structure for encoding such model as well as an algorithm for building a multiresolution representation of a hypersurface based on a decreasing sequence of tolerance...
Global climatological data are often evaluated in grids with perpendicular boundaries in a cylinder projection of the longitude and latitude circles of the earth. Typical datasets contain 106 to 108 values. Each dataset is organized in a different grid, according to the authors's preferences. When calculating the global radiation over the ocean, for example, it is essential that cloud data from at...
The report describes software developed at the Institute for Nuclear Safety (Moscow) for the analysis of off-site consequences connected with nuclear technology. A number of computer environments developed and widely used are presented. A general description of the Central Data Bank on Chernobyl accident is presented. Attributive information has been accumulated for about 10,000 populated areas...
This paper studies efficient path computation methods that can be applied on digital elevation models represented by a triangulation (called polyhedral terrains). The quality of the path is measured in the following aspects: Euclidean length, lying below a given height Z, avoiding large slope regions, and total height difference. Known techniques that can be used are reviewed, and it is shown how...
This paper addresses the topic of semi-automatic object extraction for GIS data capture. It includes novel algorithms and conceptual strategies, together with performed experiments, encountered problems and adopted solutions. In particular, we present an algorithm and obtained results for semi-automatic extraction of road networks from SPOT imagery using wavelet-transformed images and cost functions...
This paper describes an interdisciplinary research project aimed at developing a prototype system for representing spatial data. The project involves researchers and teachers in urban design, computer aided design and photogrammetry. The paper first highlights the spectrum of information used in urban design contexts that guided the approach we adopted in developing the prototype system. We next describe...
A description and discussion of the basis for coupling knowledge-based systems and Geographic Information Systems is presented using a process-based model of vegetation change as an example. A frame structure is used for the representation of knowledge and attributes of spatial data, including measures of uncertainty in the data and results. In this prototype we include representation of the other...
While recent hardware and software developments made Geographic Information Systems (GIS) systems widely available there are still many problems to be solved. Partially in contrast to the mainstream in GIS research, the most important technical issues of real-world projects point to processes which support an efficient, economic but long living ‘data life cycle’, namely: 1. Data capturing; 2. Continuous...
Traditional approaches to spatial and geometrical data management are based on mappings of spatial objects to individual disk pages. However, modern operating-system and hardware technologies allow variable-sized and large I/O operations to be handled almost as efficiently as fixed-sized individual block operations, and, based on this technology, our DASDBS Storage Manager implements a nested-relational...
In this paper all major issues related to definition, design and implementation of a prototype of the geographical information system CARTECH are presented and discussed. The prototype proposes solutions for the most important requirements for geographical information systems (GIS). Namely, the double nature (spatial and descriptive) of geographical data, the fact that querying geographical information...
Spatial Data Management and Spatial Data Processing often requires technology of many different computer science disciplines like Data Management, Computational Geometry, Statistics, and Data Visualisation. Todays GIS try to integrate this technology into one single, large, software package. We propose a new flexible solution for keeping the specialised software packages independent and autonomous...
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