Sylvie Servigne

A Methodology for Spatial Consistency Improvement of Geographic Databases

In any information system the reliability of any results of queries, analysis or reasoning, depends on data quality (positional accuracy, consistency and so on). In some cases, answers cannot be obtained due to a lack of information, whereas in other cases answers are wrong or not complete because of inconsistent data. In geographical information systems (GIS), data quality management has to handle the spatial features of objects, which brings specific problems. The goal of this paper is to describe a methodology for spatial consistency improvement of geographical data sets in vector format. It is based on errors survey and classification. Three kinds of errors are identified which lead to three kinds of consistency, namely structural consistency, geometric consistency and topo-semantic consistency. Each of them needs specific checking and correcting processes. All these processes are integrated in a general framework that is presented in this paper. An application of this framework to the Lyon Urban Community GIS (the SUR) is currently conducted; first results are presented.

First specifications of a telegeomonitoring system for the transportation of hazardous materials

Abstract The present work gives general specifications for a monitoring system for the transportation of hazardous materials. The initial structure of the spatial decision support system integrates a range of databases on an interoperable environment. The data integration task illustrates the complex nature of the hazardous materials monitoring system. Three important components of the project, strongly linked to the spatial information system technology, are: (1) operators of graph traversal that is schematized by an object software component; (2) operators of communications proposing the basics of communication between trucks using a global positioning system (GPS) and the supervision system; and (3) the opening of services put at the disposal of the various professional users: public and private operators, etc. The advent of Internet technology democratizes communication and accesses possibilities to services given by the monitoring system. However, for professional utilization an adequate technical infrastructure is proposed. The dynamic knowledge integration in the system of supervision of hazardous materials transportation ensures that spatio-temporal data, real-time constraints, and history of events are taken into account.

Soft Real-Time GIS for Disaster Monitoring

The goal of this paper is to underline the importance of real-time systems for managing information during the phase of disaster monitoring. We stress the importance of soft real-time GIS, and we present a list of barriers to overcome in order to get this kind of system. Among the barriers, we present a solution for real-time indexing of spatio-temporal data based on a data structure named PO-Tree.

First specifications of an information system for urban soundscape

Sounds are very important in our daily life with a twofold attitude for any citizen. On the one hand, music sounds are considered to enhance the quality of life, but on the other hand, traffic noise deteriorates the quality of life. Due to those contradictory characteristics, the new concept of soundscape tries to combine both positive and negative aspects of the auditory environment. Presently, and more and more in the future, any urban planning activities must try to diminish noise levels everywhere in the cities and also outside, for instance at the vicinity of airports. Local authorities daily receive complaints regarding noise, but they generally come from very quiet precincts, and practically never from very noisy zones such as along busy highways. So, it is very important to provide the urban decision-makers with an objective tool to compare not only noise levels but also soundscape, and to simulate the auditory impacts of any new urban developments. The goal of this paper is to give the first elements of the design of an information system dedicated to auditory information for cities. The paper describes the importance of the urban soundscape, the structure of the information system and some elements for the visualization of sounds.

A primer on TeleGeoProcessing and TeleGeoMonitoring

Abstract The goal of this paper is to define the potential and the characteristics of TeleGeoProcessing and TeleGeoMonitoring. TeleGeoProcessing, as child of geographical information systems and telecommunications, can be considered as a new discipline characterized by spatial database, cartography on demand, the exchange of information between different sites by any kind of telecommunication systems, and on-line spatial data analysis. TeleGeoMonitoring can be seen as an extension of TeleGeoProcessing by the use of positioning systems (global positioning systems [GPS] or GPS-like), real-time databases and real-time group decision-making systems.

Representation and visualization of urban fabric through historical documents

Documents serve an important role in understanding change in urban fabric. The available multidimensional (spatial, temporal and thematic) information in these documents narrate not only the various features of the elements of the urban fabric but also notifies their changes during time. CityGML standard is used to spatially and temporally represent the city objects. But it misses features to represent city lifecycle and its linked documents. The first part has been addressed recently. In this article, we propose an extension to CityGML standard to integrate city objects and relevant associated documents. Proposing a solution based on standards permits data interoperability. We also briefly describe how these documents are visualized in our current 3D urban environment prototype built over CityGML.

The Po-tree: a Real-time Spatiotemporal Data Indexing Structure

This document describes the Po-tree, a new indexing structure for spatiotemporal databases with real-time constraints. Natural risks management and other system can use arrays of spatially referenced sensors, each of them sending their measurements to a central database. Our solution tries to facilitate the indexing of these data, while favoring the newer ones. It does so by combining two sub-structures for the spatial and temporal components. While Mobility is not yet supported, evolutions of the structures shall be able to deal with it.

Updating urban database with aerial photographs: A common structuring methodology

Abstract Updated geographical information systems and especially cadastre 2 are difficult to obtain in real time. The goal of our work is to use aerial photos to automatically update a cadastre database. The first problem concerns the difficulties of managing aerial photographs in a raster format. This leads us to propose a methodology that permits one to manipulate in the same way, raster and vector data. That implies the same process (based on Delaunay triangulation) and the same model (including topology). Aerial photoprocessing and cadastre handling provide information about objects and relations between them. They are described in the structural map that will be enriched with derived spatial relations. This global common description for cadastre and photographs is the central point for comparison and updating.

Managing Sensor Data Uncertainty: A Data Quality Approach

With an increasingly technological improvement, sensors infrastructure actually supports many current and promising environmental applications. Environmental Monitoring Systems built on such sensors removes geographical, temporal and other restraints while increasing both the coverage and the quality of real world understanding. However, a main issue for such applications is the uncertainty of data coming from sensors, which may impact experts’ decisions. In this paper, the authors address this problem with an approach dedicated to provide environmental monitoring applications and users with data quality information.

Visual access to city websites: A challenge for PDA's GUI

At the inception of the Internet, the websites were only textual. Now, with the graphic possibilities, more and more websites integrate visual aspects, essentially to access and to visualize information. The goal of this paper is to examine the use of some visual techniques in city websites. More particularly, we will examine the metaphor of virtual cities, hypermaps and geography-based accesses, news magazines, etc. In the last part of this paper, we will examine the implications of using those metaphors for small screens, and overall for Graphic User Interfaces (GUI) of Personal Digital Assistant (PDA). We will essentially argue that as the syntactic transformations, i.e., the syntactic adaptations are one face of the problem, the semantic adaptation, i.e., the transformation or the adaptation of the metaphors, is a very challenging issue.