N. Van De Weghe - Academia.edu (original) (raw)
Papers by N. Van De Weghe
1. Digital tracking technologies have considerably increased the amount and quality of animal tra... more 1. Digital tracking technologies have considerably increased the amount and quality of animal trajectories, enabling the study of habitat use and habitat selection at a fine spatial and temporal scale. However, current approaches do not yet explicitly account for a key aspect of habitat use, namely the sequential variation in the use of different habitat features. 2. To overcome this limitation, we propose a tree-based approach that makes use of sequence analysis methods, derived from molecular biology, to explore and identify ecologically relevant sequential patterns in habitat use by animals. We applied this approach to ecological data consisting of simulated and real trajectories from a roe deer population (Capreolus capreolus), expressed as ordered sequences of habitat use. 3. We show that our approach effectively captured spatio-temporal patterns of sequential habitat use by roe deer. In our case study, individual sequences were clustered according to the sequential use of the elevation gradient (first order) and of open/closed habitats (second order). We provided evidence for several behavioural processes , such as migration and daily alternating habitat use. Some unexpected patterns, such as homogeneous sequences of use of open habitat, could also be identified. 4. Our findings advocate the importance of dealing with the sequential nature of movement data. Approaches based on sequence analysis methods are particularly useful and effective since they allow exploring temporal patterns of habitat use in a synthetic and visually captive manner. The proposed approach represents a useful and effective way to classify individual movement behaviour across populations and species. Ultimately, this method can be applied to explore the temporal scale of ecological processes based on movement.
GeoPlatform, 2008
... Record Details. Record ID, 436444. Record Type, journalArticle. Author, Matthias Delafontaine... more ... Record Details. Record ID, 436444. Record Type, journalArticle. Author, Matthias Delafontaine [802000077838] - Ghent University Matthias.Delafontaine@UGent.be; G NOLF; Nico Van de Weghe [801001472437] - Ghent University Nico.VandeWeghe@UGent.be; ...
In the past two decades urban time policies have been proposed and implemented in many European c... more In the past two decades urban time policies have been proposed and implemented in many European cities as a complement to traditional spatial planning methods. Such policies seek to provide an answer to the growing number of people facing time problems as a result of an erosion of collective time rhythms and a desynchronisation of different time structures of urban life. Particular emphasis is being placed on the reconciliation of opening hours of public service facilities with the travel and activity patterns of citizens in order to increase individual accessibility to urban services. In spite of the increasing relevance of time policies, only limited quantitative research has been conducted about the relationships between opening hours and accessibility. This paper seeks to extend this line of inquiry by exploring if and to what extent the accessibility of public facilities can be ameliorated by redesigning the timetables of service delivery. A method is proposed to optimise the temporal regime of public service delivery in terms of accessibility. The method is illustrated in a case study of accessibility of government offices within the city of Ghent (Belgium). Our findings suggest that by rescheduling the opening hours of public service facilities individual accessibility to service delivery can be improved significantly. Our study may support urban service deliverers, policymakers and urban planners in assessing timetables for a better 'accessible' service provision.
A lot of disciplines (e.g. archaeology) have to process imprecise temporal information. There are... more A lot of disciplines (e.g. archaeology) have to process imprecise temporal information. There are different possibilities to handle this kind of information, amongst them e.g. fuzzy set theory and rough set theory. In this paper, due to its capability in the context of many data acquisition applications, the focus has been set on rough set theory. To illustrate temporal information, an interval is often visualised by means of a one-dimensional segment in a one- dimensional space. An alternative representation of time intervals is called the Triangular Model (TM) by which a time interval is represented by a point in a two-dimensional space. In this paper, rough set theory is applied into TM, which gets extended to the Rough Triangular Model (RTM). In RTM, Rough Time Intervals (RTI) and their mutual relations can be visualised diagrammatically, which offers opportunities to visualise and analyse imprecise temporal information. Aerial photos, taken during World War , containing impreci...
Expert Systems with Applications, 2011
Note to users: The section "Articles in Press" contains peer reviewed accepted articles... more Note to users: The section "Articles in Press" contains peer reviewed accepted articles to be published in this journal. When the final article is assigned to an issue of the journal, the "Article in Press" version will be removed from this section and will appear in the associated ...
Oriceedubgs vab de …, 2006
... Record Details. Record ID, 363290. Record Type, conference. Author, Matthias Delafontaine [80... more ... Record Details. Record ID, 363290. Record Type, conference. Author, Matthias Delafontaine [802000077838] - Ghent University Matthias.Delafontaine@UGent.be; Nico Van de Weghe [801001472437] - Ghent University Nico.VandeWeghe@UGent.be; ...
While many studies have concentrated on the effects of the spatial distribution of services on in... more While many studies have concentrated on the effects of the spatial distribution of services on individual accessibility, only little is known about the ways in which equity of individual accessibility is affected by the temporal organisation of service delivery. This paper seeks to deepen our understanding about the relationship between accessibility, equity and the opening hours of public service facilities on the basis of space-time accessibility measures. Three approaches based on different equity principles are presented to schedule the opening hours of public service facilities: a utilitarian, an egalitarian and a distributive approach. A case study of public libraries in Ghent (Belgium) demonstrates the relevance of these approaches for amending the opening hours of public services to control the equity of accessibility levels across individuals.
Information Visualization, 2012
Time intervals are conventionally represented as linear segments in a one-dimensional space. An a... more Time intervals are conventionally represented as linear segments in a one-dimensional space. An alternative representation of time intervals is the triangular model (TM), which represents time intervals as points in a two-dimensional space. In this paper, the use of TM in visualising and analysing time intervals is investigated. Not only does this model offer a compact visualisation of the distribution of intervals, it also supports an innovative temporal query mechanism that relies on geometries in the two-dimensional space. This query mechanism has the potential to simplify queries that are difficult to specify using traditional linear temporal query devices. Moreover, a software prototype that implements TM in a geographical information system (GIS) is introduced. This prototype has been applied in a real scenario to analyse time intervals that were detected by a Bluetooth tracking system. This application shows that TM has the potential to support a traditional GIS to analyse interval-based geographical data.
Information Sciences, 2011
It is widely held that people tend to use qualitative rather than quantitative phrases when raisi... more It is widely held that people tend to use qualitative rather than quantitative phrases when raising or answering questions about moving objects. Queries about whether an object is moving towards or away from another object or whether objects are getting closer to each other or further away from each other, require qualitative responses. This characteristic should be reflected in a calculus to be used to describe and reason about continuously moving objects. In this paper, we present a qualitative trajectory calculus of relations between two disjoint moving objects, whose movement is constrained by a network. The proposed calculus (QTC N ) is formally introduced and illustrated. Particular attention is placed on how to infer additional knowledge from QTC N relations by means of composition tables and the transformation of QTC N relations into relations defined by the Relative Trajectory Calculus on Networks (RTC N ).
International Journal of Geographical Information Science, 2009
As positional error is a major issue in the assessment of spatial data quality, its propagation h... more As positional error is a major issue in the assessment of spatial data quality, its propagation has been studied widely in map overlaying. However, few studies deal with a manifest consequence of positional error in map overlaying, namely sliver polygons. Sliver polygons are ...
Conference proceeding …, 2009
1CartoGIS Cluster, Dept. of Geography, Ghent University, Belgium 2 Dept. of Archaeology and Ancie... more 1CartoGIS Cluster, Dept. of Geography, Ghent University, Belgium 2 Dept. of Archaeology and Ancient History of Europe, Ghent University, Belgium 3 Dept. of Telecommunications and Information Processing, Ghent University, Belgium ... E-mail: {Yi.Qiang, Katrin.Asmussen, Matthias. ...
Trends and Future Directions, 2012
... 4. A Qualitative Trajectory Calculus to Reason about Moving Point Objects (pages 147-167).Mat... more ... 4. A Qualitative Trajectory Calculus to Reason about Moving Point Objects (pages 147-167).Matthias Delafontaine (Ghent University ... Generation over Temporal Interval Algebra (pages 273-283). Debasis Mitra (Florida Institute of Technology, USA), Florent Launay (Florida ...
Applied Geography, 2012
The use of Bluetooth technology as a technique to collect data about the movement of individuals ... more The use of Bluetooth technology as a technique to collect data about the movement of individuals is increasingly gaining attention. This paper explores the potential of sequence alignment methods to analyse data obtained from Bluetooth tracking. To this end, an empirical case study is elaborated which applies sequence alignment methods to examine the behavioural patterns of visitors tracked by Bluetooth at a major trade fair in Belgium. The results and findings underline the validity of Bluetooth tracking to collect data from visitors at mass events, as well as the ability of sequence alignment methods to extract insightful information from sequences within such data.
International Journal of Geographical Information Science, 2011
... 518571 Matthias Delafontaine a * , Tijs Neutens a & Nico Van de Weghe a Available... more ... 518571 Matthias Delafontaine a * , Tijs Neutens a & Nico Van de Weghe a Available online: 24 Aug 2011. ... Urban Geography , 29: 556–580. [CrossRef], [Web of Science ®] View all references).Hendricks et al. (200313. Hendricks, MD, Egenhofer, MJ and Hornsby, K. 2003. ...
Every event has an extent in time, which is usually described by crisp time intervals. However, u... more Every event has an extent in time, which is usually described by crisp time intervals. However, under some circumstances, temporal extents of events are imperfect, and therefore cannot be adequately modelled by crisp time intervals. Rough sets and fuzzy sets are two frequently used tools for representing imperfect temporal information. In this paper, we apply a two-dimensional representation of crisp time intervals, which is called the Triangular Model (TM), to investigate rough time intervals (RTIs) and fuzzy time intervals (FTIs). With this model, RTIs and FTIs, as well as their temporal relations, can be represented as graphics (i.e. discrete geometries or continuous fields) in a two-dimensional time space. Compared to the traditional linear representation of time intervals, we found that TM provides a more compact and clearer representation of imperfect time intervals and relations. Moreover, temporal queries of imperfect intervals can be graphically addressed in TM, which is closer to human intuition than mathematical expressions. As human minds are more efficient in perceiving and processing graphic representations than numerical representations, we believe TM can be applied as a valuable assistant tool for analysing and reasoning about imperfect time intervals.
Applied Geography, 2012
ABSTRACT In this paper, proximity-based Bluetooth tracking is postulated as an efficient and effe... more ABSTRACT In this paper, proximity-based Bluetooth tracking is postulated as an efficient and effective methodology for analysing the complex spatiotemporal dynamics of visitor movements at mass events. A case study of the Ghent Festivities event (1.5 million visitors over 10 days) is described in detail and preliminary results are shown to give an indication of the added value of the methodology for stakeholders of the event. By covering 22 locations in the study area with Bluetooth scanners, we were able to extract 152,487 trajectories generated by 80,828 detected visitors. Apart from generating clear statistics such as visitor counts, the share of returning visitors, and visitor flow maps, the analyses also reveal the complex nature of this event by hinting at the existence of several mutually different visitor profiles. We conclude by arguing why Bluetooth tracking offers significant advantages for tracking mass event visitors with respect to other and more prominent technologies, and outline some of its remaining deficiencies.
International Journal of Geographical Information Science, 2012
This article introduces a novel geographical information system toolkit for measuring and mapping... more This article introduces a novel geographical information system toolkit for measuring and mapping the accessibility of individuals to services. The toolkit contributes to earlier implementations by combining aspects of both place-based and person-based accessibility measures. To this end, place-based accessibility measures are derived from a person-based framework by considering space–time prisms that are centred at service facilities rather than individual anchor points. The implementation is also innovative by explicitly accounting for the opening hours of service delivery in its accessibility measurement. In addition, the toolkit is aimed to be user-friendly and to generate insightful and comprehensible results for non-technically oriented users, which is illustrated in a brief case study about library accessibility in Ghent (Belgium).
Moving objects are commonly handled using quantitative methods and information. However, in many ... more Moving objects are commonly handled using quantitative methods and information. However, in many cases, qualitative information can be more efficient and more meaningful than quantitative information. A lot of research has been done in generating, indexing, modelling and querying network-based moving objects, but little work has been done in building a calculus of relations between these objects in a qualitative way. In this paper, we introduce a formal definition of how to represent and reason about the relative trajectories of pairs of objects moving along a network.
Lecture Notes in Computer Science, 2005
MA Rodríguez et al. (Eds.): GeoS 2005, LNCS 3799, pp. 6076, 2005. © Springer-Verlag Berlin Heide... more MA Rodríguez et al. (Eds.): GeoS 2005, LNCS 3799, pp. 6076, 2005. © Springer-Verlag Berlin Heidelberg 2005 ... A Qualitative Trajectory Calculus and the Composition ... Nico Van de Weghe1, Bart Kuijpers2, Peter Bogaert1, and Philippe De Maeyer1
Research has previously been conducted in the area of generating, indexing, modelling and queryin... more Research has previously been conducted in the area of generating, indexing, modelling and querying network-based moving objects. However, little work has been done in building a calculus of relations between disconnected network-based mobile objects. In this paper an approach to qualitatively representing and reasoning about trajectories of pairs of objects moving along a road network is presented. We call this approach the "Qualitative Trajectory Calculus along a road Network" (QTCN). We start from the assumption that two objects are moving continuously towards each other or away from each other, and consider how to describe their joint trajectories. Since the distance between two objects is measured along the shortest path, specific attention will be given to changes in shortest path, and more specifically changes in direction of the velocity vector of an object with reference to the shortest path between two objects. A conceptual neighbourhood diagram is presented, that forms the basis for a representation of a conceptual animation.
1. Digital tracking technologies have considerably increased the amount and quality of animal tra... more 1. Digital tracking technologies have considerably increased the amount and quality of animal trajectories, enabling the study of habitat use and habitat selection at a fine spatial and temporal scale. However, current approaches do not yet explicitly account for a key aspect of habitat use, namely the sequential variation in the use of different habitat features. 2. To overcome this limitation, we propose a tree-based approach that makes use of sequence analysis methods, derived from molecular biology, to explore and identify ecologically relevant sequential patterns in habitat use by animals. We applied this approach to ecological data consisting of simulated and real trajectories from a roe deer population (Capreolus capreolus), expressed as ordered sequences of habitat use. 3. We show that our approach effectively captured spatio-temporal patterns of sequential habitat use by roe deer. In our case study, individual sequences were clustered according to the sequential use of the elevation gradient (first order) and of open/closed habitats (second order). We provided evidence for several behavioural processes , such as migration and daily alternating habitat use. Some unexpected patterns, such as homogeneous sequences of use of open habitat, could also be identified. 4. Our findings advocate the importance of dealing with the sequential nature of movement data. Approaches based on sequence analysis methods are particularly useful and effective since they allow exploring temporal patterns of habitat use in a synthetic and visually captive manner. The proposed approach represents a useful and effective way to classify individual movement behaviour across populations and species. Ultimately, this method can be applied to explore the temporal scale of ecological processes based on movement.
GeoPlatform, 2008
... Record Details. Record ID, 436444. Record Type, journalArticle. Author, Matthias Delafontaine... more ... Record Details. Record ID, 436444. Record Type, journalArticle. Author, Matthias Delafontaine [802000077838] - Ghent University Matthias.Delafontaine@UGent.be; G NOLF; Nico Van de Weghe [801001472437] - Ghent University Nico.VandeWeghe@UGent.be; ...
In the past two decades urban time policies have been proposed and implemented in many European c... more In the past two decades urban time policies have been proposed and implemented in many European cities as a complement to traditional spatial planning methods. Such policies seek to provide an answer to the growing number of people facing time problems as a result of an erosion of collective time rhythms and a desynchronisation of different time structures of urban life. Particular emphasis is being placed on the reconciliation of opening hours of public service facilities with the travel and activity patterns of citizens in order to increase individual accessibility to urban services. In spite of the increasing relevance of time policies, only limited quantitative research has been conducted about the relationships between opening hours and accessibility. This paper seeks to extend this line of inquiry by exploring if and to what extent the accessibility of public facilities can be ameliorated by redesigning the timetables of service delivery. A method is proposed to optimise the temporal regime of public service delivery in terms of accessibility. The method is illustrated in a case study of accessibility of government offices within the city of Ghent (Belgium). Our findings suggest that by rescheduling the opening hours of public service facilities individual accessibility to service delivery can be improved significantly. Our study may support urban service deliverers, policymakers and urban planners in assessing timetables for a better 'accessible' service provision.
A lot of disciplines (e.g. archaeology) have to process imprecise temporal information. There are... more A lot of disciplines (e.g. archaeology) have to process imprecise temporal information. There are different possibilities to handle this kind of information, amongst them e.g. fuzzy set theory and rough set theory. In this paper, due to its capability in the context of many data acquisition applications, the focus has been set on rough set theory. To illustrate temporal information, an interval is often visualised by means of a one-dimensional segment in a one- dimensional space. An alternative representation of time intervals is called the Triangular Model (TM) by which a time interval is represented by a point in a two-dimensional space. In this paper, rough set theory is applied into TM, which gets extended to the Rough Triangular Model (RTM). In RTM, Rough Time Intervals (RTI) and their mutual relations can be visualised diagrammatically, which offers opportunities to visualise and analyse imprecise temporal information. Aerial photos, taken during World War , containing impreci...
Expert Systems with Applications, 2011
Note to users: The section "Articles in Press" contains peer reviewed accepted articles... more Note to users: The section "Articles in Press" contains peer reviewed accepted articles to be published in this journal. When the final article is assigned to an issue of the journal, the "Article in Press" version will be removed from this section and will appear in the associated ...
Oriceedubgs vab de …, 2006
... Record Details. Record ID, 363290. Record Type, conference. Author, Matthias Delafontaine [80... more ... Record Details. Record ID, 363290. Record Type, conference. Author, Matthias Delafontaine [802000077838] - Ghent University Matthias.Delafontaine@UGent.be; Nico Van de Weghe [801001472437] - Ghent University Nico.VandeWeghe@UGent.be; ...
While many studies have concentrated on the effects of the spatial distribution of services on in... more While many studies have concentrated on the effects of the spatial distribution of services on individual accessibility, only little is known about the ways in which equity of individual accessibility is affected by the temporal organisation of service delivery. This paper seeks to deepen our understanding about the relationship between accessibility, equity and the opening hours of public service facilities on the basis of space-time accessibility measures. Three approaches based on different equity principles are presented to schedule the opening hours of public service facilities: a utilitarian, an egalitarian and a distributive approach. A case study of public libraries in Ghent (Belgium) demonstrates the relevance of these approaches for amending the opening hours of public services to control the equity of accessibility levels across individuals.
Information Visualization, 2012
Time intervals are conventionally represented as linear segments in a one-dimensional space. An a... more Time intervals are conventionally represented as linear segments in a one-dimensional space. An alternative representation of time intervals is the triangular model (TM), which represents time intervals as points in a two-dimensional space. In this paper, the use of TM in visualising and analysing time intervals is investigated. Not only does this model offer a compact visualisation of the distribution of intervals, it also supports an innovative temporal query mechanism that relies on geometries in the two-dimensional space. This query mechanism has the potential to simplify queries that are difficult to specify using traditional linear temporal query devices. Moreover, a software prototype that implements TM in a geographical information system (GIS) is introduced. This prototype has been applied in a real scenario to analyse time intervals that were detected by a Bluetooth tracking system. This application shows that TM has the potential to support a traditional GIS to analyse interval-based geographical data.
Information Sciences, 2011
It is widely held that people tend to use qualitative rather than quantitative phrases when raisi... more It is widely held that people tend to use qualitative rather than quantitative phrases when raising or answering questions about moving objects. Queries about whether an object is moving towards or away from another object or whether objects are getting closer to each other or further away from each other, require qualitative responses. This characteristic should be reflected in a calculus to be used to describe and reason about continuously moving objects. In this paper, we present a qualitative trajectory calculus of relations between two disjoint moving objects, whose movement is constrained by a network. The proposed calculus (QTC N ) is formally introduced and illustrated. Particular attention is placed on how to infer additional knowledge from QTC N relations by means of composition tables and the transformation of QTC N relations into relations defined by the Relative Trajectory Calculus on Networks (RTC N ).
International Journal of Geographical Information Science, 2009
As positional error is a major issue in the assessment of spatial data quality, its propagation h... more As positional error is a major issue in the assessment of spatial data quality, its propagation has been studied widely in map overlaying. However, few studies deal with a manifest consequence of positional error in map overlaying, namely sliver polygons. Sliver polygons are ...
Conference proceeding …, 2009
1CartoGIS Cluster, Dept. of Geography, Ghent University, Belgium 2 Dept. of Archaeology and Ancie... more 1CartoGIS Cluster, Dept. of Geography, Ghent University, Belgium 2 Dept. of Archaeology and Ancient History of Europe, Ghent University, Belgium 3 Dept. of Telecommunications and Information Processing, Ghent University, Belgium ... E-mail: {Yi.Qiang, Katrin.Asmussen, Matthias. ...
Trends and Future Directions, 2012
... 4. A Qualitative Trajectory Calculus to Reason about Moving Point Objects (pages 147-167).Mat... more ... 4. A Qualitative Trajectory Calculus to Reason about Moving Point Objects (pages 147-167).Matthias Delafontaine (Ghent University ... Generation over Temporal Interval Algebra (pages 273-283). Debasis Mitra (Florida Institute of Technology, USA), Florent Launay (Florida ...
Applied Geography, 2012
The use of Bluetooth technology as a technique to collect data about the movement of individuals ... more The use of Bluetooth technology as a technique to collect data about the movement of individuals is increasingly gaining attention. This paper explores the potential of sequence alignment methods to analyse data obtained from Bluetooth tracking. To this end, an empirical case study is elaborated which applies sequence alignment methods to examine the behavioural patterns of visitors tracked by Bluetooth at a major trade fair in Belgium. The results and findings underline the validity of Bluetooth tracking to collect data from visitors at mass events, as well as the ability of sequence alignment methods to extract insightful information from sequences within such data.
International Journal of Geographical Information Science, 2011
... 518571 Matthias Delafontaine a * , Tijs Neutens a & Nico Van de Weghe a Available... more ... 518571 Matthias Delafontaine a * , Tijs Neutens a & Nico Van de Weghe a Available online: 24 Aug 2011. ... Urban Geography , 29: 556–580. [CrossRef], [Web of Science ®] View all references).Hendricks et al. (200313. Hendricks, MD, Egenhofer, MJ and Hornsby, K. 2003. ...
Every event has an extent in time, which is usually described by crisp time intervals. However, u... more Every event has an extent in time, which is usually described by crisp time intervals. However, under some circumstances, temporal extents of events are imperfect, and therefore cannot be adequately modelled by crisp time intervals. Rough sets and fuzzy sets are two frequently used tools for representing imperfect temporal information. In this paper, we apply a two-dimensional representation of crisp time intervals, which is called the Triangular Model (TM), to investigate rough time intervals (RTIs) and fuzzy time intervals (FTIs). With this model, RTIs and FTIs, as well as their temporal relations, can be represented as graphics (i.e. discrete geometries or continuous fields) in a two-dimensional time space. Compared to the traditional linear representation of time intervals, we found that TM provides a more compact and clearer representation of imperfect time intervals and relations. Moreover, temporal queries of imperfect intervals can be graphically addressed in TM, which is closer to human intuition than mathematical expressions. As human minds are more efficient in perceiving and processing graphic representations than numerical representations, we believe TM can be applied as a valuable assistant tool for analysing and reasoning about imperfect time intervals.
Applied Geography, 2012
ABSTRACT In this paper, proximity-based Bluetooth tracking is postulated as an efficient and effe... more ABSTRACT In this paper, proximity-based Bluetooth tracking is postulated as an efficient and effective methodology for analysing the complex spatiotemporal dynamics of visitor movements at mass events. A case study of the Ghent Festivities event (1.5 million visitors over 10 days) is described in detail and preliminary results are shown to give an indication of the added value of the methodology for stakeholders of the event. By covering 22 locations in the study area with Bluetooth scanners, we were able to extract 152,487 trajectories generated by 80,828 detected visitors. Apart from generating clear statistics such as visitor counts, the share of returning visitors, and visitor flow maps, the analyses also reveal the complex nature of this event by hinting at the existence of several mutually different visitor profiles. We conclude by arguing why Bluetooth tracking offers significant advantages for tracking mass event visitors with respect to other and more prominent technologies, and outline some of its remaining deficiencies.
International Journal of Geographical Information Science, 2012
This article introduces a novel geographical information system toolkit for measuring and mapping... more This article introduces a novel geographical information system toolkit for measuring and mapping the accessibility of individuals to services. The toolkit contributes to earlier implementations by combining aspects of both place-based and person-based accessibility measures. To this end, place-based accessibility measures are derived from a person-based framework by considering space–time prisms that are centred at service facilities rather than individual anchor points. The implementation is also innovative by explicitly accounting for the opening hours of service delivery in its accessibility measurement. In addition, the toolkit is aimed to be user-friendly and to generate insightful and comprehensible results for non-technically oriented users, which is illustrated in a brief case study about library accessibility in Ghent (Belgium).
Moving objects are commonly handled using quantitative methods and information. However, in many ... more Moving objects are commonly handled using quantitative methods and information. However, in many cases, qualitative information can be more efficient and more meaningful than quantitative information. A lot of research has been done in generating, indexing, modelling and querying network-based moving objects, but little work has been done in building a calculus of relations between these objects in a qualitative way. In this paper, we introduce a formal definition of how to represent and reason about the relative trajectories of pairs of objects moving along a network.
Lecture Notes in Computer Science, 2005
MA Rodríguez et al. (Eds.): GeoS 2005, LNCS 3799, pp. 6076, 2005. © Springer-Verlag Berlin Heide... more MA Rodríguez et al. (Eds.): GeoS 2005, LNCS 3799, pp. 6076, 2005. © Springer-Verlag Berlin Heidelberg 2005 ... A Qualitative Trajectory Calculus and the Composition ... Nico Van de Weghe1, Bart Kuijpers2, Peter Bogaert1, and Philippe De Maeyer1
Research has previously been conducted in the area of generating, indexing, modelling and queryin... more Research has previously been conducted in the area of generating, indexing, modelling and querying network-based moving objects. However, little work has been done in building a calculus of relations between disconnected network-based mobile objects. In this paper an approach to qualitatively representing and reasoning about trajectories of pairs of objects moving along a road network is presented. We call this approach the "Qualitative Trajectory Calculus along a road Network" (QTCN). We start from the assumption that two objects are moving continuously towards each other or away from each other, and consider how to describe their joint trajectories. Since the distance between two objects is measured along the shortest path, specific attention will be given to changes in shortest path, and more specifically changes in direction of the velocity vector of an object with reference to the shortest path between two objects. A conceptual neighbourhood diagram is presented, that forms the basis for a representation of a conceptual animation.