Catálogo de publicaciones - libros

CoMoGIS 2005 was the second International Workshop on Conceptual Modeling in GIS held in conjunction with the annual International Conference on Conceptual Modeling (ER’05) on October 27^ th , 2005 in Klagenfurt, Austria. Following the success of CoMoGIS 2004 (held in Shanghai, China), its aim was to bring together researchers investigating issues related to conceptual modeling for geographic and spatial information handling systems, and to encourage interdisciplinary discussions including the identification of emerging and future issues.

This paper shows how to extend and generalize Tomlin’s Map Algebra to apply uniformly for spatial, temporal, and spatio-temporal data. A specific data layer can be seen as a function from location to a value (Goodchild’s geographic reality). Map layer but also time series and other similar constructions are functors, mapping local operations to layers, time series, etc. Tomlin’s Focal Operations are mostly convolutions and the zonal operations are summaries for zones. The mathematical framework explained justifies polymorphic overloading of operation names like + are made to work for layers, time series, etc. There is also a uniform method to apply user-defined local functions to them. The result is a consistent extension of Map Algebra with a simplified user interface. The implementation covers raster operations and demonstrates the generality of the concept.

Modelling moving points is a subject of interest that has attracted a wide range of spatio-temporal database research. Efforts so far have been oriented towards the development of database structures and query languages. The preliminary research presented in this paper introduces a formal analysis of spatio-temporal trajectories, where the objective is to complement current proposals by a categorization of the underlying processes that characterize moving points. The model introduced identifies the semantic exhibited by point versus point, point versus line and point versus region trajectories.

The formal specification of spatio-temporal information is essential to the definition of spatio-temporal database systems. The main contribution of this work is to provide a formal specification that uses object-oriented concepts associated not only with objects but also with events as primary classes of a model. The work is based on Event Calculus and C-logic to model objects and events and to provide a language for spatio-temporal queries. This work shows the possibility to combine the snapshot view with the event view of spatio-temporal information using a formal framework that serves for specifying information, checking consistency of specification, and being a reference for query languages.

The idea of Conceptual Neighbourhood Diagram (CND) has proved its relevance in the areas of qualitative reasoning about time and qualitative reasoning about space. In this work, a CND is constructed for the Qualitative Trajectory Calculus (QTC), being a calculus for representing and reasoning about movements of objects. The CND for QTC is based on two central concepts having their importance in the qualitative approach: the theory of dominance and the conceptual distance between qualitative relations. Some examples are given for illustrating the use and the potentials of the CND for QTC from the point of view of GIScience.

In order to detect the spatial conflicts in the process of spatial database updating, a refined description of spatial relationships is needed. This paper presents a topological chain model for refined line-line spatial relationships. The model integrates the topological relationships and order relationships with the metric relationships, such as intersecting angles, number of intersection points, distance between two intersection points, and area of the region formed by two intersectant curves. Based upon such detailed descriptions of the line-line relationships, the spatial conflicts can be detected automatically. The validity of the model and the efficiency of the method have been approved by automatic detection of the conflicts between rivers and contours for the national spatial database at the scale of 1:50,000.

Generalization of spatial databases consists of complicated operations including not only geometric transformations but also topological changes. The changes often result in an inconsistency between the original and derived databases. In order to control the quality of derived databases, we must assess the topological consistency. In this paper, we propose a set of rules to assess topological consistency for the collapse operation. The rules are based on a rigorous classification of topological properties in a collapse operation. By these rules, we can detect inconsistent topological changes in the generalization process and improve the quality of derived databases.

Measuring semantic similarity among concepts is the core method for assessing the degree of semantic interoperability within and between ontologies. In this paper, we propose to extend current semantic similarity measures by accounting for the spatial relations between different geospatial concepts. Such integration of spatial relations, in particular topologic and metric relations, leads to an enhanced accuracy of semantic similarity measurements. For the formal treatment of similarity the theory of conceptual vector spaces—sets of quality dimensions with a geometric or topologic structure for one or more domains—is utilized. These spaces allow for the measurement of semantic distances between concepts. A case study from the geospatial domain using Ordnance Survey’s MasterMap is used to demonstrate the usefulness and plausibility of the approach.

Continuous K nearest neighbor queries (C-KNN) on moving objects retrieve the K nearest neighbors of all points along a query trajectory. In existing methods, the cost of retrieving the exact C-KNN data set is expensive, particularly in highly dynamic spatio-temporal applications. The cost includes the location updates of the moving objects when the velocities change over time and the number of continuous KNN queries posed by the moving object to the server. In some applications (e.g., finding my nearest taxies while I am moving), obtaining the perfect result set is not necessary. For such applications, we introduce a novel technique, AC-KNN, that approximates the results of the classic C-KNN algorithm, but with efficient updates and while still retaining a competitive accuracy. We evaluate the AC-KNN technique through simulations and compare it with a traditional approach. Experimental results are presented showing the utility of our new approach.

In order to analyze the behavior of moving objects, a measure for determining the similarity of trajectories needs to be defined. Although research has been conducted that retrieved similar trajectories of moving objects in Euclidean space, very little research has been conducted on moving objects in the space defined by road networks. In terms of real applications, most moving objects are located in road network space rather than in Euclidean space. In this paper, we investigate the properties of similar trajectories in road network space. And we propose a method to retrieve similar trajectories based on this observation and similarity measure between trajectories on road network space. Experimental results show that this method provides not only a practical method for searching for similar trajectories but also a clustering method for trajectories.