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A Conceptual Framework and Comparison of Spatial Data Models
Abstract
IntroductionTheoretical FrameworkExamples of Traditional Geographic Data ModelsRecent Developments in Spatial Data ModelsFuture Developments in Spatial Data HandlingSummary and Conclusions
References
... A field-based model treats geographic informafield-based model tion as collections of spatial distributions. In a field-based model, each Object versus field Space may be conceptualized in two distinct ways: either as a set of locations with properties (absolute space, existent in itself) or as a set of objects with spatial properties (relative space, dependent upon other objects, see Chrisman, 1975Chrisman, , 1978Peuquet, 1984). This dichotomy turns out to have far-reaching implications for spatial modeling, where absolute space is modeled as a set of fields and relative space as collections of spatially referenced objects. ...
... 4.2.1 Good discussions of the relative merits of field-based against object-based models (although sometimes not using that terminology) are contained in Peuquet (1984), Morehouse (1990), Goodchild (1991), and Couclelis (1992). 4.3.1 Chrisman (19974.3.1 Chrisman ( , 1998 provides an introduction to and critique of Stevens' four levels of measurement, from a GIS perspective. ...
... Examples of planar regular and irregular nested tessellations are shown below. The first two (triangle and square) are regular, but the third (hexagon) is not, because hexagons cannot fit together to make a larger hexagon (see Peuquet, 1984). The nested square tessellation of the plane leads to the quadtree data structure, discussed in Chapter 6. ...
... Cette intégration du temps dans les SIGs a constitué un sujet de recherche depuis la fin des années 1980 et est encore en plein développement. Cela a débuté avec (Peuquet, 1984) qui, en présentant une taxonomie et uné etude approfondie des modèles de données spatiales, a clairement mentionné l'importance du temps dans les systèmes d'informations géographiques et la nécessité d'une meilleur intégration de la dimension temporelle. Toutefois, il nous faut attendre les travaux de (Langran and Chrisman, 1988) pour in-1 troduire, pour une première fois, quelques concepts fondamentaux d'un SIG temporel. ...
Grâce au développement permanent de la technologie des capteurs géo-localisés et des infrastructures d'acquisition de données, les chercheurs en sciences environnementales et urbaines disposent de nouvelles possibilités pour étudier les phénomènes géographiques à différentes échelles temporelles et spatiales. En effet, le large éventail de données géographiques désormais disponibles offre de multiples possibilités d'exploration des données spatio-temporelles pour une meilleure compréhension de la nature de la dynamique des processus environnementaux sous-jacents. Face à de telles opportunités, des défis majeurs se manifestent et soulèvent cependant de nombreuses questions méthodologiques liées à la conceptualisation et à la représentation numérique de l'espace-temps. L'objectif de cette recherche consiste à développer une modélisation hybride de l'espace géographique qui réconcilie les approches champs et objet et qui prenne en compte une fine intégration de la dimension temporelle. Sur la base de ce modèle de données spatio-temporel hybride, notre approche spécifie un large éventail de requêtes spatio-temporelles qualifiées d'hybrides et qui permet d’exploiter le potentiel du modèle développé. La finalité consiste à explorer et de valider dans quelle mesure une telle représentation hybride puisse fournir une modélisation faisable et sémantiquement riche, et d'autre part de permettre la définition de mécanismes de manipulation au niveau d'un langage d'interrogation pour l'étude de phénomènes géographiques complexes. Le contexte de validation proposé est celui d’un phénomène de dynamique de géomorphologie marine. Ce cas est considéré comme un exemple pertinent de phénomène environnemental pour lequel une représentation hybride a un sens. Une série d'expériences de performance et d'extensibilité sont finalement rapportées et montrent comment l'ensemble du modèle se comporte.
... Dans un S.I.G. beaucoup de types de données concernant objets, phénomènes et valeurs sont enregistrées. Ces données peuvent être divisées en deux catégories primaires (Dangermond J., 1982, Peuquet D.J., 1984, Robinson A.H., et al, 1995: ...
... Usually, simplicial complexes [46] are used as a data model for the geometric modelling of natural structures [49,50] in the geosciences because they allow a better approximation of the geometry in 3D space than grids and ease geo-computation, as the algorithms can be broken down to basic geometric operations on triangles and tetrahedra. Whenever the data are modelled over a period of time, multiple time steps can be combined and form a spatio-temporal object. ...
Without geospatial data management, today´s challenges in big data applications such as earth observation, geographic information system/building information modeling (GIS/BIM) integration, and 3D/4D city planning cannot be solved. Furthermore, geospatial data management plays a connecting role between data acquisition, data modelling, data visualization, and data analysis. It enables the continuous availability of geospatial data and the replicability of geospatial data analysis. In the first part of this article, five milestones of geospatial data management research are presented that were achieved during the last decade. The first one reflects advancements in BIM/GIS integration at data, process, and application levels. The second milestone presents theoretical progress by introducing topology as a key concept of geospatial data management. In the third milestone, 3D/4D geospatial data management is described as a key concept for city modelling, including subsurface models. Progress in modelling and visualization of massive geospatial features on web platforms is the fourth milestone which includes discrete global grid systems as an alternative geospatial reference framework. The intensive use of geosensor data sources is the fifth milestone which opens the way to parallel data storage platforms supporting data analysis on geosensors. In the second part of this article, five future directions of geospatial data management research are presented that have the potential to become key research fields of geospatial data management in the next decade. Geo-data science will have the task to extract knowledge from unstructured and structured geospatial data and to bridge the gap between modern information technology concepts and the geo-related sciences. Topology is presented as a powerful and general concept to analyze GIS and BIM data structures and spatial relations that will be of great importance in emerging applications such as smart cities and digital twins. Data-streaming libraries and “in-situ” geo-computing on objects executed directly on the sensors will revolutionize geo-information science and bridge geo-computing with geospatial data management. Advanced geospatial data visualization on web platforms will enable the representation of dynamically changing geospatial features or moving objects’ trajectories. Finally, geospatial data management will support big geospatial data analysis, and graph databases are expected to experience a revival on top of parallel and distributed data stores supporting big geospatial data analysis.
... Finally, a hierarchical quadtree is formed. Quadtree decomposition is a typical planar recursive decomposition [20]. This method is suitable for the case where the data isomorphism and distribution are relatively balanced [21]. ...
Map overlay analysis is essential for geospatial analytics. Large scale spatial data pressing poses challenges for geospatial map overlay analytics. In this study, we propose an efficient parallel algorithm for polygons overlay analysis, including active-slave spatial index decomposition for intersection, multi-strategy Hilbert ordering decomposition, and parallel spatial union algorithm. Multi-strategy based spatial data decomposition mechanism is implemented, including parallel spatial data index, the Hilbert space-filling curve sort, and decomposition. The results of the experiments showed that the parallel algorithm for polygons overlay analysis achieves high efficiency.
... O modelo de dados é o cerne conceitual de um sistema de informação, pois define as entidades, os relacionamentos, as operações e as regras para manter a integridade do banco de dados (CODD, 1990). Peuquet (1984) define modelo de dados como uma descrição geral de conjuntos específicos de entidades e das relações entre estes conjuntos de entidades. Segundo o autor, a característica mais básica de um modelo de dados é que ele é uma abstração da realidade. ...
The objective of this research was to develop a spatio-temporal database to check the impact of changes in the characteristics of a watershed in runoff. The focus of this research was the development and adaptation of methods and techniques to incorporate the temporal dimension in spatial databases. Thus, we considered the following questions: i) the need to consider the drainage in the process of planning the land use; ii) the need to consider watershed as the unit of planning and management and iii) the fact that Geographic Information Systems (GIS) are currently statics and that present limitations regarding the representation and manipulation of the temporal dimension of data, which restricts their applicability to examine the dynamic changes that occur in a watershed and the estimated impact on runoff. The conceptual modeling was performed using the techniques of entity-relationship (ER), based on the semantic analysis of the variables involved in testing the characteristics of a watershed,and on the runoff estimation. The organization of the changes that occur over time in the characteristics of the watershed was made based on a time-based approach. For the storage structure of spatiotemporal entities, we used the object-based approach. Queries were developed to perform alphanumeric, spatial, temporal and spatiotemporal data and to quantify the characteristics of the watersheds. The SCS-CN method was applied to estimate the runoff. A pilot test was conducted to validate the logical model and to verify the integrity of BDET. The study area was the Atuba river watershed in the metropolitan region of Curitiba, Parana. This basin has undergone a major process of urbanization and is currently considered the second most urbanized watershed in the region. The pilot test found that the BDET designed meets the requirements and responds to queries defined in the survey, being a tool to assist in the management of stormwater and land use.
Globally, communities are constantly responding and coping with risks due to climate and land‐use land‐cover change. In Southeast Asia, impacts from these changes are evident in hydro‐meteorological hazards that are projected to increase in anomaly, frequency and magnitude. In response to these risks, the concept of climate‐community resilience is widely applied in research and policy‐making. Although previous studies have adopted index‐based approaches, an over‐simplified urban‐rural dichotomy is perpetuated in visualization and disaster governance. This study thus aims to uncover how the geographic dynamics of urban‐rural resilience can be assessed and represented as a continuous, uneven and active process. With drought as the hazard of concern, this study models resilience along the urban‐rural continuum in Yangon, Myanmar. The results show that resilience is not dichotomous in form. Areas of high resilience are mostly located along boundaries of contiguous administrative towns, rather than abiding by the physical landscape morphology. It also depends on the intrinsic fabric of a community, that is, its degree of urbanism and ruralness. The study supports the usage of continuous representation in future resilience assessments for relatively urbanized and urbanizing regions. It encourages the conceptualization of disaster governance that considers the decentralization of resilient systems.
ANÁLISE ESPACIAL DE ESTRUTURAS INTRA-URBANAS: O
CASO DE SÃO PAULO
It has been shown previously that the Voronoi diagram for a set of n points in the Euclidean plane can be constructed in O(n log n) time, and that this is optimal to within a constant factor. The notion of a Voronoi diagram is generalized to include Voronoi diagrams for line segments and other geometric figures and an algorithm to construct the Voronoi diagram for a set of n line segments is presented. This algorithm can be extended to compute Voronoi diagrams for circles, polygons, and other figures.
The use of curves to represent two-dimensional structures is an important part of many scientific investigations. For example, geographers use curves extensively to represent map features such as contour lines, roads, and rivers. Circuit layout designers use curves to specify the wiring between circuits. Because of the very large amount of data involved and the need to perform operations on this data efficiently, the representation of such curves is a crucial issue. A hierarchical representation consisting of binary trees with a special datum at each node is described. This datum is called a strip and the tree that contains such data is called a strip tree. Lower levels in the tree correspond to finer resolution representations of the curve. The strip tree structure is a direct consequence of using a special method for digitizing lines and retaining all intermediate steps. This gives several desirable properties. For curves that are well-behaved, intersection and point-membership (for closed curves) calculations can be solved in 0(log n ) where n is the number of points describing the curve. The curves can be efficiently encoded and displayed at various resolutions. The representation is closed under intersection and union and these operations can be carried out at different resolutions. All these properties depend on the hierarchical tree structure which allows primitive operations to be performed at the lowest possible resolution with great computational time savings.
Strip trees is a linear interpolation scheme which realizes an important space savings by not representing all the points explicitly. This means that even when the overhead of the tree indexing is added, the storage requirement is comparable to raster representations which do represent most of the points explicitly.
Although tessellations of Thiessen polygons are attractive conceptually as simple spatial models, their value in this regard is limited by the restrictive nature of both the model assumptions and the patterns which they generate. This paper suggests two simple ways by which Thiessen polygon models can be modified to produce what are designated "weighted polygon" models. The approach involves the recognition that the edges in a tessellation of Thiessen polygons are a special case of Descartes' ovals. Two specific, weighted polygon models are produced using other realizations of Descartes' ovals. Both new models are given both assignment and growth interpretations, and their relationships with other existing geographic models are explored. Using equivalencies identified in this way, applications of the models are examined.
This chapter discusses the pattern and search statistics. Most of the paper discusses one particular application and the work presented is descriptive of approaches to that application. In situations that arise in artificial intelligence, initial null and alternative hypotheses must be modified as information is obtained. One modification concerns the establishment of other hypotheses to which the observed last datum also contributes and a decision regarding as to which pair of null and alternative hypotheses to emphasize in further testing.
A method for assembling and managing global terrain data is presented, the Geodesic Elevation Model. Derived from concepts in geometry, geography, geodesy, applied mathematics and computer science, GEM is designed to digitally archive and access measurements of points given in latitude, longitude and elevation from any source, by embedding them in a regular, polyhedral data structure. To do this, the model recursively tessellates a regular solid, either an octahedron or an icosahedron, into equilateral triangular facets. Spot measurements are encoded by successive approximation, mapping a given geodetic location to proximal centroids of nested triangles.-from Author
Current graphic devices suitable for high-speed computer input and output of cartographic data are tending more and more to be raster-oriented, such as the rotating drum scanner and the color raster display. However, the majority of commonly used manipulative techniques in computer-assisted cartography and automated spatial data handling continue to require that the data be in vector format. This situation has recently precipitated the requirement for very fast techniques for converting digital cartographic data from raster to vector format for processing, and then back into raster format for plotting. The current article is part one of a two-part paper concerned with examining the state-of-the-art in these conversion techniques. In part one, algorithms to perform all phases of the raster-to-vector process are systematically outlined, and then compared in general terms. Examples of existing implementations of the raster-to-vector process are also described and evaluated. Part two will outline and compare ...
