No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Strong Integration of Spatial Domains and Operators in a relational Database System.
Abstract
Managing and manipulating spatial data requires selective access to these data, performance at access level, and data protection. The need for a single spatial database system, integrating in a single model both alphanumeric and geometric data, is discussed. Such a database system, GéoSabrina, has been developed as an extension of an already existing relational database system. The system supports spatial data with corresponding spatial operators. Data manipulation is easily made through a spatial extension of SQL. Optimization techniques are used, providing for a strong integration of spatial operators based on spatial indexing and join-indices techniques. Built-in spatial functionalities may be further extended by application programmers through object oriented features.
... Clearly, neither of these two architectures takes full advantage of database technology, since conventional DBMSs do not provide efficient manipulation of spatial data. To overcome this limitation, a new research effort was next undertaken in the area of spatial databases [6][7][8][9][10][11][13][14][15][16][17][18][19][20][21][22][23], leading to a new set of approaches, termed DBMS-centric in [24]. As a result of the research in this area, the last generation commercial and open-source DBMSs [28][29][30][31] include extensions of models that enable the storage and management of spatial data and a spatial SQL as well, compliant with already existing standards [32,33]. ...
... As an example of the former, only the surface parts are obtained by the spatial intersection of two surfaces in [9,10,12,18,20,23,25,26,28,29,52] whereas a second operation is required to obtain the line parts in [8,38,40,41,49]. Regarding the latter, data types of the form set of spatial objects are adopted in [8,10,11,13,14,19,25,27,30,36,38,40,41,49,50], spatio-temporal data types are considered in [36,38,40,41,43,45,50], and complex data structures, such as nested-relational, object-relational, and object-oriented, are used in [6,16,19,22,23,51,52]. Also, object-relational structures are used in [28,29,30] to implement complex data types. ...
... Additional limitations identified in the various spatial and spatio-temporal approaches can be resumed as follows. Some approaches restrict to only informal presentations either of the data types or of the functionality of the operations [6,7,9,12,14,17,18,20,21,34,36,[44][45][46][49][50][51]. The empty set is treated as a valid spatial object in [7,8,10,13,14,18,19,26,28,29,32,33,38,40,41,49,50]. ...
An extension of SQL is formalized for the management of spatio-temporal data, i.e. of spatial data that evolves with respect to time. The syntax and semantics of the extension is fully consistent with SQL. The formalism is very general; in that the extension can be applied to any kind of data, either temporal or spatial or conventional.
... Spatial data are recorded in relations that satisfy 1NF in Larue, Pastre and Viémont (1993); Roussopoulos, Faloutsos and Sellis (1988); Egenhofer (1994); Scholl and Voisard (1992); Gargano, Nardelli and Talamo (1991); Chen and Zaniolo (2000); and Böhlen, Jensen and Skjellaug (1998). They either define a relational algebra or they extend SQL by functions and relational operations. ...
... Only one spatial type, GEOMETRY, is supported in Larue et al. (1993). An element of this type is a set of spatial objects, either points, polylines or polygons ( Figure 5(a-c)). ...
... Overlay is supported only between maps of the same cover. Finally, the characteristics of the restriction to spatial data management of the spatiotemporal model defined in Yeh and de Cambray (1995) match those of Larue et al. (1993) discussed above. ...
The chapter identifies properties that a spatial data model, dedicated to support spatial data for cartography, topography, cadastral and relevant applications, should satisfy. The properties concern the data types, data structures and spatial operations of the model. A survey of various approaches investigates mainly the satisfaction of these properties. An evaluation of each approach against these properties also is included.
... Clearly, neither of these two architectures takes full advantage of database technology, since conventional DBMSs do not provide efficient manipulation of spatial data. To overcome this limitation, a new research effort was next undertaken in the area of spatial databases [6][7][8][9][10][11][13][14][15][16][17][18][19][20][21][22][23], leading to a new set of approaches, termed DBMS-centric in [24]. As a result of the research in this area, the last generation commercial and open-source DBMSs [28][29][30][31] include extensions of models that enable the storage and management of spatial data and a spatial SQL as well, compliant with already existing standards [32,33]. ...
... As an example of the former, only the surface parts are obtained by the spatial intersection of two surfaces in [9,10,12,18,20,23,25,26,28,29,52] whereas a second operation is required to obtain the line parts in [8,38,40,41,49]. Regarding the latter, data types of the form set of spatial objects are adopted in [8,10,11,13,14,19,25,27,30,36,38,40,41,49,50], spatio-temporal data types are considered in [36,38,40,41,43,45,50], and complex data structures, such as nested-relational, object-relational, and object-oriented, are used in [6,16,19,22,23,51,52]. Also, object-relational structures are used in [28,29,30] to implement complex data types. ...
... Additional limitations identified in the various spatial and spatio-temporal approaches can be resumed as follows. Some approaches restrict to only informal presentations either of the data types or of the functionality of the operations [6,7,9,12,14,17,18,20,21,34,36,[44][45][46][49][50][51]. The empty set is treated as a valid spatial object in [7,8,10,13,14,18,19,26,28,29,32,33,38,40,41,49,50]. ...
An SQL extension is formalized for the management of spatio-temporal data, i.e. of spatial data that evolves with respect
to time. The extension is dedicated to applications such as topography, cartography, and cadastral systems, hence it considers
discrete changes both in space and in time. It is based on the rigid formalization of data types and of SQL constructs. Data types are defined in terms of time and
spatial quanta. The SQL constructs are defined in terms of a kernel of few relational algebra operations, composed of the well-known operations of the 1NF model and of two more, Unfold and Fold. In conjunction with previous work, it enables the uniform management of 1NF structures that may contain not only spatio-temporal
but also either purely temporal or purely spatial or conventional data. The syntax and semantics of the extension is fully
consistent with the {SQL:2003} standard.
... It is noticed, however, that such an operation may also have practical interest between lines, too, e.g. between a river and a highway that runs partly over it. As a last observation, formalism, either of spatial data types or of operations, is missing in [2, 5, 14, 18, 19, 20, 21, 22, 23, 26, 27, 28, 33, 34, 38, 39, 43]. As opposed to the above approaches, the spatial data model proposed in the present paper overcomes all the above limitations. ...
... N N N N N Spatial data structures (v) Complex structures not required N/A N/A N/A N Y Y N N/A N Y Y Y Y Y Y Y Y N Y Y Y Y N Y Y N N Y Y Y Y N Y Y Y N N Y (vi) No limitations on structures N/A N/A N/A N P P N N/A N P Y Y Y Y Y Y Y P Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Spatial operations (vii) Formalism N Y Y P N/A N/A N/A N/A N N/A Y Y N N N N N N Y Y N N N Y Y Y Y N N N/A N/A N/A N N N/A N/A N/A N (viii) No data loss (iii) Empty Set not a Valid Spatial Object: As has been reported, such a spatial object does not have practical interest. However, the result of a spatial operation may yield the empty set in [6, 16, 17, 18, 19, 20, 22, 25, 30, 32, 33, 34, 36, 39, 40, 43] whereas in [35] such a result is automatically replaced by the null value. ...
Operations on spatial objects have great individuality. As a consequence, the spatial data modelling approaches, which have been proposed, have to consider either data types of the form set of spatial objects or non-1NF data structures or a limited spatial functionality of the operations. The model formalized in this paper overcomes these limitations. In particular, spatial quanta are defined and, based on them, spatial data types are formalized including point, line and surface. All the types consist of connected spatial objects that can be involved in all the spatial operations, which are defined. A relational formalism is developed for the management of spatial data. It considers non-nested relational data structures. The relational algebra consists of a kernel set of operations, the ordinary relational operations and two more. All others are defined in terms of those in the kernel. It is shown that the management of spatial data actually reduces to the management of relational data. The model achieves, and generalizes further, commonly accepted spatial operations. Although the formalism restricts to the management of 2D spatial data, its extension to n-D is straightforward. In conjunction with previous research, the algebraic operations are closed and enable the uniform management of any type of data, i.e. spatial, spatio-temporal, interval and conventional.
... A lot of efforts are under progress to elaborate innovative solutions for the representation and exploration of complex database applications. In the context of geographical databases, several spatial data models have been identified through the integration of geometrical and topological principles (e.g., David 1993, Guting 1989, 1993, Haas 1991, Kolovson 1993, Larue 1993, Scholl 1989, Van Oosterom 1993. Similarly, many proposals have been defined to formalise spatial query languages within databases (e.g., Brossier-Wansek 1995, Egenhofer 1990, Frank 1982, Orenstein 1988. ...
... The introduction of spatial operators, (e.g., in the select clause), improves the benefit of spatial operators as a new spatial semantics may be derived from their application (Guting 1989, Haas 1991, Larue 1993, Orenstein 1988). ...
Within GIS, networks have been mainly represented at the geometrical level. This paper demonstrates that the definition of additional levels of abstraction extend the semantics of GIS networks. Networks are analyzed and modelled at the conceptual and logical levels, independently of the underlying geometrical representation. The management of this two-levels representation leads to the development of a new interpretation of the database projection operator. This new operator is oriented to a semantic representation of a network. Network component properties are identified at the node and link component levels. We define four semantic constants: Global, SubsetN, SubsetL and SubsetN,L. The semantic of alphanumeric properties are identified and their propagation with the application of network operators is characterised in function of the semantic constants. The closure of network manipulations on the database schema supports the definition of a data model that integrates the result of a network operator. This data model is built as a subset of the data models involved in network operators.
... Os bancos de dados espaciais proporcionam funções e índices especiais para consultar e manipular os dados espaciais usando linguagens de consulta, como a SQL (Structured Query Language). Com isso, muitas das funcionalidades dos SIG podem ser incorporadas diretamente no sistema de banco de dados (Larue et al., 1993;Bagg e Ryan, 2005). Como argumentam Obe e Hsu (2010), embora os bancos de dados espacias sejam frequentemente utilizados apenas para armazenar dados espaciais, eles possuem diversas ferramentas que possibilitam também análises desses dados. ...
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.
... No entanto, o suporte à representação matricial ainda é uma questão em desenvolvimento. As duas principais iniciativas de fornecer suporte a dados matriciais embutidas em uma extensão espacial de maneira similar aos dados vetoriais são o GeoRaster que faz parte da extensão Oracle Spatial [9] e mais recentemente o PostGIS raster para o PostgreSQL [10]. ...
Resumo. Este artigo tem como objetivo principal apresentar os resultados da aplicação de funcionalidades da extensão espacial PostGIS raster para o proces-samento digital de uma imagem de sensoriamento remoto referente a uma pro-propriedade rural localizada no município de Bagé, Rio Grande do Sul, Brasil. Os procedimentos utilizados para a realização do estudo podem ser agrupados em: 1) definição da área de estudo; 2) aquisição de imagens de satélite; 3) in-serção das imagens no Banco de Dados; 4) desenvolvimento de consultas refe-rentes à técnicas de processamento digital de imagens; 5) Cálculo de NDVI, ve-torização e cálculo de área de classes de uso e cobertura da terra. As funcionali-dades do PostGIS raster mostraram-se satisfatórias para o armazenamento, a manipulação e para realizar procedimentos simples de processamento das ima-gens da propriedade rural. Palavras Chaves: Dados Raster, manipulação de dados geográficos.
... Numerous Geographical Information Systems exist. They may be classified in four generations as described in [TDY93]. ...
... Los SIG se pueden clasificar en cuatro generaciones dependiendo de la solución adoptada para almacenar la información espacial, tal y como se describen Larue et al. (1993) y queda representado en la figura 2. ...
En este artículo se presentan de forma resumida la metodología y principales resultados del proyecto SIGTEBAL "Sistema de Información Geográfica para el diseño, gestión, análisis y planificación de rutas de transporte escolar en las Baleares". Se trata de un ejemplo de aplicación de los Sistemas de Información Geográfica al área del transporte (SIG-T). El SIGTEBAL se contruye a partir del diseño de una base de datos geográfica de la red viaria regional de Mallorca a la cual se le incorpora información correspondiente al sistema de rutas de transporte escolar (paradas, itinerarios, colégios, etc). El proceso análitico y de planificación de rutas se realiza a partir de la implementación de diversos métodos de optimización. El objetivo final ha sido el diseño y la implementación de un aplicativo orientado al personal técnico de la Consejería de Educación del Gobierno Balear para para facilitar las tareas de gestión de rutas escolares.
... Much work have been done on modelling on geometric data in the past two decades (see for instance, 4,19,17,18,1,8,21,2,14,9,10,11,15]). In this Section, we review existing proposals on data models, in particular, their geometric operators, for geometric databases. ...
This paper describes a data model and its query language for a database system developed at the University of Waterloo. The system, called QL/G, is designed for managing data in a geometric database. Geometric data types like general regions, lines and points are directly supported as built-in data types in the system. The query language, also called QL/G, is intended to be a general-purpose spatial query language for manipulating both alphanumeric as well as geometric data. The proposed language is a modular, strongly-typed functional language with an SQL flavour. It consists of two main categories: geometric and non-geometric operators. Non-geometric operators corresponds to a data retreival language in nested relational database systems. Geometric operators are designed, both syntactically and semantically, to be independent of non-geometric operators. This intends to achieve the objective that the set of geometric operators be independent of, but incorporable into, any existing set...
... Hence, a second generation of GIS were built upon the technology of extended and extensible relational database systems. Examples of these GIS are GEO++ [ViOo92] which is built upon Postgres [SRH90], System 9 [EcUf89], Smallworld [CNT90], and GeoSabrina [LPV93]. ...
.................................................................................................... 1 CHAPTER 1 -- INTRODUCTION .................................................................... 3 CHAPTER 2 -- AN INTRODUCTION TO GEO-INFORMATION SYSTEMS ... 7 2.1 What is a Geo-Information System? ......................................................... 7 2.2 Data found in a GIS .................................................................................. 10 2.2.1 Non-Spatial or Thematic Data ...................................................... 11 2.2.2 Spatial Data ...................................................................................... 11 2.2.3 Temporal Requirements of GIS-Data ........................................... 12 2.3 GIS-Databases and Application Integration ......................................... 13 2.3.1 Types of GIS-Databases ................................................................. 13 2.3.2 Coupling GIS-Applications and GIS-Databases .....
... In the GIS area, the first extension to 3D goes through relief (Weibel et al, 1992) integration. A second extension, proposed in the GéoSabrina prototype of the PRiSM laboratory (Larue et al, 1993;Chrétien et al, 1994), consists in associating a minimal and a maximal elevations to boundary points. To take into account complex shapes of 3D geographical data and to integrate 2D and 3D data with the relief, the MD (multidimensional) model is proposed (de Cambray et al, 1994). ...
Nowadays, spatial modelling is mainly 2D. In applications like architecture or urban planning, data are defined in a 3D space. However, there are few spatial models suitable to the specificity of 3D geographical data. Such models describe geographical environment, where objects are contiguous and are of different nature (lines, surfaces or volumes). Connections between objects-also called topological relationships-, like adjacency or intersection, give an abstraction of global organization of spatial objects. For this reason, topological models are the most prevalent in 2D GIS. Some authors have defined 3D topological models, but if those models are well adapted to CAD applications, they do not allow for the specificity of geographical data. Adjacency can be specified by horizontal or vertical direction. Hence, an object may be close to its neighbours, while in the vertical direction one object may support another one. This reflection led us to define a pragmatic topological model to d...
We present a new extensible, object-oriented data model for geographic infor-mation systems and a corresponding extensible SQL-like query language. This model is intended to be a general base for the development of geographic infor-mation systems. Hence, our model supports both two-and three-dimensional data as well as raster-and vector-based data. In addition, the objects may have several thematic and geometric attributes. Basically we propose a hierarchy of classes describing so called spatial objects. Classes required to describe a concrete application are modelled as subclasses of these abstract classes. The presented query language generalizes earlier proposals of SQL-like query languages for geographic information systems.
du Data Mining et de bases de données spatiales (BDS) offre de nouvelles perspectives pour l'analyse spatiale des données géographiques. Cette combinaison amène au domaine du Data Mining Spatial (DMS). Cet article décrit dans une première partie les techniques spécifiques de gestion de bases de données spatiales dans un Système d'Informations Géographiques (SIG). La seconde partie introduit le concept de Data Mining Spatial en soulignant sa spécificité par rapport au Data Mining sur des bases relationnelles. Elle souligne l'existence de deux approches au DMS, l'une issue du domaine d'apprentissage sur des bases de données et l'autre des statistiques orientées analyse spatiale. Les méthodes développées dans l'une et l'autre de ces deux approches sont décrites et classées par catégorie selon leur rôle ou la forme de connaissance extraite. L'étude comparative de ces approches montre leurs similarités, leurs différences et leur complémentarité. Elle permet de conclure, d'une part, que la combinaison des deux approches de DMS serait profitable dans le processus d'analyse et, d'autre part, que les relations spatiales jouent un rôle central dans le processus de Data Mining et par conséquent que les BDS qui permettent de les déterminer sont d'autant plus importantes. ABSTRACT. The combination of Data Mining and Spatial Database (SDB) offer new prospects for spatial analysis in geographical applications. This combination brings to the field of Spatial Data Mining (SDM). This paper describes, in a first part, the specific techniques for the management of spatial databases in a Geographical Information System (GIS). The second part introduces the concept of Spatial Data Mining by underlining its specificity with regard to Data Mining on relational databases. We point out that there exists two approaches for the SDM. The first comes from spatial database learning, while the second is based on spatial statistics field. Methods developed in both approaches are described and classified by category according to their role or the type of extracted knowledge. The comparative study of these two approaches shows their similarities, their differences and their complementary. We conclude first, that the combination of the two SDM approaches would be valuable in the analysis process; second that spatial relationships play a central role and accordingly, SDB that allow their computation are all the more interesting. MOT-CLÉS : Data Mining spatial, analyse spatiale, relations spatiales, statistiques spatiales, bases de données spatio-temporelles, systèmes d'informations géographiques.
This paper proposes a semantic geographical data model. Localization of geographical entities is defined using an abstract data type. The geographical entities' semantic is expressed through high level concepts in an entity-relationship model extended by both inheritance and propagation mechanisms.
The system's implementation is described. It takes advantage of the object-oriented aspect of the O2 DBMS, and in particular of the inheritance mechanism. Three different data structures allow to implement geographical entities' localization. They correspond to the topology description levels described in modern exchange formats. A principle of independence between data structures and operations is defined. This principle allows avoiding the re-questioning of the definition of a process if the data structure must be modified.
Lastly the described system has been effectively developed and is used with sets of a large volume of real data produced by the French Institut Gographique National (IGN).
An end-user query of a Geographical Information System (GIS) can formally be defined as the application of a set of operators (spatial or not). Geographical Information Systems used for Transportation (GIS-T) must provide a path evaluation operator. For example, an end-user query may involve a selection based on alphanumeric criteria, an evaluation of path, and a spatial intersection. This composition of operators and the fact that the evaluation of a path may not provide a unique result impose the definition of a query resolution model or a database query language able to support this composition. In this paper we present a query resolution model. The use of multi-criteria analysis and the definition of aggregates in a query (nearly mandatory) may involve ambiguities in the final presentation of the results to an end-user. The formal modeling of query results must take into account this risk. The philosophies of a query definition and the presentation of the results may be different (e.g., formular vs visual). The management of query results must take into account the data model associated with the query results, the results themselves (metabase/database), and the interpretation. The interpretation avoids errors due to visual ambiguities of an operator with an aggregate function.
This paper presents a survey of different approaches for searching information from geographic information systems (GISs) and spatial databases. The existing dichotomy between querying and navigation is highlighted and we emphasize the need to overcome it. Five categories of query languages can be identified: (1) natural languages, (2) artificial languages (e.g. extensions of SQL), (3) tabular languages: use of skeletons or forms, (4) graphical languages: use of symbols, which are only graphical conventions (like in the entity-relationship diagrams) and (5) visual languages: use of visual metaphors (e.g. icons, blackboard metaphor and map-overlay metaphor). The principles of each of them are presented. Respective strengths and weaknesses are pointed out, based on a predefined query. The last part of this paper is devoted to the hypermedia approach and describes the navigation in a hyperbase.
Global natural disasters have caused billions of dollars of property and infrastructure damages, unexpected disruption to socioeconomic activities and tragic loss of human lives each year. It is of paramount importance to collect, maintain and manage detailed and accurate records of disastrous events for an effective risk assessment and mitigation of disaster impacts. Considerable efforts have been directed towards the establishment of databases on historic disasters but many disaster databases built are primarily a set of separate lists of historical disaster events. This paper presents a recent study that investigates effective and efficient GIS-based approaches to the representation, organisation and access of disaster information. This includes logical data models for representing disastrous events, the object-relational approach to database implementation, and internet-based user-interfaces that supports multi-mode (including map-based) database queries and flexible facilities for report generation. Key aspects of a disaster event, including the spatial-temporal dimensions of the hazard and its impacts, are considered in the development of data models and database implementation in order to support user-friendly querying and reporting operations.
Communication between end-users and spatial databases raises important
and specific issues. Unlike classical systems, it requires strong
cooperation between two major tools: spatial query language and
graphical interface. This paper addresses the problem
of building an interactive querying system for spatial databases
with an open architecture. We focus
on the following issues:
(i) design of a database-independent Graphical User Interface
(GUI) providing
query expression support and advanced user-database interaction
functionnalities
(ii) software
architecture for dealing with exchanges
between the database logical representation and a graphical representation
at the interface level (iii) implementation of spatial
data and functionnalities within a DBMS without requiring
changes in the logical data model or query language syntax.
We present a prototype coupling
the O DBMS, its query language OSql,
and C++/X-Window-based toolkits as graphical components for
the interface implementation.
this paper,we investigate if deductive object-oriented data model can be effectively exploitedfor geographic data handling. The purpose of this paper is not topresent an implementation of a geographic database, rather to demonstratethat the emerging deductive object-oriented database model is well-suitedfor handling geographic data. We illustrate this by modeling prototypicalgeographic data in ConceptBase, a deductive objectbase.
Geographical databases require rich data models to represent geographical entities, relationships between these entities and geometric data. Furthermore, interactive spatial query languages should allow users to pose ad hoc queries in languages close to standards with high level graphical interfaces. This paper shows that a system mixing object-oriented and relational modelling capabilities with an extended SQL to query classes and relations is appropriate for modelling geographical data and interacting between a user and a GIS. Following these lines, a system is currently being implemented on top of an object server as an outcome of the IMPRESS ESPRIT project.
This paper proposes a semantic geographical data model. Localization of geographical entities is defined using an abstract data type. The geographical entities' semantic is expressed through high level concepts in an entity-relationship model extended by both inheritance and propagation mechanisms.
The system's implementation is described. It takes advantage of the object-oriented aspect of the O2 DBMS, and in particular of the inheritance mechanism. Three different data structures allow to implement geographical entities' localization. They correspond to the topology description levels described in modern exchange formats. A principle of independence between data structures and operations is defined. This principle allows avoiding the re-questioning of the definition of a process if the data structure must be modified.
Lastly the described system has been effectively developed and is used with sets of a large volume of real data produced by the French Institut Géographique National (IGN).
This paper presents a synthesis on the query models and languages to manipulate a geographical database. We present the different
classes of query languages : based on predicates, based on operators without composition and based on operators with composition.
We analyze the consequences on the data model, on the expressive power and on the query modeling. The introduction of operators
as query primitives requires the closedness of these operators on geographical data. The introduction of operators increases
the expressive power allowing queries involving a composition of operators. As a path operator (with the same arguments) provides
several answers and may appear several times in a query, the query modeling must provide such an opportunity. Depending on
the required expressive power, we present the different classes of interfaces at the user’s level.
DBMS functionalities have been identified as a requirement for GIS (Geographical Information Systems). With the rise of G1S, several system architectures have been proposed for both commercial products and research prototypes, bringing G[S technology closer to database tecttnology. The approach described in this paper consists in adding spatial data capabilities to a data server while regrouping all graphical display functions into a user interface layer built as a client on the server. An SQLlike language. GQL, is proposed for the client-server interface, while a graphical language including drawings, display attributes and GQL queries is offered at the end-user interface level. An application exampte shows how this architecture can be used for fast protoo,ping with a high level of user friendliness and without writing any application code.
Spatial data models have been extensively studied during the last decade. However, requirements of a spatial database system
regardless of any specific application, have not received much attention. In this paper, a general Object-Oriented spatial
data model is introduced. This model considers a spatial database system in general, without focusing on specific features
or applications, and presents a new method for classification of spatial objects into maps. The concept of map as defined
here, is an appropriate definition for objects with arbitrary set of spatial components. This concept is similar to the one
of a map in the real world. Map definition is followed by the definition of map hierarchy and operations on maps which can
be used to answer queries that might be too complicated otherwise.
We propose a definition of a spatial database system as a database system that offers spatial data types in its data model and query language, and supports spatial data types in its implementation, providing at least spatial indexing and spatial join methods. Spatial database systems offer the underlying database technology for geographic information systems and other applications. We survey data modeling, querying, data structures and algorithms, and system architecture for such systems. The emphasis is on describing known technology in a coherent manner, rather than listing open problems.
Geographic information systems (GIS) manage geographical data and present the results visually using maps. Visual languages are well adapted to query such data. We propose to express queries sent to a GIS using symbolic maps with metaphors, i.e., visual representation of the spatial relationships making up the query. Visual languages suffer from the appearance of ambiguity. We distinguish visual ambiguities from selection ambiguities. Visual ambiguities appear when a given visual representation of a query corresponds with several interpretations. In order to define new spatial relationship, the user points out one (or several) metaphor(s) already available in the restitution space. Selection ambiguities appear when a given selection corresponds with several metaphors. We suggest palliating visual and selection ambiguities by associating a placing method with composition automata. The placing method insures to minimize level of ambiguity. We determine levels of ambiguity and user interaction complexity depending on the required expressive power. The higher the desired expressive power is, the higher the level of ambiguity is and thus the more complex the user interaction is. A prototype has been implemented to validate the placing method and the automaton allowing the highest expressive power.
We study the representation and manipulation of geospatial
information in a database management system (DBMS). The geospatial data
model that we use as a basis hinges on a complex object model, whose set
and tuple constructors make it efficient for defining not only
collections of geographic objects but also relationships among these
objects. In addition, it allows easy manipulation of nonbasic types,
such as spatial data types. We investigate the mapping of our reference
model onto major commercial DBMS models, namely a relational model
extended to abstract data types (ADT) and an object-oriented model. Our
analysis shows the strengths and limits of the two model types for
handling highly structured data with spatial components
While most current Geographical Information Systems (GIS) are 2D GIS, more and more application domains as geology, civil and military engineering, etc, need 3D GIS. The particularities and capabilities of a 3D GIS are outlined in this paper. Although 3D GIS are not much developped, some studies have already been done, especially in order to represent 3D data for geological or architectural applications. Such 3D models are generally based upon Computer-Aided Design (CAD) models. The use of 3D CAD models for representing 3D in GIS is discussed in the paper. As 3D GIS represent a 3D map, not only the surface of the terrain but also the entities set on the relief, e.g. buildings, have to be represented. The proposed 3D model for a GIS consists of representing 3D entities set on a Digital Terrain Model (DTM). These entities are represented with different approximation levels, the first two being used as index and processes accelerators and the last offering an efficient visualization suppo...
. Communication between end-users and spatial databases raises important and specific issues. Unlike classical systems, it requires strong cooperation between two major tools: spatial query language and graphical interface. This paper addresses the problem of building an interactive querying system for spatial databases with an open architecture. We focus on the following issues: (i) design of a databaseindependent Graphical User Interface (GUI) providing query expression support and advanced user-database interaction functionnalities (ii) software architecture for dealing with exchanges between the database logical representation and a graphical representation at the interface level (iii) implementation of spatial data and functionnalities within a DBMS without requiring changes in the logical data model or query language syntax. We present a prototype coupling the O2 DBMS, its query language O2 Sql, and C++/X-Window-based toolkits as graphical components for the interface implementa...
New application domains of Geographical Databases highlights the need for managing 2D, 2.5D, and 3D spatial data. Such a data management raises two problems. First, there exists spatial relationships between the different spatial data and the spatial data model have to model these relationships. These relationships allow to indicate that the spatial objects defined in a map are on another map that describes the variation of altitudes, i.e., a relief. Therefore, all the objects are described in a 3D space. The second problem is a manipulation problem. As a spatial operation manipulates a given dimensional data and as the data stored in the spatial database is not always at the dimension expected by the spatial operation, the operation execution requires to transform the data stored so as to obtain the right dimensional data. The goal of this paper is to propose a unified multidimensional data model. This model allows to store and to describe different dimensional data as well as the rel...
Practical needs in geographic information systems (GIS) have led to the investigation of formal and sound methods of describing spatial relations. After an introduction to the basic ideas and notions of topology, a novel theory of topological spatial relations between sets is developed in which the relations are defined in terms of the intersections of the boundaries and interiors of two sets. By considering empty and non-empty as the values of the intersections, a total of sixteen topological spatial relations is described, each of which can be realized in R 2. This set is reduced to nine relations if the sets are restricted to spatial regions, a fairly broad class of subsets of a connected topological space with an application to GIS. It is shown that these relations correspond to some of the standard set theoretical and topological spatial relations between sets such as equality, disjointness and containment in the interior.
IntroductionTheoretical FrameworkExamples of Traditional Geographic Data ModelsRecent Developments in Spatial Data ModelsFuture Developments in Spatial Data HandlingSummary and Conclusions
References
A central problem in modern database design is how to resolve spatial opera- tions with normal database operations in an extended relational database environ- ment. A data architecture that matches the requirements for ecien t processing of spatial queries in the extended database environment is proposed. It provides an equal opportunity for both the spatial components and the non-spatial components of the data to participate in query processing and optimization. The notion of ex- tended operators to integrate homogeneously both spatial and non-spatial operations is introduced. Although intended primarily for spatial data, extended operators also provide a proper interface for integrating multi-media data into a database environ- ment. The implications of this data architecture are presented. They include their eects on standard database operations, how spatial operations are integrated into the database management system (DBMS) for ecien t processing, and how query processing and optimization are performed in this architecture. The operations of insertion and deletion, relational-based selection and join, and spatial-based selection and join are redened in terms of extended operators. Spatial query processing is also described using extended operators. This data architecture can be built on top of an extensible database management system. Since it is dedicated towards ecien t spatial query processing, this architecture can be used for testing and validating the extensibility of such systems and their eectiv eness for supporting spatial data.
We study here how to provide the designer of geographic databases with a database query language extensible and customizable. The model presented here is a first step toward a high level spatial query language adapted to the manipulation of thematic maps.
For this, we take as an example a toy application on thematic maps, and show by using a complex objects algebra that application dependent geometric operations can be expressed through an extension of the replace operator of [AB88].
Conventional query languages focus on the retrieval and modification of data from a database to a user or a host program. Queries are usually expected to be relatively uncomplicated, leaving deeper processing functions to specialized host programs.
In contrast with this view, the language SAL [Arnb80] was designed with the goal of being able to support stepwise, in-depth analysis of data, stored and managed as relations in a specially designed statistical database system, Cantor [Kara86].
This paper surveys the design objectives, operators and grammatical structures of Geo-SAL, a successor of SAL being developed for spatial data analysis purposes.
In addition to facilities needed for representation and retrieval of spatial data, Geo-SAL includes primitives and structures which permit the solution of complex, multi-step spatial analysis problems within a coherent, declarative language.
This paper presents the management of complex objects in an extensible relational database management system. Complex objects are built using the list constructor. Complex object types are defined as relation domains encapsulated within methods written in LISP or C. User-defined domains may be described using a 'IS-A' hierarchy, which makes possible the inheritance of methods among domains. The domain methods are directly used in the external data manipulation language, which is an extended version of SQL with object oriented features (i.e., structured complex objects, methods and inheritance). When executing a query, the system selects the correct methods to apply on complex objects according to all parameter types given in method calls. With the specific LISP interpreter embedded in the DBMS, errors in functions on complex objects are detected at run time.
DBMS designed for commercial usage are not well suited for GIS because they cannot accommodate spatial data and cope with retrieval of map graphics. An overview of the architecture of a DBMS especially suited for spatial data handling is presented. For each layer, specific techniques, eg for buffer management, clustering of data, and spatial access, that are useful for GIS DBMS are indicated. Efforts to implement the PANDA DBMS are described. -from Author
Digital map data are currently available based on a variety of data structures, depending on the uses to which the data are to be put Within the major categories of vector and raster data, as well as other structures, there is a multiplicity of data formats. Further to this, data for digital map coordinates are frequently stored in a different way from attribute data pertaining to points, lines and polygons. Given these problems, this paper investigates the possibility of handling different kinds of data structures, as well as both coordinate and attribute information within a unified conceptual scheme. This scheme is expressed in terms of the design of an integrated geographical information system called GEO VIEW, which can be implemented in a relational data base environment. The structure of the tables in the data base is outlined, together with the methodology for coding different kinds of data structure into a standard form. Examples of queries are provided, using the SQL query language, to indicate how the system might be used and problems in optimizing spatial searching on a data base of this kind are addressed.
ABSTRACT Arc/Info is a generalized,system,for processing,geographic information.,It is based,on a relatively,simple,model,of geographic,space,- the,coverage,- and,contains,an extensive set,of geoprocessing,tools,which,operate,on coverages. Arc/Info is being,used,in a wide,variety,of application areas, including natural resource inventory and planning, cadastral database development and mapping, urban planning, and,cartography. The design,philosophy,and,architecture,of Arc/Info is described. This includes the spatial data model, the spatial operators, the engineering of the system as a practical software,product.
A data model for geographic information is described. Originally designed for thematic mapping and map analysis, the model lends itself to tabular data processing applications as well as automated cartography. The model is a combination of the topological model (to represent feature locations and topology) and the relational model (to represent feature attributes). -Author
GEOVIEW, an integrated system, uses relational database technology and a graphics package (Graphical Kernel System) to offer a flexible environment in which to develop applications of geographical information systems (GIS). It has facilities to represent data in different spatial data structures. Data are stored and retrieved efficiently by using variable length raw data. The unified representation offers the benefit of storing entities in a single relation and eases the process of overlaying different entities. GEOVIEW also provides a mechanism for tailoring user interfaces to suit the needs of different applications by means of a facility to generate macros and menus.Processing requirements for GIS applications can be supported by using tools provided by relational database technology and by graphics packages. High-level language interfaces which can process dynamic statements and bind dynamic variables are needed to develop an efficient database interface module. A graphics segment facility is essential to provide editing functions and to maximize the use of the local processing power of graphics workstations in the graphics interface module. Further improvements in performance can be made by using the array fetch facility and linear keys for spatial searching.
Progress in technical database management systems offers alternative strategies for the design and implementation of databases for geographical information systems. Desirable extensions in the user data types and database management are reviewed. A prototype geographical database tool-kit, SIRO-DBMS, which provides some spatial data types and spatial access methods as external attachments to a kernel relational database management system, is described. An ability to fragment a large set of entities into several relations while retaining the ability to search the full set as a logical unit is provided. Implementation of the geometric data types is based on mapping the types of data into a set of attributes of the atomic types supported by the kernel and specifying the relational designs for the set of atomic attributes.
Geometric objects such as polygons, line segments, and points may have manifold relations among each other, i.e., order, adjacency, connectivity, etc., and may be stored in a database. For the design of the spatial data structure and in order to preserve consistency when manipulating the data, we propose a graph grammar approach. All consistent states are described by a structure graph, and the manipulation rules are given by productions where intersection problems as well as topologic properties have to be solved. By appropriately modeling the behavior of geographic data, consistency is preserved at all times. This eliminates the tedious case of recovering a geographic database after an inconsistency has been detected.
Geographic database systems are very demanding with respect to database systems, very much like engineering and other non-traditional DBMS applications. This paper describes a language called XSQL/2 which extends the facilities of SQL to provide better support for these applications in general, and geographic applications in particular.. Among the extensions, we find: the introduction of unique identifiers for tuples, the introduction of base (hierarchical) complex objects in a way compatible with the referential integrity feature of relational DBMS's, the possibility to define dynamically any complex object with a network structure and to navigate through such structures. The language also introduces abstract data types on scalar or structured columns, and on complex objects themselves.
The application of traditional database query languages, primarily the Structured Query Language SQL, for geographical information systems (GIS) and other non–standard database applications has been tried unsuccessfully; therefore, several extensions to the relational database query language SQL have been proposed to serve as a spatial query language. It is argued that the SQL framework is inappropriate for an interactive query language for a GIS and an extended SQL is at best a short term solution. Any spatial SQL dialect has a number of serious deficiencies, particularly the patches to incorporate the necessary spatial concepts into SQL.
An extension to the relational model is described in which domains can he arbitrarily defined as abstract data types. Operations on these data types include primitive operations, aggregates, and transformations. It is shown that these operations make the query language complete in the sense of Chandra and Harel. The system has been designed in such a way that new data types and their operations can be defined with a minimal amount of interaction with the database management system.
In new application areas of relational database systems, such as artificial intelligence, the join operator is used more extensively than in conventional applications. In this paper, we propose a simple data structure, called a join index, for improving the performance of joins in the context of complex queries. For most of the joins, updates to join indices incur very little overhead. Some properties of a join index are (i) its efficient use of memory and adaptiveness to parallel execution, (ii) its compatibility with other operations (including select and union), (iii) its support for abstract data type join predicates, (iv) its support for multirelation clustering, and (v) its use in representing directed graphs and in evaluating recursive queries. Finally, the analysis of the join algorithm using join indices shows its excellent performance.
Pictorial databases require efficient and direct spatial search based on the analog form of spatial objects and relationships instead of search based on some cumbersome alphanumeric encodings of the pictures. A description is given of PSQL, a query language that allows pictorial domains to be presented to the user in their analog form and allows him or her to do direct manipulation on the objects found on those domains. Direct spatial search and computation on the pictures is done using efficient data structures, R- and R** plus -trees (multidimensional B-trees), which are excellent devices for searching spatial objects and relationships found on pictures.
The R-tree, one of the most popular access methods for rectangles, is based on the heuristic optimization of the area of the enclosing rectangle in each inner node. By running numerous experiments in a standardized testbed under highly varying data, queries and operations, we were able to design the R*-tree which incorporates a combined optimization of area, margin and overlap of each enclosing rectangle in the directory. Using our standardized testbed in an exhaustive performance comparison, it turned out that the R*-tree clearly outperforms the existing R-tree variants. Guttman's linear and quadratic R-tree and Greene's variant of the R-tree. This superiority of the R*-tree holds for different types of queries and operations, such as map overlay, for both rectangles and multidimensional points in all experiments. From a practical point of view the R*-tree is very attractive because of the following two reasons 1 it efficiently supports point and spatial data at the same time and 2 its implementation cost is only slightly higher than that of other R-trees.
ESQL2 is an SQL2 upward-compatible database language that
integrates the essential concepts of relational, object-oriented, and
deductive databases. ESQL2's salient features are a rich and extendible
type system based on abstract data types (ADTs) implemented in various
programming languages, complex objects with object sharing by combining
generic ADTs and object identity, the capability of querying and
updating relations containing simple or complex objects using
SQL-compatible syntax and semantics, and a DATALOG-like deductive
capability provided as an extension of the SQL view mechanism. A
declarative semantics is proposed for ESQL2 retrieval statements using
F-Logic, which provides a solid basis for understanding the integration
of objects and relations
Pictorial databases require efficient and direct spatial search
based on the analog form of spatial objects and relationships instead of
search based on some cumbersome alphanumeric encodings of the pictures.
A description is given of PSQL, a query language that allows pictorial
domains to be presented to the user in their analog form and allows him
or her to do direct manipulation on the objects found on those domains.
Direct spatial search and computation on the pictures is done using
efficient data structures, R- and R+-trees (multidimensional
B-trees), which are excellent devices for searching spatial objects and
relationships found on pictures
While most current Geographical Information Systems (GIS) are 2D GIS, more and more application domains as geology, civil and military engineering, etc, need 3D GIS. The particularities and capabilities of a 3D GIS are outlined in this paper. Although 3D GIS are not much developped, some studies have already been done, especially in order to represent 3D data for geological or architectural applications. Such 3D models are generally based upon Computer-Aided Design (CAD) models. The use of 3D CAD models for representing 3D in GIS is discussed in the paper. As 3D GIS represent a 3D map, not only the surface of the terrain but also the entities set on the relief, e.g. buildings, have to be represented. The proposed 3D model for a GIS consists of representing 3D entities set on a Digital Terrain Model (DTM). These entities are represented with different approximation levels, the first two being used as index and processes accelerators and the last offering an efficient visualization suppo...
Utilisation de méthodes d'indexation spatiales pour optimiser les opérateurs spatiaux dans un SGBD Géo-Relationnel”, Mémoire ingénieur Cnam Paris 92
- Isabelle Artal
The GIS perspective on spatial and object oriented extensions to SQL”
- M Ashworth
GEQL: A Query Language for Geographic Information Systems”, Australian and New Zealand Association for the Advancement of Science Congress
- R Sacks-Davis
- K J Mcdonell
- B C Ooi
Overview of GIS Database Design ESRI” Arc News
- Don Chambers
Sabrina, a relational database system developed in a research environment
- G Gardarin
- M Jean-Noël
- B Kerhervé
- F Pasquer
- D Pastre
- E Simon
- P Valduriez
- Y Viémont
- L Verlaine
Using integrity constraints for checking consistency of spatial databases
- R Laurini
- F Milleret-Raffort
Méthodes d'accélération de la jointure spatiale à base de Pré-jointure et de topologie dans un SGBD Géo-Relationnel”, Mémoire ingénieur Cnam Paris 92
- Virginie Rascon
Thematic Map Modeling”, Symposium on the Design and Implementation of Large Spatial Databases
- M Scholl
- A Voisard
“fr Modélisation, représentation et gestion d'information géographique: une approche en relationnel étendu
- Benoît David
Temporal Aspects of Geographical Databases
- T S Yeh
- Y Viémont
La jointure spatiale
- Didier Chrétien
The Design of POSTGRES”, SIGMOD Conf
- M Stonebraker
- L A Rowe