Results 1  10
of
46
Multidimensional Access Methods
, 1998
"... Search operations in databases require special support at the physical level. This is true for conventional databases as well as spatial databases, where typical search operations include the point query (find all objects that contain a given search point) and the region query (find all objects that ..."
Abstract

Cited by 563 (3 self)
 Add to MetaCart
Search operations in databases require special support at the physical level. This is true for conventional databases as well as spatial databases, where typical search operations include the point query (find all objects that contain a given search point) and the region query (find all objects that overlap a given search region). More
A Foundation for Representing and Querying Moving Objects
, 2000
"... Spatiotemporal databases deal with geometries changing over time. The goal of our work is to provide a DBMS data model and query language capable of handling such timedependent geometries, including those changing continuously which describe moving objects. Two fundamental abstractions are moving ..."
Abstract

Cited by 152 (35 self)
 Add to MetaCart
Spatiotemporal databases deal with geometries changing over time. The goal of our work is to provide a DBMS data model and query language capable of handling such timedependent geometries, including those changing continuously which describe moving objects. Two fundamental abstractions are moving point and moving region, describing objects for which only the timedependent position, or position and extent, are of interest, respectively. We propose to represent such timedependent geometries as attribute data types with suitable operations, that is, to provide an abstract data type extension to a DBMS data model and query language. This paper presents a design of such a system of abstract data types. It turns out that besides the main types of interest, moving point and moving region, a relatively large number of auxiliary data types is needed. For example, one needs a line type to represent the projection of a moving point into the plane, or a "moving real" to represent the timedependent distance of two moving points. It then becomes crucial to achieve (i) orthogonality in the design of the type system, i.e., type constructors can be applied uniformly, (ii) genericity and consistency of operations, i.e., operations range over as many types as possible and behave consistently, and (iii) closure and consistency between structure and operations of nontemporal and related temporal types. Satisfying these goals leads to a simple and expressive system of abstract data types that may be integrated into a query language to yield apowerful language for querying spatiotemporal data, including moving objects. The paper formally defines the types and operations, offers detailed insight into the considerations that went into the design, and exempli es the use of the abstract data types using SQL. The paper o ers a precise and conceptually clean foundation for implementing a spatiotemporal DBMS extension.
SpatioTemporal Data Types: An Approach to Modeling and Querying Moving Objects in Databases
, 1999
"... Spatiotemporal databases deal with geometries changing over time. In general, geometries cannot only change in discrete steps, but continuously, and we are talking about moving objects. If only the position in space of an object is relevant, then moving point is a basic abstraction; if also the ext ..."
Abstract

Cited by 140 (37 self)
 Add to MetaCart
Spatiotemporal databases deal with geometries changing over time. In general, geometries cannot only change in discrete steps, but continuously, and we are talking about moving objects. If only the position in space of an object is relevant, then moving point is a basic abstraction; if also the extent is of interest, then the moving region abstraction captures moving as well as growing or shrinking regions. We propose a new line of research where moving points and moving regions are viewed as threedimensional (2D space + time) or higherdimensional entities whose structure and behavior is captured by modeling them as abstract data types. Such types can be integrated as base (attribute) data types into relational, objectoriented, or other DBMS data models; they can be implemented as data blades, cartridges, etc. for extensible DBMSs. We expect these spatiotemporal data types to play a similarly fundamental role for spatiotemporal databases as spatial data types have played for sp...
The DEDALE System for Complex Spatial Queries
, 1998
"... This paper presents dedale, a spatial database system intended to overcome some limitations of current systems by providing an abstract and nonspecialized data model and query language for the representation and manipulation of spatial objects. dedale relies on a logical model based on linear const ..."
Abstract

Cited by 75 (9 self)
 Add to MetaCart
This paper presents dedale, a spatial database system intended to overcome some limitations of current systems by providing an abstract and nonspecialized data model and query language for the representation and manipulation of spatial objects. dedale relies on a logical model based on linear constraints, which generalizes the constraint database model of [KKR90]. While in the classical constraint model, spatial data is always decomposed into its convex components, in dedale holes are allowed to fit the need of practical applications. The logical representation of spatial data although slightly more costly in memory, has the advantage of simplifying the algorithms. dedale relies on nested relations, in which all sorts of data (thematic, spatial, etc.) are stored in a uniform fashion. This new data model supports declarative query languages, which allow an intuitive and efficient manipulation of spatial objects. Their formal foundation constitutes a basis for practical query optimizati...
Comparison of approximations of complex objects used for approximationbased query processing in spatial database systems
, 1993
"... The management of geometric objects is a prime example of an application where efficiency is the bottleneck; this bottleneck cannot be eliminated without using suitable access structures. The most popular approach for handling complex spatial objects in spatial access methods is to use their minimum ..."
Abstract

Cited by 57 (11 self)
 Add to MetaCart
The management of geometric objects is a prime example of an application where efficiency is the bottleneck; this bottleneck cannot be eliminated without using suitable access structures. The most popular approach for handling complex spatial objects in spatial access methods is to use their minimum bounding boxes as a geometric key. Obviously, the rough approximation by bounding boxes provides a fast but inaccurate filter for the set of answers to a query. In order to speed up the query processing by a better approximation quality, we investigate six different types of approximations. Depending on the complexity of the objects and the type of queries, the approximations 5corner, ellipse and rotated bounding box clearly outperform the bounding box. An important ingredient of our approach is to organize these approximations in efficient spatial access
SpatioTemporal Predicates
 IEEE Transactions on Knowledge and Data Engineering
, 1999
"... AbstractÐThis paper investigates temporal changes of topological relationships and thereby integrates two important research areas: First, twodimensional topological relationships that have been investigated quite intensively and, second, the change of spatial information over time. We investigate ..."
Abstract

Cited by 47 (16 self)
 Add to MetaCart
AbstractÐThis paper investigates temporal changes of topological relationships and thereby integrates two important research areas: First, twodimensional topological relationships that have been investigated quite intensively and, second, the change of spatial information over time. We investigate spatiotemporal predicates, which describe developments of wellknown spatial topological relationships. A framework is developed in which spatiotemporal predicates can be obtained by temporal aggregation of elementary spatial predicates and sequential composition. We compare our framework with two other possible approaches: one is based on the observation that spatiotemporal objects correspond to threedimensional spatial objects for which existing topological predicates can be exploited. The other approach is to consider possible transitions between spatial configurations. These considerations help to identify a canonical set of spatiotemporal predicates. Index TermsÐTime in geographic information, spatiotemporal data types, representation of spatiotemporal objects, changes of spatial predicates, developments of spatial objects. 1
Spatial data types
"... Data types are a well known concept in computer science (for example, in programming languages or in database systems). A data type defines a set of homogeneous values and the allowable operations on those values. An example is a type integer representing the set of 32bit integers and including ope ..."
Abstract

Cited by 45 (18 self)
 Add to MetaCart
Data types are a well known concept in computer science (for example, in programming languages or in database systems). A data type defines a set of homogeneous values and the allowable operations on those values. An example is a type integer representing the set of 32bit integers and including operations such as addition, subtraction, and multiplication that can be performed on integers. Spatial data types or geometric data types provide a fundamental abstraction for modeling the geometric structure of objects in space as well as their relationships, properties, and operations. They are of particular interest in spatial databases [5, 8, 13] and Geographical Information Systems [14]. One speaks of spatial objects as values of spatial data types. Examples are twodimensional data types for points (for example, representing the locations of lighthouses in the U.S.), lines (for example, describing the ramifications of the Nile Delta), regions (for example, depicting airpolluted zones), spatial networks (for example, representing the routes of the Metro in New York), and spatial partitions (for example, describing the 50 states of the U.S. and their exclusively given topological relationships of adjacency or disjointedness) as well as threedimensional data types for surfaces (for example, modeling the shape of landscapes) or volumes (for example, representing urban areas). Operations on spatial data types include spatial operations like the geometric intersection, union, and difference of spatial objects, numerical operations like the length of a line or the area of a region, topological relationships checking the relative position of spatial objects to each other
RealmBased Spatial Data Types: The ROSE Algebra
 VLDB JOURNAL
, 1995
"... Spatial data types or algebras for database systems should (1) be fully general, that is, closed under set operations, (2) have formally defined semantics, (3) be defined in terms of finite representations available in computers, (4) offer facilities to enforce geometric consistency of related spat ..."
Abstract

Cited by 42 (3 self)
 Add to MetaCart
Spatial data types or algebras for database systems should (1) be fully general, that is, closed under set operations, (2) have formally defined semantics, (3) be defined in terms of finite representations available in computers, (4) offer facilities to enforce geometric consistency of related spatial objects, and (5) be independent of a particular DBMS data model, but cooperate with any. We present an algebra that uses realms as geometric domains underlying spatial data types. A realm, as a general database concept, is a finite, dynamic, userdefined structure underlying one or more system data types. Problems of numerical robustness and topological correctness are solved within and below the realm layer so that spatial algebras defined above a realm have very nice algebraic properties. Realms also interact with a DMBS to enforce geometric consistency on object creation or update. The ROSE algebra is defined on top of realms and offers general types to represent point, line, and region features, together with a comprehensive set of operations. It is described within a polymorphic type system and interacts with a DMBS data model and query language through an abstract object model interface. An example integration of ROSE into the objectoriented data model 02 and its query language is presented.
Vague regions
 5TH INT. SYMP. ON ADVANCES IN SPATIAL DATABASES, LNCS 1262
, 1997
"... In many geographical applications there is a need to model spatial phenomena not simply by sharp objects but rather through indeterminate or vague concepts. To support such applications we present a model of vague regions which covers and extends previous approaches. The formal framework is based on ..."
Abstract

Cited by 42 (20 self)
 Add to MetaCart
In many geographical applications there is a need to model spatial phenomena not simply by sharp objects but rather through indeterminate or vague concepts. To support such applications we present a model of vague regions which covers and extends previous approaches. The formal framework is based on a general exact model of spatial data types. On the one hand, this simplifies the definition of the vague model since we can build upon already existing theory of spatial data types. On the other hand, this approach facilitates the migration from exact to vague models. Moreover, exact spatial data types are subsumed as a special case of the presented vague concepts. We present examples and show how they are represented within our framework. We give a formal definition of basic operations and predicates which particularly allow a more finegrained investigation of spatial situations than in the pure exact case. We also demonstrate the integration of the presented concepts into an SQLlike query language.