A Unified Approach for Spatial Data Query

2005

Cartography, 2003

Many geographical databases have been developed by different programs and applications, but data acquisition and data sharing are still a big problem because no interoperability exists among these different databases. This study presents a GML (Geography Markup Language) approach to build a geographical database in order to enable interoperability. As an open, non-proprietary industry standard, GML overcomes the problems of current GIS software proprietary data models and database structures. Compared with other standards, such as Geographic Data File (GDF) and Spatial Data Transfer Standard (SDTS), GML approach has the advantage of enabling on-line data exchange. GML holds promise in providing a standard way to share and use the existing spatial data over the Web. A GML-based interoperable geographical database for the conservation of the Stone Forest Landscape is implemented as a case study. It shows that the public can access and use the GML-based spatial database through a user-friendly interface and that GML can deliver high quality vector data on the Web.

Proceedings of SOUTHEASTCON '96, 2000

A practical Geographic Information System necessitates the manipulation of an extensive amount of spatially referenced data. From the retrieval process to the display function, the burden on both the hardware and software of the target system to process the data in a time restrictive manner is considerable and creates the impetus for the development of new techniques in data handling. The methods must ensure that the representation to the user is believable, useful, versatile and accomplishes the understood tasks of a GIs: to represent graphically or pictorially, either statically or dynamically, in a determinate span of time, what would be exhausting if not impossible to accomplish textually. A key facet in the achievement of these goals is how data are represented on a virtual storage medium and the manner in which these data are retrieved. The systematic coordination between the data access method and the application that processes a highly detailed visual representation must be time-tolerant for the user when the data are time relative. The challenge is to implement these ideals with the technology most prevalent to current potential users (research facilities, libraries, municipalities), with serious consideration towards all users with a desktop computer.

1988

International Journal of Geographical Information Science, 1998

This paper investigates the problems that arise when application requirements command that autonomous spatial databases be integrated into a federated one. The paper focuses on the most critical issues raised by the integration of databases of different scales. A short presentation of approaches to interoperability and of the main steps composing the integration process is given first. Next, a general format is proposed for precisely defining correspondences between objects of two databases. The format can deal with a wide range of discrepancies in GIS data. Last, a solution is presented for aggregation conflicts which arise when one object of one database corresponds to a set of objects in the other database, a very frequent case when the databases are of different scales. The method is applied to excerpts of real cartographic databases.

1990

All systems for managing data face common problems such as backup, recovery, auditing, security, data integrity and concurrent update. Other challenges include the ability to share data easily between applications and to distribute data across several computers, while continuing to manage the problems already mentioned. Geographic information systems are no exception, and need to tackle all these issues. Standard relational database management systems provide many features to help solve the issues mentioned so far. This article describes how the IBM geoManager product approaches these issues by storing all its geographic data in a standard relational database product in order to take advantage of such features. Areas in which standard relational database functions need to be extended are highlighted, and the way in which geoManager does this is explained. The performance implications of storing all data in the relational database are discussed. An important distinction is made between the storage and management of geographic data and the manipulation and analysis of geographic data, which needs to be made when considering the applicability of relational database technology to GIS.

1990

The design of an integrated system is described for combining spatial and nonspatial attribute data to allow fast query handling. By fast it is meant that search queries can be executed in logarithmic time. Nonspatial attribute data is managed by standard database techniques. Efficient and robust spatial data structures are used to store spatial information. In addition to the standard access methods usually provided for accessing attribute data (i.e. through the data base management system), data can also be accessed through the spatial data structures in a homogeneous way that is transparent to the user. The design makes use of an SQL-like interface. The SQL query language is extended to provide efficient access methods to spatial structures, and to match functional and efficiency requirements desired from a combination of spatial and nonspatial information. The simplicity of SQL helps to clarify the design approach. However, other interfaces can be used with minor modifications.

The dynamic environment of SDIs and the involvement of diverse spatial data providers present uncertainty for involving organizations. This pushes organizations to focus on cooperative data sharing relationships to deliver their objectives. Spatial data sharing provides transactions in which individuals, governments and businesses obtain access to spatial data and services from other stakeholders. However, spatial data sharing goes beyond simple data exchange and requires the provision of usable datasets. It is specifically important at multi-national level and Global SDI (GSDI).

Computers & Geosciences, 1992

All systems for managing data face common problems such as backup, recovery, auditing, security, data integrity and concurrent update. Other challenges include the ability to share data easily between applications and to distribute data across several computers, while continuing to manage the problems already mentioned. Geographic information systems are no exception, and need to tackle all these issues. Standard relational database management systems provide many features to help solve the issues mentioned so far. This article describes how the IBM geoManager product approaches these issues by storing all its geographic data in a standard relational database product in order to take advantage of such features. Areas in which standard relational database functions need to be extended are highlighted, and the way in which geoManager does this is explained. The performance implications of storing all data in the relational database are discussed. An important distinction is made between the storage and management of geographic data and the manipulation and analysis of geographic data, which needs to be made when considering the applicability of relational database technology to GIS.

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 on listing open problems.