摘要:

Although the acquisition and maintenance of spatial data is very costly and time consuming very often the same objects of the real world are captured in many different data models, at different acquisition times, with different quality characteristics or at different scales. This situation will become intensified when more and more digital spatial data are offered by using internet technologies. Integration methods are needed to take advantage of the characteristics of more than one data set. These advantages could be, for example, new applications for which the data models had not been originally designed, higher reusability, improvement of the quality, or cost minimization of data acquisition. In this paper a relational matching approach for integration of spatial data from different sources is introduced. The research work was performed on street centrelines which were captured in different data models. The approach is based on statistical investigations between the data of two data models, and can be used in the same way for other data models. The matching problem is mapped onto a communication system, and measures, derived from information theory, are used to find an optimal solution. These measures can also be used for calculating local and global quality characteristics of the matching result.

ISSN:1365-8816    

DOI:10.1080/136588199241157

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Unlike most of the current object-oriented geographical information systems (OOGISs) whose designs are based on the traditional spatial conceptual model emphasizing the processing of geometric features, the concept-based OOGIS proposed in this paper provides a spatial conceptual model which comprises rich spatial semantics fundamental to spatial analysis, and an object-oriented data model (OODM) which provides an appropriate and effective representation of the spatial conceptual model for efficient database management. By structuring the cognition of space through three interrelated hierarchies: namely the spatial conceptual hierarchy, the entity hierarchy and the feature hierarchy, the generic concept-based OOGIS renders an appropriate framework for the scientific investigation of space and the design of an efficient object-oriented database management system. In addition to its generic nature, the proposed OOGIS is in line withour commonsense conceptualization of space. Furthermore, it can entertain multiple-representations, and can facilitate data integration and generalization. The present investigation thus advances an effective way for OOGIS research in general and design in particular.

ISSN:1365-8816    

DOI:10.1080/136588199241166

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

This paper describes a new non-parametric model to estimate space use. We test the similarity in space use patterns between an artificially generated utilization distribution (Seaman- UD) and the model estimates for five different sample sizes. Three different test statistics (Kappa,gamma,Tc) reveal a high similarity between the estimates and the Seaman-UD. The tests also show that, beyond a certain threshold value, larger sample sizes do not return significantly better results. W e further demonstrate that the Thiessen model delineated areas of intensive use more effectively in a home range than Kernel estimators. UD estimation uses AML (ArcInfo Macro Language), thus facilitating overlay operations with habitat information stored in the same ArcInfo GIS environment.

ISSN:1365-8816    

DOI:10.1080/136588199241175

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Political decisions concerning the environment are frequently based on aggregated versions of scientific results, obtained by post-processing. Decision makers generally use such results, without the luxury of questioning them. GIS experts often act as intermediary between decision makers and scientists. To support that role, guidelines are needed to gain insight into the aggregation issues involved in presenting spatial information. This paper provides such guidelines. The procedure focuses on aggregation prior to modelling (approach A) or afterwards (approach B) and considers two major aggregation techniques (mean and worst case). Some simple indicators are used to quantify the differences between maps. The procedure is tested with an actual case of agricultural pesticide risk, which demonstrates its use. It proved very helpful to improve on the insight needed. It showed the complexity of the issue and the sensitivity to level and method of aggregation, as well as to classification and model type.

ISSN:1365-8816    

DOI:10.1080/136588199241184

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

ISSN:1365-8816    

DOI:10.1080/136588199241193

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor