摘要:

Presettlement forest types were mapped as fuzzy sets from point data representing trees contained in General Land Office survey notes (circa 1850) for Chippewa County, Michigan. The resulting representation agreed with a polygon map of the same forest types at 66% of the locations (represented as grid cells) in the county. Boundary vagueness was defined in relation to the slope of a linear function fitted to the negative relation between entropy offorest types and distance to polygon boundaries. The similarity between forest type compositions (i.e. classification ambiguity) was shown to account for 55% of the variation in boundary vagueness.

ISSN:1365-8816    

DOI:10.1080/136588198241914

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

This paper describes a newly developed statistical approach for modelling positional error of geometric features in GIS. The generic statistical models for N-dimensional features are firstly derived. The models for one- and twodimensional features are then developed as the specific cases of the generic models. In each dimension, the GIS features are classified as points, line segments and line features. Because of the errors, features stored in GIS may not correspond with their actual location in the real world. The true location of a GIS feature is only known within a certain area around the represented location in GIS. This newly developed approach can be used to provide a statistical description of such areas. For one-, two- and N-dimensional GIS features, they are defined as confidence intervals, confidence regions and confidence spaces respectively. The areas are related to the positional errors of the composite points of the features and to the predefined confidence level. The models are derived based on the assumptions that the errors of the composite points are independent and follow multi-dimensional normal distributions.

ISSN:1365-8816    

DOI:10.1080/136588198241923

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Performing data manipulations on maps that possess error as a result of the process of data collection leads to error propagation. The errors that are present in maps are modified by such operations in ways that may undermine the purposeofanalysisand lead to increased uncertainty in thevalidity ofthe conclusions that are drawn. This paper analyses how source map error propagates as a result of overlay operations. Geman and Geman's corruption model for individual source map error is used for the analysis which allows for attribute measurement error and location error that can then interact with the (true) source map geography. This paper reports theoretical results on the univariate overlay problem and then extends these results through simulation. Throughout a set of source maps and error processes are used with specified properties in order to examine in detail the interactions that can take place between the different elements of the source map structure and the error process. The paper uses ANOVA methods to quantify the contribution made by different components of the map and the measurement process to spatial (join count) and non-spatial (proportion of misclassified pixels and the Kappa index) descriptors of error. The paper concludes with a discussion of the usefulness of these results for managing error in spatial databases and for the development of automated uncertainty reporting.

ISSN:1365-8816    

DOI:10.1080/136588198241932

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

There has been worldwide concern for sustainable development especially after the 1992's Rio's UN Conference on Environment and Development. Rapid encroachment of urban development on valuable agricultural land will have great influence on whether sustainable development can be achieved. A sustainable land development model is developed using GIS in an attempt to control urban sprawl under rapid rural urbanization. The objective of the model is to ensure that equity between generations and efficiency in land use can be achieved in land development so that development can be sustained in the future. The model is used to study the impacts of agricultural land loss in Dongguan in 1988-93, a rapidly growing area in the Pearl River Delta of China. The impact of unplanned urban growth is evaluated by comparing the actual development with optimal development derived from the sustainable land development model. Land use problems are identified in both spatial and time dimensions as some land conversions are found to occur at the ‘wrong' time and locations. Future land development which can meet the objective of sustainable development is proposed using the model. By testing different development scenarios and land consumption parameters, planners and government officials can use the model as a decision support system for sustainable land development in areas in the world that are under great pressure of rapid urban growth.

ISSN:1365-8816    

DOI:10.1080/136588198241941

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

ISSN:1365-8816    

DOI:10.1080/136588198241950

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

As always, compiling a fully refereed academic journal requires the voluntary co-operation of a huge number of referees. In the following list, all the 284 people who have contributed with their time to the refereeing process in the 12 months from September 1996-September 1997 are listed. Indeed, a number of those named have been asked to review more than once. On behalf of the authors (accepted, published and rejected), the publisher and the editors, I would like to express my sincere thanks to you all. Your contribution ensures the quality of the journal. I would also like to thank Jill Fisher for her help and patience in compiling the list.

ISSN:1365-8816    

DOI:10.1080/136588198241969

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor