摘要:

The advancement of GIS data models to allow the effective utilization of very large heterogeneous geographic databases requires a new approach that incorporates models of human cognition. The ultimate goal is to provide a cooperative human-computer environment for spatial analysis. We describe the pyramid framework as an example of this new approach within the context of some important aspects of how humans conceptually store spatial information. The proposed framework provides the means to create multiple structural interpretations of observed geographic data and the ability to build knowledge hierarchies through the application of data mining and other statistical techniques.

ISSN:1365-8816    

DOI:10.1080/136588100415710

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

This paper describes how a standard GIS package can be used to convert large-scale vector digital data (point, line and annotation features) into polygons using standardised and replicable methods. Building area, garden and land use polygons are all derived from such data (Ordnance Survey LandLine.Plus). These entities are then combined with further sources of digital data to derive more refined information such as property types. Finally, complex DEMs are developed for use in visibility studies. The variables calculated are subsequently employed in a property valuation study where many are found to be significant determinants of property price. The main exception is variables relating to viewsheds, although it is argued that this does not invalidate the techniques used in their deviation but highlights the difficulties involved in modelling a large number of variables in a property price analysis.

ISSN:1365-8816    

DOI:10.1080/136588100415729

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The integration of GIS and spatial statistical analysis can occur in two different ways: embedding spatial statistical analysis into a GIS environment, or embedding selected GIS functions into a spatial statistical analysis environment. Attention has been given almost exclusively to the former in the past. This paper argues that the latter deserves more attention, especially with the rapid development of embeddable GIS component technology. However, because current statistical software packages have not yet provided the environment into which GIS components can be embedded, we explore the possibility of integrating GIS components and spatial statistical analysis in a current proprietary Database Management System (DBMS: Microsoft Access), which can be easily extended to incorporate statistical analysis capabilities. A conceptual framework for this integration is outlined, an interactive spatial statistical analysis module is presented, and an example is used to illustrate the advantage of this module.

ISSN:1365-8816    

DOI:10.1080/136588100415738

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

This paper presents map analysis of digital elevation models for glaciological applications. The approach has been to combine spatial information describing the geometry of the glaciers with physical models of glaciological processes and to adjust empirical parameters to give a best fit with field observations. This applies to description of the basal shear stress and the resulting flow due to deformation of the ice. The outputs display spatial distributions, which can be adjusted to field observations through flexible routines of averaging the geographical information. Further, this approach is applied to description of the potential driving water along the bed, defined by the basal topography of the glacier and a model assuming that the basal water pressure is related to the thickness of the ice. The results produce predictions of the location of subglacial waterways and their drainage basins, which can be adjusted to field observations by choice of an empirical parameter, giving the basal water pressure as a fraction of the ice overburden pressure. A routine is presented that integrates the meltwater contribution downglacier to the various river outlets, given the glacier surface ablation.

ISSN:1365-8816    

DOI:10.1080/136588100415747

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Through the integration of SPOT HRV, biophysical and socioeconomic information, the study identified population carrying capacities and their vulnerability to land degradation. Land use intensification on the landscapes was quantified into expansion, early and late phases based on the Ruthenberg index calculated using a biennial series of SPOT images for the period 1986-96. Subsequently, farmland dynamic on different landscapes was calculated while observed patterns were linked with agricultural intensification and population carrying capacity. Results show a pattern of agricultural land degradation due to increasing pressure of population and agricultural intensification within a system characterised by little or no use of inputs. Fifty-six percent of the study area supports a population density higher than the carrying capacity (≤ 15 pers/km-2). Sixty-three percent of the study area is under early to late phases of agricultural intensification. Between 1986-96, cultivation declined 2-3% annually on landscapes with Low risk of degradation but increased by 1-2% on those with Average/Extreme risks. This emphasises the process of land abandonment as farmers move on to cultivating marginal lands despite above normal seasonal rainfalls observed during most of the period. By 1996, cultivation tended to include fields much farther away from the vicinity of villages, compared with 10 years earlier. Furthermore, by 1996, farmlands in the zones of late intensification declined from 12 to 4% and increased from 6 to 11% in the zone under the expansion phase. Indicating that by 1996 substantial amount of the land area required increasing lengths of fallowing. The spatial GIS modelling approach allowed not only identification of zones but synthesis of the observed pattern of landscape degradation. The paper highlights the need for combining remote sensing, biophysical and socio-economic data in environmental degradation studies in developing countries with their poor data availability. The role of developing countries scientists is stressed in taking the forefront to tackle environmental problems, which affect their region. The paper calls for increased co-operation between these scientists and regional and international data providers to overcome data availability problems and pave the way for better local and regional studies on environmental degradation.

ISSN:1365-8816    

DOI:10.1080/136588100415756

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

ISSN:1365-8816    

DOI:10.1080/136588100415765

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor