ISSN:1082-4006    

DOI:10.1080/10824009909480507

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

In this paper, we report the results obtained from the application of digital photogrammetry and hyperspectral data analysis for forest inventory purposes. Our long term goal is to provide low-cost yet accurate estimates of as many important forest biophysical parameters as can be measured and inferred with airborne digital cameras. Accuracies of traditional multispectral image analysis algorithms of remotely sensed data are low. Traditional photo interpretation is error prone and expensive. We propose new image analysis strategies that make use of the 3D spatial morphological information from stereo images and the multispectral, texture and contextual information inherent in the imagery.

ISSN:1082-4006    

DOI:10.1080/10824009909480508

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Although national data sets are becoming readily available at low cost, scale usually limits their utility for planning and managing small municipalities. As a result, most communities are faced with the construction of their own municipal Geographic Information Systems (GIS), information systems that are critical in handling land-related activities where high accuracy is essential. Most small municipalities cannot afford to begin by commissioning a large scalecadastralmap and thus must opt for spatially questionable facsimiles where surveys showing administrative boundaries, property lines and street centerlines are suspect. The accuracy in these data can be enhanced and the results of great value to most city operations. We introduce a new method that applies theoretically based spatial decompositions to automate the generation of street centerlines from spatially corrected block and parcel data. This new centerline data base is a vast improvement over existing data bases for most municipalities.

ISSN:1082-4006    

DOI:10.1080/10824009909480509

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Major changes are about to engulf higher education. GIScience education is particularly exposed to these changes due to its dependence on technology and rootlessness with regards to traditional disciplines. Many important strategic activities and major projects involving the future of GIScience education have recently been conducted or initiated. Considering these activities and projects within this context of change in higher education helps ensure that they produce the most impact, address important existing and near-future demands, and satisfy the customers, our students.

ISSN:1082-4006    

DOI:10.1080/10824009909480510

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Five case studies are presented that demonstrate how metrics inferred from canopy photography can inform and validate the results from digital aerial photography and other remote sensing platforms. The forests measured include evergreen and deciduous canopies composed of both needle-leaved and broad-leaved tree species. Gap fractions of these forest canopies ranged from 3% to 22%. Significant fine-scale spatial autocorrelation of canopy structure was detected in two subalpine forests. In a conifer-hardwood forest, the canopy opening associated with the stream course still influenced understory light availability 45 m from the stream bank. In contrast, there was no correspondence between distance from the stream and canopy architecture in twoTsuga-dominated ravines. Forest stands classified as the same vegetation type and considered replicated sites in field experiments can have significant differences in some canopy metrics. The results from these ecological studies have direct relevance to the design of monitoring regimes based on remote sensing.

ISSN:1082-4006    

DOI:10.1080/10824009909480511

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Plant diversity of 94 subcounty regions in California was analyzed at species, genus, and family levels. The richness indices at the three taxonomic levels were related to the mean and standard deviation of the elevation of each region, and the statistical relationships are examined. Species-genus and species-family ratios, used as indicators of speciation capacity, are also related to the elevation mean and standard deviation. We found that all indices of richness and speciation capacity correlated positively with both variables of topography; an apparent distinction in the degree of correlation existed among taxonomic levels; the correlation coefficient decreased as the taxonomic level moves from species to genus to family. The speciation capacity correlated more closely with elevation mean and standard deviation than the richness indices did, suggesting that the topography affect species richness indirectly through influencing speciation capacity. In addition, the correlation coefficients for standard deviation of elevation were all greater than those of elevation mean, indicating that spatial variability of elevation was more directly related to plant diversity. The habitat heterogeneity hypothesis was modified to explain our result and discrepancies among results from various studies.

ISSN:1082-4006    

DOI:10.1080/10824009909480512

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

This study illustrates the application of range productivity models across a broad spatial scale. A series of relevant data layers for these range models were constructed using photo-interpretation and digital elevation models. A geographic information system was used to merge the data layers to evaluate total livestock carrying capacity for individual land parcels. This approach has application for county tax assessors interested in a scientific basis for appraising rural land values. The study was carried out in the foothills of California's San Joaquin Valley in response to policy concerns raised about the implementation of the California Land Conservation Act, a property tax system designed to conserve agricultural and open space values.

ISSN:1082-4006    

DOI:10.1080/10824009909480513

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Using hyperspectral reflectance data collected from six types of surface covers, we synthesized linear mixtures and used them to test the sensitivity of two linear unmixing algorithms to simulated additive noise. We found both algorithms were highly sensitive to noise. This may considerably limit their use in remote sensing.

ISSN:1082-4006    

DOI:10.1080/10824009909480514

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Geometric properties of a two-dimensional polygonal region are inherently useful in shape interpolation. Traditionally, shape interpolation begins with a collection of characteristic points that define the original polygons. The collection of characteristic points is confining in nature and does not deliver the desired solution at all times. This paper details an interpolation technique that takes a wholistic approach. The model draws on the principles and physical properties of potential fields. The model presented is adaptable to the three-dimensional space with little change in the computational complexity.

ISSN:1082-4006    

DOI:10.1080/10824009909480515

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor