ISSN:0143-1161    

DOI:10.1080/01431169408954314

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Hurricane Andrew rampaged across Florida and Louisiana causing businesses and homes to be lost and leaving thousands of people homeless. This storm was a category 4 on the Saffir-Simpson scale and generated winds of 145 miles per hour (65ms-1) with gusts exceeding 175 miles per hour (78ms-1). Billions of dollars were needed for repairs, shelters, and public utilities. Federal organizations like the National Guard and large corporations provided communities with shelter, food and clothing. Hurricane Andrew. a storm Americans will never forget.

ISSN:0143-1161    

DOI:10.1080/01431169408954315

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

AHVRR Channel 3 data have been used widely for forest fire detection and mapping. However, little attention has been paid to the use of these data for daily fire growth monitoring. A simple method for fire growth mapping using channel 3 data is presented. An 18000 hectare forest fire affecting the Mediterranean coast of Spain is used as a case study. Discrimination of burned area was performed on every image after multitemporal registration. A thermal threshold was established to mask out fire pixels in both diurnal and nocturnal images. GIS overlay techniques were used lo obtain a synthesis map of the daily evolution of the fire. This product can generate valuable input for fire behaviour programmes to improve our understanding of the factors affecting fire spread and fire severity.

ISSN:0143-1161    

DOI:10.1080/01431169408954316

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The evaluation of the influence of topography on landscape radiation temperature distribution is carried out by statistical processing of digital models of elevation, gradient, aspect, horizontal, vertical and mean landsurface curvatures and the infrared thermal scene generated by the Thermovision 880 system. Significant linear correlation coefficients between the landscape radiation temperature and elevation, slope, aspect, vertical and mean landsurface curvatures are determined, being —0-57, 0 38, 0-26, 015, 013, respectively. The equation of the topography influence on the distribution of the landscape radiation temperature is defined.

ISSN:0143-1161    

DOI:10.1080/01431169408954317

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The Rann of Kutch, Gujarat is the only habitat for one of the endangered sub-species of the Asiatic wild ass (Equus hemionus khur) and most of the population survives in the Wild Ass Sanctuary in Little Rann of Kutch. The area is a saline desert with extremely sparse cover of vegetation. In the past, the habitat supported a thriving population of wild asses. However, due to extensive changes in the land-use around the Rann of Kutch, there has been an increase in the conflict of interests between man and the wild ass. The present paper seeks to analyse the situation with respect to changes in land-use, vegetation cover and salt cultivation to plan proper habitat management inside the sanctuary to mitigate the problem of crop predation by the wild ass through the use of high resolution satellite data.

ISSN:0143-1161    

DOI:10.1080/01431169408954318

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Development of highway alignment demands the planner to conduct map study, preliminary, reconnaissance and direct surveys. This takes much time and energy in preparing final drawings. Remote sensing acts as a very powerful tool to finalise the final alignment within less time and energy. The data-like soil type, landuse, terrain and topographical features are collected from imagery and census data were used in this analysis to identify the flight line alignment. In this work techniques like trip distribution model and trip polygon method are approached in finalising flight line alignment. Apart from this the ground line alignment is developed with the above data and the difference in cost is estimated.

ISSN:0143-1161    

DOI:10.1080/01431169408954319

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A large area of barren salt-affected soils has been reclaimed in recent years in the Ganges Plains or Uttar Pradesh, India, Increased canal irrigation in the area, on the other hand, is also leading to salinization of new areas. A study was conducted using aerial photographs and Landsat Thematic Mapper (TM) data to monitor change in the status of salt-affected soils in the Kanpur district of Uttar Pradesh. Old survey maps prepared using ground methods in 1956, showing large salt-affected soil blocks of more than 80 ha, were used as a basis for comparison. These maps were compared with the maps prepared using aerial photographs of 1972 and Landsat TM images of 1986. Aerial photographs on a 1:40 000 scale and standard Landsat TM false colour composite (FCC) image on 1:50000 scale provided a minimum delineation of 2 ha size, which was considered sufficient for change detection in the present case. The average increase in cultivation due to reclamation within the salt-affected soil blocks during 1956-86 was found to be 22 per cent. This increase was also corroborated by the increase in the rice area during the above period in the district since these soils are used mainly for rice cultivation. During 1972-86, an increase in the extent of salt-affected soils on the periphery of large blocks was also observed, which was limited to 3 per cent.

ISSN:0143-1161    

DOI:10.1080/01431169408954320

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

As a test of the sensitivity of Landsat Thematic Mapper (TM) data to evaluate small-scale environmental change and post-drought recovery, a time series of TM images of the small, well-mapped region around Tombouctou, Mali was analysed for change for the interval 1986-1988. Actual increases in vegetation measured during field work differed for specific landforms, ranging from 5 per cent on floodplain silts to a 40 per cent increase in ephemeral grass cover on stable dunes. This region is part of the Saharan-Sahelian fringe, where severe drought and environmental degradation occurred between 1976 and 1985. Reflectance curves derived from the TM images for six specific landform units between March 1986 and March 1988 show that seasonal reflectance changes are statistically significant, and that overall reflectance decreased over the study interval. Dunes, abandoned wadis and inactive floodplain areas near the Niger river show vegetation regrowth, while active floodplain and densely-vegetated distributary channels showed little change. Albedo proved to be a reasonable simple indicator of both seasonal change and change over the term of study. Neither the Normalized Difference Vegetation Index (NDVI), the Soil-Adjusted Vegetation Index (SAVI) nor the Leaf Vegetation Index (VL) produced results consistent with field observation. Normalized reflectances and albedo both show appropriate seasonal trends and an overall trend towards increased vegetation that is consistent with field observations over the study interval.

ISSN:0143-1161    

DOI:10.1080/01431169408954321

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Global Vegetation Index (GVI) data from the Advanced Very High Resolution Radiometer (AVHRR) was used to identify macro-scale vegetation/ land cover regions in the former Soviet Union (FSU). These regions are a better representation of surface vegetation and land cover than can be obtained from existing thematic maps of the FSU. Image classes were identified through cluster analysis using the ISODATA clustering algorithm and a maximum likelihood classifier. Qualitative analysis of the image variants produced with different input parameters indicated that an image with 42 classes best represented significant details in vegetation and land cover patterns without producing uninterpretable levels of details that represent artefacts of the clustering algorithm. Initial identification of image classes has been made by considering the weight of evidence provided by quantitative and qualitative analysis of existing maps, analytical tools from class statistics, ancillary data from a variety of sources and expert assessment by Russian scientists with extensive field experience in the FSU. Overall, this method of image classification using GVI data appears to describe accurately regions with similar vegetation and hind cover across the FSU. Some questions regarding the identification of wetlands and potential problems with classification in the Russian high arctic are discussed. The products of this research will help improve carbon budget estimates of the FSU by providing accurate delineation and definition of carbon quantifiable regions.

ISSN:0143-1161    

DOI:10.1080/01431169408954322

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

This paper demonstrates a methodology for relating objective vegetation classifications to spectral classifications in order to map variation in species composition within natural vegetation. Landsat MSS data was used to map spinifex-dominated vegetation units for an island conservation reserve and oil production field on the north-western shelf of Western Australia. A significant relationship was established between an agglomerative hierarchical classification of ground samples, characterized by percentage cover of plant species and physical cover components, and a similar classification of spectral means for sample pixels. Assignment of spectral means to mapping classes was guided by both ground and spectral sample clustering. The strong relationship between the spectral classification and vegetation groups meant that cover classes mapped on the basis of spectral properties could be characterized by quantitative ground data meaningful to vegetation ecology. The resultant groups were differentiated largely on the basis of percentage cover of the three major spinifex species and the proportion of plant litter and exposed soil and surface rock. The study confirms the utility of ground cover as a quantitative variable for developing relationships with spectral classifications, and demonstrates a methodology which may have a wider application for mapping natural vegetation communities.

ISSN:0143-1161    

DOI:10.1080/01431169408954323

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor