ISSN:0143-1161    

DOI:10.1080/01431169608948727

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A Portable Infrared Mineral Analyzer II (PIMA II) field spectrometer was used to measure infrared reflectance spectra (1·3-2·5 μm) of split drill core at 1 cm intervals in both the along-core and cross-core directions. These data were formatted into an image cube similar to that acquired by an imaging spectrometer with 600 spectral channels, and multi-spectral and hyperspectral analysis techniques were used for analysis. Colour images and enhancements provided visual displays of the spectral information, while real-time digital extraction of individual spectra allowed identification of minerals. Absorption band-depth mapping and spectral classification were used to map the spatial distribution of specific minerals in the core. Linear spectral unmixing provided estimated mineral abundances. Analysis results demonstrate that multi-spectral and hyperspectral image analysis methods can be used to produce detailed mineralogical maps of drill core. They suggest that the concepts and analytical techniques developed for analysis of hyperspectral image data can be applied to field and laboratory spectra in a variety of disciplines, and raise the question of the use of hyperspectral scanners in the laboratory.

ISSN:0143-1161    

DOI:10.1080/01431169608948728

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The Ronda peridotite massif and bordering marbles (Málaga province, southern Spain) are studied in Geophysical Environmental Research 63-channel Imaging Spectrometer data (GERIS). Reflectance spectra of weathered rock and soil samples form the basis for selecting endmembers for spectral unmixing of the GERIS data and mineral mapping by means of spectral angle mapping. Six spectral endmembers model the continuum reflectance of each pixel: three soil types (aperidotitesoil, alimestonesoil, and aspectrally quenchedsoil), green vegetation (and grass), senescent vegetation, and decayed vegetation. The spatial distribution of the soil endmembers shows that the spectrally quenched soil is restricted to an area near to the mylonitized contact zone between the marbles and the peridotites. Mineral mapping from GERIS data confirms the known metamorphic zonation of the Ronda peridotite body into a garnet-, spinel-, and a plagioclase-lherzolite facies related to the diapiric uprise of the ultramafics from the asthenosphere into the crust. A prograde series of minerals is mapped within the marbles grading from tremolite through diopside to fosterite near the peridotite contact. These mineral assemblages form typically along an isothermal decompression path related to contact metamorphism.

ISSN:0143-1161    

DOI:10.1080/01431169608948729

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

We present a technique for automatic detection of drainage channel networks on single digital images acquired by conventional remote sensing satellites such as Landsat and SPOT. Since these satellites are Sun-synchronous, the approximate local Sun angle at time or image acquisition is always known. Consequently, the spatial behaviour of shading with respect to channels and other topo-morphological features is known. This knowledge has been used to advantage in this work.

ISSN:0143-1161    

DOI:10.1080/01431169608948730

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Information on existing landuse pattern and its spatial distribution is a pre-requisite for any watershed management programme. With the advent of remote sensing tools, with their inherent characteristics, it has been possible to prepare this dynamic resource map at various levels of confidence. But the application of multi-spectral classification techniques in vegetation discrimination has been the subject of discussion for many years.

ISSN:0143-1161    

DOI:10.1080/01431169608948731

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Models for the forecasting of crop yields using remotely-sensed satellite data are studied intensively worldwide. After reviewing the experience gained by other researchers in this field, we selected procedures which might be suitable for the estimation of corn and wheat yields in Hungary. In order to study the relations between various remotely-sensed spectral data (and their combinations) and the actually measured final yields we investigated archived agricultural and Landsat MSS spectral data for 1984. A linear relation has been sought and found between the yield data for 47 corn and 55 wheat fields in Hajdú-Bihar county and various weighted and summed spectral quantities. Among the vegetation indices derived from satellite data and corrected for atmospheric effects the most promising were the spectral indices sensitive to the green biomass. The latter, summed over a certain period in the growing season, exhibited a regression of 45-86 per cent, depending on the crop and the period of summation. Using the best models we performed regional yield estimation studies on 295 winter wheat and 218 corn fields. Taking half the crop fields used in the study we determined the yield estimation model and used this to estimate the overall crop production for the other half of the fields. The error of overall corn production estimated by this way turn out to be less than 2 per cent. The model developed for winter wheat proved to be sensitive to the wheat variety.

ISSN:0143-1161    

DOI:10.1080/01431169608948732

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

In this paper an approach to extend field information across large regions is presented and validated. Total wood volume and volume for different tree-species were estimated in a calibration area using field data, digital map information and a partial Landsat Thematic Mapper (TM) scene. Forest cover information was obtained from digital maps in the same area. The TM estimates and the forest cover information were then used to determine the statistical relations between these parameters and the spectral signature of NOAA-AVHRR pixels covering the same location. Regression analysis was used to develop this relation. The regression equations developed from the calibration area were then applied to a much larger area covering southern Sweden to estimate the forest parameters of interest.

ISSN:0143-1161    

DOI:10.1080/01431169608948733

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A method is developed to generate a top of the atmosphere clear reflectance from the Global Vegetation Index (GVI) product. Our goal is to use this dataset as a threshold to be applied to the forthcoming POLDER observations, for operational cloud detection. The method is based on the hypothesis that clouds add a high frequency signal to the slow variations of the surface reflectance in clear conditions. The validity of our algorithm is verified through an analysis of the temporal profile of the reflectance that it generates. We show that these profiles are better than those resulting from the simpler Maximum Value Composite (MVC) method. The method is applied to five years of GVI products and the results are used to derive a reference database which accounts for the interannual variability of the surface reflectance.

ISSN:0143-1161    

DOI:10.1080/01431169608948734

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Single-date classification accuracies of wheat, mustard and gram were investigated using Landsat TM data of five acquisition dates (24 January, 9, 16, 25 February and 12 March 1988) and combinations of three (TM234, TM345, TM347) and four (TM1234, TM2345, TM2347) bands over an irrigated, optimum-fertility site in Hisar (Haryana). Differences in classification accuracies were tested for significance using paired samplet-test. Inclusion of middle-infrared (MIR) bands (TM5, TM7) improved the classification accuracies in all cases except TM347 for wheat and gram. Classification accuracies with TM5 were significantly higher than comparable combinations having TM7. Lower classification accuracies with TM7 are probably due to higher within-class variability of this band.

ISSN:0143-1161    

DOI:10.1080/01431169608948735

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

It is important to estimate the area of a paddy field accurately in order to evaluate the production of rice and the methane flux from paddy fields, which contributes to the greenhouse effect. Paddy fields are irrigated and a single crop is cultivated in them. Therefore, paddy fields are easy to classify compared to upland fields and forests. However, mixels decrease the accuracy of classification and increase the error in area estimation. To overcome these problems, we developed a model to estimate the area of paddy fields in pixels from Landsat TM data. We applied this model to verification sites in Hokkaido and Miyagi Prefecture. In these verifications of our model, we were able to estimate paddy field areas with 1-4 per cent and 3-3 per cent overall error, respectively. These results show that we can apply our model to practical use.

ISSN:0143-1161    

DOI:10.1080/01431169608948736

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor