摘要:

In September 1982, NERC funded an airborne campaign using a Daedulus airborne thematic mapper multispectral scanner. A total of 18 sites were flown for 10 experimental groups in the U.K. The major aim of the survey was to provide spectrally simulated satellite data for small test sites, particularly in support of ongoing LANDSAT-4 investigations. However, the survey demonstrated that in certain situations when timely satellite data cannot reasonably be expected, e.g. tidal sites, aircraft provide an important data set. This brief paper provides a summary of the NERC airborne campaign and an introduction to the related papers to be found in this issue.

ISSN:0143-1161    

DOI:10.1080/01431168408948847

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Remotely sensed data were collected using an airborne Daedalus thematic mapper, flown at 4000 m, over Swansea Bay, northern Bristol Channel, U.K. The area is one of high tidal range and wave activity. Fifty-eight surface-water/sediment samples were collected from three vessels as concurrent ‘sea-truth’ data. Samples were analysed for suspended sediment concentration (SSC)

ISSN:0143-1161    

DOI:10.1080/01431168408948848

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The Lower Swansea Valley contained some 162 hectares of waste tips at the start of reclamation. This paper describes a project using MSS-82 airborne thermatic mapper simulation data to evaluate the role of remote sensing in assessing, classifying and mapping contaminated and other surfaces. Bare surface materials are discriminated and various classes of metaliferous waste identified, notably residue from copper, zinc and iron smelting. A vegetated surface under which there was contaminated material was also identified with the aid of principal component analysis.

ISSN:0143-1161    

DOI:10.1080/01431168408948849

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Airborne multispectral scanning system (MSS) data from the Natural Environment Research Council's MSS-82 project were used to estimate the green-leaf-area index (GLAI) of an area of semi-natural and agricultural limestone grassland. This research is the pilot study of a five phase investigation which will ultimately test the feasibility of using airborne and spaceborne MSS data to estimate GLAI over large areas. The pilot study was designed around four stages: (i) derivation of the relationship between multispectral reflectance and vegetation amount using ground radiometric data collected in the field, (ii) production of a perpendicular-vegetation index (PVI) image, (iii) production of a GLAI image using the relationship between PVI and GLAI and (iv) accuracy assessment of the resultant GLAI image. Due to a number of project- and environment-specific problems the proposed methodology was modified and GLAI was predicted to an accuracy of 50-86 per cent at the 95 per cent confidence level. For the future, a change of project design and the use of a vegetation model to correct for environmental anomalies will enable the technique to be used to greater effect.

ISSN:0143-1161    

DOI:10.1080/01431168408948850

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Multispectral scanner system data simulating the thematic mapper (TM) of LANDSAT-4 were analysed for an area near Gedney Hill, Lincolnshire, U.K. The data were found to have a three-dimensional statistical structure similar to that for the LANDSAT-4 TM of parts of the United States. Divergence analysis indicates that the optimal choice of bands for cover discrimination should include one band from the visible, one from the near-IR (infrared) and one from the middle- or far-IR. It was further shown, primarily from consideration of principal-component images, that significant discriminatory power may be lost if all bands are not used. Comparisons with LANDSAT-4 TM principal-component images are made. The role of noise factors in obscuring information, especially from highly correlated bands, is shown to be of considerable importance.

ISSN:0143-1161    

DOI:10.1080/01431168408948851

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Three approaches have been adopted to assess the importance of individual spectral bands in data from an airborne multispectral scanner flown over part of the English Fenlands; these involve (i) an analysis of the interrelationships between the spectral bands, (ii) a study of the spectral response of materials and (iii) a study of the relationships between physical properties of materials and their spectral responses. Results indicate that where exposed surface materials are found, all spectral bands are strongly positively correlated (r>0.866) with one another, apart from the thermal band 11 which is negatively correlated (r < -0.73) with all other bands. Study of the spectral response of materials suggests that the two middle-infrared bands, 9 and 10, reveal the greatest spectral range and variability, providing maximum contrast in relation to changes in surface material. Additionally, the thermal band 11 is found to be the best discriminator between the sandy central-channel material and surrounding clay materials.

ISSN:0143-1161    

DOI:10.1080/01431168408948852

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The effect of view angle upon the detected spectral response of vegetation canopies is studied, using NERC 1982 airborne multispectral scanner campaign data. An attempt is made to distinguish between the effects of atmosphere and the anisotropic reflectance of vegetation canopies. The influence of atmospheric backscatter is found to be greatest at very short wavelengths (0.42-0.45 μm)

ISSN:0143-1161    

DOI:10.1080/01431168408948853

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Multispectral scanning was evaluated as an aid to the rapid assessment of sand and gravel resources in areas of scattered drift deposits. In the area chosen, where glacial sands and gravels, tills, river terrace deposits and alluvium overlie Mercia Mudstone Group mudstones with thin sandstone bands, it was found possible to delineate areas of alluvium and outcrops of sandstone, but not to distinguish sands and gravels from till clays or from mudstones. The reasons for these results are discussed.

ISSN:0143-1161    

DOI:10.1080/01431168408948854

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Multispectral imagery was obtained at six altitudes from 500 to 3000 m over a single site on a hazy day. At each altitude, digital values— proportional to radiance—were averaged over selected areas on the ground. The effect of scattering was eliminated by taking differences between areas and the attenuation coefficient determined from the change with altitude. Values ranged from 0.1 km−1in the near-infrared to 0.3km−1in the blue wavebands. The scattering was determined by applying these coefficients to the original data. In all bands the scattering profile varied considerably with height with a peak in the 1000-1500m layer. This peak corresponded to a layer of high humidity found in the radiosonde data and suggests the presence of hygroscopic aerosol. The airborne data were extrapolated to the ground and were calibrated by reference to a reflectance measurement at the surface. It is proposed that such multiheight techniques could be used as a means of correcting for atmospheric effects in applications of remote sensing where radiometric fidelity is important,

ISSN:0143-1161    

DOI:10.1080/01431168408948855

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor