Remote sensing for resources development and environmental management: Remote sensing for resources development and environmental management

Damen, M. C. J.

Bibliographic data

Multivolume work

Persistent identifier:: 856342815

Title:: Remote sensing for resources development and environmental management

Sub title:: proceedings of the 7th international Symposium, Enschede, 25 - 29 August 1986

Year of publication:: 1986

Place of publication:: Rotterdam; Boston

Publisher of the original:: A. A. Balkema

Identifier (digital):: 856342815

Language:: English

Additional Notes:: Volume 1-3 erschienen von 1986-1988

Editor:: Damen, M. C. J.

Document type:: Multivolume work

Volume

Persistent identifier:: 856343064

Title:: Remote sensing for resources development and environmental management

Sub title:: proceedings of the 7th international Symposium, Enschede, 25 - 29 August 1986

Scope:: XV, 547 Seiten

Year of publication:: 1986

Place of publication:: Rotterdam; Boston

Publisher of the original:: A. A. Balkema

Identifier (digital):: 856343064

Illustration:: Illustrationen, Diagramme

Signature of the source:: ZS 312(26,7,1)

Language:: English

Usage licence:: Attribution 4.0 International (CC BY 4.0)

Editor:: Damen, M. C. J.

Publisher of the digital copy:: Technische Informationsbibliothek Hannover

Place of publication of the digital copy:: Hannover

Year of publication of the original:: 2016

Document type:: Volume

Collection:: Earth sciences

Chapter

Title:: 3 Spectral signatures of objects. Chairman: G. Guyot, Liaison: N. J. J. Bunnik

Document type:: Multivolume work

Structure type:: Chapter

Chapter

Title:: The use of Thematic Mapper imagery for geomorphological mapping in arid and semi-arid environments. A. R. Jones

Document type:: Multivolume work

Structure type:: Chapter

. 'I'able 2. Effectiveness of single band imagery in extracting semi arid geomcrphology. SCORE USED IN ASSESSING EFFECTIVE EXTRACTION OF SUBJECT:- Good 12, Moderate 8, Poor 4, Not Visible 0. IMAGE PROCESSING TASKS Single bands and FCC (linear stretch) GEOMOFPHIC PHENOMENA Geological structure Lithol. discrimination Solid-drift boundary Fan entrenchment Anastomosing fans Occurence of croutes Dep. from playa Fan-playa boundary Variation within the playa Alluvium River channels Eio-geomorphic 1 2 3 4 5 7 123 345 457 8 8 12 12 12 12 12 12 12 0 4 8 12 12 12 4 12 12 0 12 12 12 8 8 4 12 12 4 4 8 8 12 12 4 12 12 4 8 8 4 12 12 8 8 8 8 8 8 4 4 8 8 4 12 4 4 8 4 8 12 12 8 8 4 8 8 12 8 12 8 8 12 4 8 8 12 12 12 4 12 12 4 12 12 8 4 4 8 8 8 8 8 8 8 12 12 8 12 8 12 12 2 4 8 8 8 12 12 It is apparent from the table that some TM bands contain more information for specific geomorpholog- ical phenomenathan others, especially by bands 2 anu 3 picking up alluvium while the infra-red bands are better for lithological discrimination. The striking point to note is that some bands score very similar for the same feature, a fact mirrored by the FCCs. This suggests that the amount of geomorphological information held in TM bands is very similar for certain features and little extra information is contained in FFC for the same phenomena. Visual ex amination of the images suggests that the bands show a marked degreeintercorrelation and this is shown in Table 3. Strong correlations^ are displayed between all bands with even stronger relationships among the visible bands, the middle infra-red bands and band 4 and the other bands. It is well known that the TM was designed primarily for vegetation discrimination with bands selected to take advantage of the spectral response of vegetation (Salomonson er al. 1980). The implication from this study is that for investigations of bare, arid (ie non-vegetated) surfaces, after studying an infra-red or an FCC, additional single TM bands are of little value unless very specific ranges of pixel values are utilised. Table 3. Correlation matrix derived for six reflect ive TM bands for the El Guettar test area. and as a result it is not possible to show an example in this paper. A basic but powerful image processing technique is the ratioing of two spectral bands. This reduces topographic noise and enhances subtle spectral differences of surface features. However, to effectively use such methods, the relationships bet ween the surface material and its spectral response must be understood. Hunt & Salisbury (1976) and Kahle (1982) have shown that up to a wavelength of 2.5um, there is an increase in absorption of reflect ed energy by clay particles. Thus a ratio of TM band 5 (1.55-1.75um) and band 7 (2.08-2.35um) will display the occurrence of clay particles as lighter tones. In the 5/7 ratio (Fig. 7a), the light area in the cen tre of the chott corresponds with the unvegetated part of the playa where clay particles are expected. It is interesting to note that the high concentration of clays on the southern alluvial fans and on the south western part of the image which is subjected to aeol- ian deposition from the playa. 1 2 3 4 1 1.000 2 .963 1 .OOO 3 .948 .983 1.000 4 .891 .937 .953 1.000 5 .807 .880 .911 .918 7 .812 .885 .910 .905 1.000 .974 1.000 An effective processing technique for single band imagery is edge enhancement or convolved images. This allows the user to highlight a boundary or edge in the image by smoothing out other detail. Edge enhancement operates by passing a digital filter or kernal, in the form of a matrix, over the data and has been very successful in many studies of geologic al lineaments (Bailey et al. 1978). Figure 6 shows the result of passing two different filters, a north (Fig. 6a) and an east (Fig. 6b), over the image. Note how the north filter picks out the mountain-fan- playa boundaries which is not as evident in the other filtered image. The simplest multiband processing technique is the production of false-colour composites using single band imagery and as stated previously, they contain very little additional information. This can be im proved by an Intensity, Hue, Saturation transform which is simply a rotation in colour space. The eff ectiveness of this processing is best shown in colour

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