Proceedings of the Symposium on Global and Environmental Monitoring: Proceedings of the Symposium on Global and Environmental Monitoring

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Persistent identifier:: 856665355

Title:: Proceedings of the Symposium on Global and Environmental Monitoring

Sub title:: techniques and impacts ; September 17 - 21, 1990, Victoria Conference Centre, Victoria, British Columbia, Canada

Year of publication:: 1990

Place of publication:: Victoria, BC

Publisher of the original:: [Verlag nicht ermittelbar]

Identifier (digital):: 856665355

Language:: English

Document type:: Multivolume work

Volume

Persistent identifier:: 856669164

Title:: Proceedings of the Symposium on Global and Environmental Monitoring

Sub title:: techniques and impacts; September 17 - 21, 1990, Victoria Conference Centre, Victoria, British Columbia, Canada

Scope:: XIV, 912 Seiten

Year of publication:: 1990

Place of publication:: Victoria, BC

Publisher of the original:: [Verlag nicht ermittelbar]

Identifier (digital):: 856669164

Illustration:: Illustrationen, Diagramme, Karten

Signature of the source:: ZS 312(28,7,1)

Language:: English

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

Editor:: International Society for Photogrammetry and Remote Sensing, Commission of Photographic and Remote Sensing Data

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:: [THP-5 IMAGE INTERPRETATION AND ANALYSIS]

Document type:: Multivolume work

Structure type:: Chapter

Chapter

Title:: INTERPRETATION OF COLOUR-INFRARED PHOTOGRAPHS FOR THE ASSESSMENT OF FOREST DECLINE IN CENTRAL EUROPE. Claus-Peter Gross, Norbert Heidingsfeld

Document type:: Multivolume work

Structure type:: Chapter

754 2.2 Individual Interpretation Keys Since the 1960s CIR aerial photography has been succesfully applied for the assessment and monitoring of vegetation stress and disease. Systematic research in the United States, Canada, West Germany, Austria and France and a number of local tests of the me- thode have been promising /7/, /8/, /11/, /13/, /20/. However, the application of the method to in ventory forest decline in larger areas, such as ferderal states was far form being satis factory. One of the main problem is that CIR-film material reveals forest damage largely through its source "colour" and that it has not yet been possible to develop a common standard for the film material itself. Consequently the colour varies considerably according to emulsion as well as the condi tions during aerial photography /4/. Althoug the infrared balance can be influenced to some degree the criterea colour continues to be problematic to differentiate between dif ferent damage classes. This is why an indi vidual interpretation key had to be estab lished for each flight mission. The disadvan tages of these "colour" keys became particu larly clear during the 1985 inventories taken in the Federal Republic of Germany. The CIR photographs taken were marked by a striking predominance of the colour red due to the high relative sensitivity of the infrared layer in the emulsion used on these flight missions /19/. 2.3 Universal Interpretation Keys Since 1986 a group of experts at the inter pretation of CIR photographic evidence of fo rest decline from West Germany, Austria, Switzerland and Italy (Arbeitsgruppe Forstli- cher Luftbildinterpreten, AFL) has joined in a team in order to harmonize the photo inter pretation procedures and find to standards for the assessment of forest damage. One of the main goals of the team was to develop universal interpretation keys, to minimize the relevance of the colour factor as a means to differentiate between damage classes and to put more emphasis on the crown structure in the interpretation of CIR photographs. This improvement was facilitated by: - better knowledge of those damages in the morphology of the crown, which are visible in the aerial photography /14/, /15/, /17/ and - application of special stereoscopes with high quality zoom lenses which allow a highly differentiated assessment of the characteristic 3hape-types. Moreover, the use of standard terminology and identically structured interpretation keys for the entire range of applications is meant to ensure that the results of invento ries taken on different sites and different times can be compared. These are the essen tial prerequisites for the use of CIR pictu res for the comparison of national federal or reginal inventories as well as monitoring studies. These are the main characteristics of the new type of interpretations keys (Table 1), /1/: - Experts in forestry can make good use of them when studying single trees in large- scale CIR-photographs (1:3000 - 1:6000). - Five classes of "crown condition" have been defined according to damage classes estab lished in terrestrial inventories. Level 0 indicates "without visible damage", level 4 "dead". The interpretation keys for indivi dual tree species also distinguish between various types of a tree species since the appearance of "branche structure" may vary, as in case of brush-type is distinct from combe-type spruces. The appearance of such types varies in aerial photographs too, and this is why they are classified separately. - The characteristic shape of crowns and their reproduction in aerial photography are now being used as a criterion for clas sification rather than the colouring. Shape

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