648 -
Geländereliefs betont die Möglichkeiten, welche durch Profilschraffen
einer Orthophotoproduktion eröffnet werden. Durch die Untersuchung eines
Dolinen gebeites mit Hilfe eines Quantimet wird eine quantitative Analyse
auf Grund von Densitätseigenschaften demonstriert. Schliesslich wird eine
quantitative Analyse mittels RichtungsStrukturen durch eine Untersuchung
von einigen Gelände formen beschrieben, wobei von Methoden des optischen
Filterung mittels kohärentem Licht (Laser) Gebrauch gemacht wird.
INTRODUCTION
The rather spectacular development of image recording techniques in recent
years has overshadowed to some extent the equally important developments in the
field of image analysis. The diversity and quantity of images now being produced,
on the other hand, invite a study into more sophisticated interpretation techniques.
Image interpretation for the study of terrain rests on the study of relief and/or of
density characteristics. Relief characteristics and photographic densities or tonal
signatures can be applied to the identification of terrain features and also serve
for mapping the spatial distribution of the latter.
Relief characteristics are generally more important as indicators in geomorphol-
ogical studies than density characteristics since they are directly related to land-
form. Optimum conditions for relief analysis (section 2) are offered by stereos
copic vertical aerial photographs. Orthophotographs have special merits. Stereos
copic study of other types of images, such as oblique photographs and SLAR
images, though less satisfactory, is also of importance. In the case of photo
graphs taken from orbiting satellites or other space vehicles only the major ter
restrial relief can be seen three-dimensionally but stereoscopy, if obtainable, is
nevertheless a considerable help.
If no stereoscopy can be obtained, the relief characteristics are only revealed
through shadow patterns, drainage networks, textures, etc. , and thus have to be
studied through density characteristics. The density patterns of hilly and moun
tainous terrain resulting from the reflectance/emittance characteristics of the
objects (MINNUS, 1967; STEINER-GUTERMANN, 1966) and the sensitivity
characteristics of the recording system, are strongly affected by the exposure
of the slopes, by shadows, etc. Density analysis of areas of relief is thus of
limited value only.
Grey tones or photographic densities only rank second in importance in image
analysis for the study of terrain as compared to the interpretation of the
