Followings are the key elements which assist in visual image interpretation (Lillesand and Kiefer, 2000):
Shape refers to the general form, configuration, or outline of individual objects. Size of objects on images must
be considered in the context of the image scale. Pattern refers to the spatial pattern arrangement of objects.
Tone refers to the relative brightness or colour of objects on an image. Texture is the frequency of tonal change
of an image. Texture contains important information about the structural arrangements of surfaces and their
relationship to the surrounding environment (Kushwaha et al., 1994). Site refers to topographic or geographic
location and is particularly important aid in the identification of vegetation types. Association refers to the
occurrence of certain features in relation to others (Lillesand and Kiefer, 2000).
Further, the image interpretation process can often be facilitated through the use of image interpretation
keys (Lillesand and Kiefer, 2000).