Visual Interpretation

Tone and Texture

Identifying features in aerial photographs is not always a simple task. Fortunately, there are several principles and techniques available to analysts that can assist in interpreting aerial photos and help make sense of the images captured. First of all, it is important to be familiar with the various tones and textures one may encounter when interpreting aerial images. The map below highlights areas with five different tones (very light, light, medium, dark, and very dark) and five different textures (very fine, fine, mottled, coarse, and very coarse). Considering the tone and texture of an area or object can be a good starting point when interpreting aerial photographs. 

Identifying Features

There are also several identifying criteria that can be helpful when interpreting aerial images -- shape and size, shadow, pattern, and association. Shape and size define what an object "looks like", shadows provide an extra angle of vision of objects that cannot be seen at or near nadir, patterns in arrangements can help identify features that would not be distinguishable as individuals, and association involves looking for identifying clues provided by the context of a feature. The map below shows the primary criteria used to identify several features within an aerial image.