We need a set of terms to express the characteristics of an image that we can use when interpreting the image. These characteristics are called interpretation elements and are used, for example, to define interpretation keys, which provide guidelines on how to recognize certain objects.
The following seven interpretation elements can be distinguished: tone/hue, texture, pattern, shape, size, height/elevation, and location/association.
With these seven interpretation elements, you may notice a relation with the spatial extent of the feature to which they relate. Tone or hue can be defined for a single pixel; texture is defined for a group of adjacent pixels, not for a single pixel. The other interpretation elements relate to individual objects or a combination of objects. The simultaneous and often intuitive use of all these elements is the strength of visual image interpretation. In standard digital image classification only hue is utilized, which explains the limitations of automated methods compared to visual image interpretation.