The visual smoothness or coarseness of the image creates its texture. Shadows Shadows can both help and hinder the interpretation process. A shadow allows you to see the profile of an object, potentially making the object more easy to identify. However, objects within shadows may be difficult to identify because they reflect little light. Site Consider what types of trees would grow in the geographic location of the photo, or what types of trees would grow in the soil type.
Association Consider placement of cultural features.
If so, then perhaps the object that you cannot identify is a Ferris wheel. To help with airphoto interpretation, you might be able to obtain an interpretation key. Keys might have pictures with text labels so that you can identify an object by comparing it to the pictures. Selective keys are also available that allow you to identify an object using the process of elimination. One example of such a key is a dichotomous key that gives you 2 choices at each level, continually narrowing down your options.