Aerial Photography and Remote Sensing – Study Outline

Image Interpretation

You should be able to:

1. list the keys to interpretation

2. describe a feature in an image using the keys to interpretation

A. Interpretation is defined as determining and communicating the identity of features in a remotely sensed image

1. Interpretation requires a thorough knowledge of the features you are interpreting on the ground.

a. interpretation can focus on many types of features – urban, forestry, geology, agriculture, soils…

2. Regardless of the field, there are keys to interpretation that will help identify any feature.

a. size -- especially in relation to other known features in the image. Is it smaller than a house? …bigger than a football field?

b. shape

i. in general … Is it round? rectangular? irregular?

ii. in detail … Is it perfectly round? Are there irregularities in the boundary? Straight, or slightly wavy. Uniform width or variable?...

c. shadow – gives clues to height and profiles that are invisible from above.

d. tone (white to black) or color

e. texture – variations in tone across a feature that is to fine or irregular to identify the elements causing the variation

i. note strength of the variation. Is it mix of very light and dark or contrasting colors or is it subtle differences in shade?

ii. note how coarse or fine the variation

iii. note the shape of the texture elements, regular, clumpy, angular

f. pattern – how identifiable features are arranged, e.g. how houses are arranged in a subdivision., how trees are arranged in an orchard or park, mowing lines in a field

g. location and association – where the feature is relative to other known features. A square structure in the middle of a residential area will likely be interpreted differently than a similar looking structure in the middle of an industrial park.