As the term states, Logical inference means that the interpreter applies reasoning. In the reasoning, the interpreter uses acquired professional knowledge and experience. Logical inference is, for example, concluding that a rectangular shape is a swimming pool because of its location in a backyard garden near to a house. Sometimes logical inference alone is insufficient to interpret images; then field observations are required.
Consider the areal photograph in the Figure below. Are you able to interpret the material and function of the white mushroom-like objects in the photograph below? A field visit would be required for most of us to relate the different features to elements of a house or settlement.