Module 1: Visual Interpretation

The objective of this lab was to learn some of the basic principles of interpreting features found on aerial photographs.

In the first exercise, I learned how to identify tone and texture on an aerial photograph. The tone is the brightness or darkness of an area whereas the texture is the smoothness or roughness of a surface. I accomplished the objective by creating 5 polygons for tone and 5 polygons for texture. To interpret tone values for the aerial, I identified and created polygons showing 5 different areas of tone as follows: very light, light, medium, dark and very dark. To interpret texture values, I identified and created polygons showing 5 areas of texture as follows: very fine, fine, mottled, coarse and very coarse.
           Fig 1. Map showing a range of values of tone and texture on an aerial photograph.
In the second exercise, I learned how to identify features on an aerial photography based on the following 4 criteria: shape and size, shadow, pattern and association. I accomplished the objective by creating 3 points identifying features based on shape and size, 3 points identifying features based on their shadows, 3 points identifying features based on a pattern, and 2 points identifying features based on associations with nearby features.  
           Fig 2. Map identifying features on an aerial photograph based on shape and size, shadow, pattern and association.

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