Module 2 - Visual Interpretation

Welcome to the first blog post for my GIS4035 Remote Sensing class! The class started with readings and lectures to familiarize us with remote sensing and the history of aerial photography before moving on to lab assignments. The history was very interesting-I had no idea how important aerial photography in military reconnaissance as far back as WWI!

This lab was about visual interpretation of aerial photographs. The first exercise focused on tone and texture. Using the Draw tool I created polygons around areas that represented different tone and texture values, such as very light, medium, very coarse, mottled, etc., then saved the graphics as features in a shapefile. The second exercise consisted of identifying features based on four criteria: shape and size, shadow, pattern, and association. Some features, such as buildings or cars are easily identified, but some require looking at shadows to understand the object's planar form, like trees and streetlights. Or sometimes using association, like a long skinny object being identified as a pier because it connects beach to water. The final exercise was a comparison of how objects look in a true color photo versus a color infrared photo. Interesting to see some expected results, like green trees appearing red, and some unexpected results, like brown dirt (or so I think it was) being light blue.

All in all a nice start to one of my final classes in the certificate program.

Identification of areas that represent various levels of tone and texture. 

Identification of features using 4 criteria to assist in visual interpretation including shape and size, shadow, association, and pattern.