Visual Interpretation

For exercise 1, I had to learn how to identify features using tone and texture. I began with “tone” which is how light or dark something is, and created a feature class for each classification. This is done by highlighting the .gdb file in the ArcCatalog pane, right-clicking, and selecting new feature class with polygon geometry. I added the Tone feature class to the map by dragging it over. Then, I added each feature name opening the attribute table for Tone, and adding a field for each feature. Lastly, I would create the polygon for each feature by highlighting the feature in the attribute table, selecting edit>create feature>polygon. I repeated this process for Texture For labeling purposes, I chose the polygon lines to be a bright blue color (Tone) and a bright red color (Texture) with a 2pt width because I needed it to stand out on an otherwise colorless background. The 5 classifications I used for Tone were Very Light, Light, Medium, Dark, and Very Dark. The 5 classifications I used for Texture were Very Fine, Fine, Mottled, Coarse, and Very Coarse. Some examples of features I chose for tone and texture were an airport for very light, calm water for very fine, and a neighborhood for coarse. Some features had varying tones/textures such as vegetation.

 For exercise 2, I had to visually identify features using the criteria of shape/size, shadow, pattern, and association. I used the same steps as in exercise 1 to create feature classes for each criteria except this time I used point geometry. Shape/size is the most intuitive and easiest identifying feature to begin with. Without having to zoom in or study the aerial photo long, I was able to identify a pier. I was pretty sure I located a two swimming pools but after zooming in slightly, I was 100% sure. I did have to zoom in very close and pan around the photo to see other features more clearly. This allowed me to easily identify a vehicle. I remained zoomed in when I chose the three features for shadow. I chose trees, a motel sign, and a water tower because they had clear shadows being cast. I almost chose buildings because so many had shadows but decided to use the examples that would be very difficult to identify without that one criteria (buildings have multiple criteria). Pattern is almost as intuitive as shape/size for identifying features, in my opinion. It was easy to locate the waves in the body of water, the multiple transmission lines, and the lined spaces for the parking lot. For association, I chose the motel and the neighborhood clubhouse. Each building contained a swimming pool which helped signal the association. For labeling purposes, I employed a few techniques for the map to stand out, as I was dealing with another colorless background. I used 5pt circles with different colors for each criteria. For the labels, I used the Point of Interest text symbol with “white halo”. However, I changed the color of the halo to match the symbol color, used with the underlying black text. I felt this aesthetic was pleasing to the eye. 

For Exercise 3, I explored color interpretation by comparing a true color image and a color infrared image. The mixed pine forest area southwest of the area initially appeared green to me but it was entirely red in the false color image thus its true color was near infrared. The marsh was easy to discern as its true color was green and false color was blue. There were some areas that I interpreted as rivers/water retention areas that were white in true color and blue in false color. I concluded that these could be possible construction or industrial areas that do not contain runoff all of the time. The buildings appeared to be white in both true color and false color because they reflect light. We did not have to make a map of this exercise but it was good practice to see how having a thorough understanding of your area and how true/false color can help you understand features in an aerial photograph.