Usefulness/Pitfalls of Image Rectification: Once an image has been rectified with a reference, locating points of interest become much easier. In the Pensacola image (above at left) it could be difficult to identify specific buildings, a school for instance. But, after rectifying, the coordinates of a particular school could be taken from the reference map (above at right) and the school could then be pinpointed on the image. A particular issue I had with rectification arose after I placed the first check point. The next one would vanish. I assumed my control points were bad, so I started over with a new set. I ran into the same issue: vanishing check points. I tried them in several places and noticed a distinct pause before rejecting the potential check point. I tried several more until the next one found a permenant home. It required quite a bit of trial and error with check point placement until I had the requisite five sited. My final check point error was 2.27.
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