I have (god help me) been tasked with the task of doing an areal survey of Stratford upon avon.<br><br>The background can be seen here.<br><br>Basically (at the last draft) it involves taking photos out the side window of a Cessna with a 12mp DSLR while flying 5 concentric circuits round the town. <br>
<br>Due to weather, it could be as soon as Thursday that I fly, so i need help fairly quickly.<br><br>Now I'm an experienced photographer, but I'm never taken photos from a plane before, i need advice form people that have done this before.<br>
<br>Questions:<br><br>Ortho rectification -- how exactly is it done, and is there anything that i need to look out for when taking the photos -- it is really critical to me that i know what's going on before the flight.<br>
<br>Specifically how much overlap do the images need? from my panoramic experience, i always take at least 50% overlap, so if any image fails, i have others that can fill in the gaps, it also helps with automatic alignment tools. are such tools available for aerial work, or is it just a monkey dragging image corners onto a map?<br>
<br>How critical are lens characteristics? I have 2 nice prime lenses one of which has a known close to flat field. I also have a zoom lens that would be perfect, (Zeiss 16-80) it's sharp but it's field is not perfectly flat, and being a zoom, it's length is not perfectly repeatable (although i do plan on using it at it's extreme long end mostly) It would allow me to get wider shots when needed.<br>
<br>I plan on taking photos looking outward towards the horizon from the outer edge of the survey area, is this useful/advisable/problematic? Is there any problem when rectifying of images that are wide enough to go above the horizon, I imagine this would break some of the maths.<br>
<br>Any other tips?<br><br>Thanks,<br>JR<br>