Once you get aerial imagery from a balloon or airplane, you can 'stitch' it into a flat map in a number of ways. This helps to overlay your data on other maps, to correlate information, and can be the first step towards [creating NDVI](/tool/infrared-camera) or other image analyses. Ray Cha and Jeff Warren are currently developing a tutorial to guide first-time map stitchers. You can find the work-in-progress here: https://docs.google.com/present/edit?id=0AVY4Tg28DhosZGM0OHd6M2RfMTc0ZmpiZDk3Z2c&hl=en It may eventually become a PDF, video, and/or web page. Contact the mailing list at https://groups.google.com/group/publiclaboratory to get involved.