I do digital evalation of old aerial photos all the time. First, you need a good scanner. An Epson expression 1600 series is a good machine (up to 1600 dpi optical resolution). I generally scan paper photos in at 400 to 600 dip in B&W in a tiff format, unless I am going to really blow up the final product. Then, I can go to 1000 to 1400 dpi (I have been able to take a 1 x 1 inch area and enarge to 12x12 inches just fine). Do not do any processing during scanning. The files can be large (up to 20 meg- even for B&W). In photoshop, clean up the exposure using the level and curve command. I sometimes use just a single pass of unsharpen edge.
then, move the photo to illustrator. put the photo in a base layer and outline/map the objects of interest in another layer. Also, identify and mark 3 to 8 features that are visible on all photograhs - these will be the fiducal points- and put into a third layer. When you are done, you can throw away the photograph layer to reduce the size of the illustrator file.. When you are done with all the photos, you should have a series of small illustrator files that have the outline of the feature of interest. You can then use a rubber sheet program (such as singers's fleximap) to rectify the chosen fiducal points. Or, you can move the info into mapinfo, or autocad codes such as vector works ( one of the easiest and most power to use) s. figuers --------------------------------------------------------------------- List hosting provided by Directions Magazine | www.directionsmag.com | To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] Message number: 3772
