Hi Caroline, As far as I know, you can't use such images for immidiate backdrops in MapInfo, since they're "flattened" yielding severe height distortions.
I was involved in a similar project a long time ago, and the images then were only rectified for tablet digitizing with up to 9 points 3D ground control points arranged in a 3-by-3 pattern across the image (visualize 8 slices in a square pizza) . The resulting (3D) corrections was fairly reasonable, but it was only used for digitizing more-or-less fuzzy habitat areas, so the need for accuracy wasn't too overwhelming. Mosaicing seems to be a better choice, if backdrops are what you want. Best regards/Med venlig hilsen Lars V. Nielsen GisPro, Denmark http://www.gispro.dk/ ----- Original Message ----- From: "Caroline Hilton" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Cc: "Joe Piggott" <[EMAIL PROTECTED]> Sent: Monday, September 06, 2004 10:40 AM Subject: MI-L Rectifying stereo aerial photos > Hi Listers > > A client of mine has purchased some hard-copy aerial stereo-photos and > wants to scan them for use as a base layer in MapInfo. > > These photos are not rectified in any way for digital use, as they are > designed for viewing in stereoscopic pairs. > > Obviously, the client is concerned about the distortion at the edges of > the images - he is planning to use 5 photos for the area concerned. Once > registered there is about 150m distortion at each photo edge. Placing > vector layers onto the images is obviously going to be a problem as > registration will be different for each photo image, so they will not > currently display properly in MapInfo. > > Is there any software which will rectify the photos? (is this > "ortho-rectifying"?). Or would specific rectified digital images need to > be purchased for mosaicing in MapInfo? > > I have only used digital images, and have not tried using stereographic > images for this purpose, so cannot advise. > > Any advice you may have for using these images in MapInfo would be most > welcome. I will forward it to my client. > > Thanks > Caroline > ---------------------------------- > Dr Caroline Hilton > Pelican GeoGraphics Ltd > UK > [EMAIL PROTECTED] > www.pelicangeographics.co.uk > > --------------------------------------------------------------------- List hosting provided by Directions Magazine | www.directionsmag.com | To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] Message number: 13228
