Thanks to everyone for their advice. What rapid responses from a great group of people.
Most people suggest ER Mapper will do the job of orthorectifying the images, other suggestions have been ERDAS, Intergraph ZI or Aerial 5 developed by Bradford University. However, most people also suggest that it would be much better to purchase properly ortho-rectified images as they won't be too expensive compared to the time and effort (and money) spent using the various software programs to do the job. I have passed all the information on to the client, and will see which they go for. Thanks for all your help Regards Caroline -----Original Message----- From: Photogrammetry GIU [mailto:[EMAIL PROTECTED] Sent: 06 September 2004 10:19 To: [EMAIL PROTECTED] Subject: Re: MI-L Rectifying stereo aerial photos Hi Caroline You are going to hit a big problem very rapidly of ground height and the high probability of the original photographs not being genuinely vertical. The best solution for you is to get the client to purchase orthorectified images (Distortions due to ground height, camera attitudes and lens removed and not cheap) that will be at a constant scale, such as UK perspectives, et al, imagery. This imagery can then be fed backwards through the relevant height dtm of the area to produce stereo imagery that is georeferenced. However any vector data that you wish to superimpose will also have to be converted to a raster format and height distorted so that it will lie on the stereo image, rather than float in a misregistered manner along side the stereo pair. I attach a cheap and cheerful stereo image of an area in Dorset, (subsampled to 5m or so) that illustrates a stereo pair. Note that the image is copyrighted to EN and UKp Software used in this case is Intergraph's ZI package. Good luck Tony >>> [EMAIL PROTECTED] 06/09/2004 09:40:47 >>> 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 The average family throws out six trees of paper a year - please respect the environment and be green by example, only print out this E-Mail and attachments if you have to. Thank you. This E-mail and any files transmitted with it are private and intended solely for the use of the individual or entity to whom they are addressed. If you are not the intended recipient, the E-mail and any files have been transmitted to you in error and any copying, distribution or other use of the information contained in them is strictly prohibited. Nothing in this E-mail message amounts to a contractual or other legal commitment on the part of English Nature unless confirmed by a signed communication. English Nature will make every effort to keep its network free of viruses. However, the recipient of this message will need to scan this message, and any attachments, for viruses, as English Nature can take no responsibility for any computer virus that might be transferred by this e-mail. --------------------------------------------------------------------- List hosting provided by Directions Magazine | www.directionsmag.com | To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] Message number: 13233
