Hello Maning, Yes the actually important data concerns the camera properties. I fear your images won't be easy to handle : I guess your camera is not properly an aerial survey camera system, is it ? each image should show fiducial marks on its edges, and you should have a calibration certificate providing data such as focal length, fiducial marks position and so on. Let us know a bit more about the camera.
Le samedi 05 janvier 2008 à 15:24 +0800, maning sambale a écrit : > Hi, > > I have a lot of aerial photos I need rectify. The data came from an > incomplete project intending to acquire geospatial data for landslide > risk assessment. > The project ended prematurely. > > Here are the details: > Images were acquired using this method. > > Two GPS receivers were used, one attached to the laptop to facilitate > the navigation of the > airplane and the other to the camera to determine the geographic location of > the > center of the photographs. The plane flew along the flight lines > indicated in the plan. > The photographs were taken along the flight line using a professional > Kodak N14 digital > SLR camera, which has a resolution of 14 megapixels. The camera was > fastened to a > mount, made from plywood and customized to accommodate the camera and the > laptop > computer. The seat next to the pilot was detached to make room for the mount. > A > camera door, designed specially for this purpose, replaced the normal Cessna > 172 > passenger door. > > What do I have now: > over 800 photos > GPS point location for each photo > Quickbird image of the whole study area > > According to their report: > There is difficulty in mosaicking the photographs. The > original plan was to stitch the photographs together to create a > composite image. > But the tilt in the photographs due to the movement of the aircraft > requires that > certain adjustments be made. > > Any ideas on how to resolve this. As far as I know, you need certain > camera parameters to orthorectify aerial photos > CAMERA NAME: camera name______ > CAMERA IDENTIFICATION: identification___ > CALIBRATED FOCAL LENGTH mm.:_________________ > POINT OF SYMMETRY (X) mm.:_________________ > POINT OF SYMMETRY (Y) mm.:_________________ > MAXIMUM NUMBER OF FIDUCIALS:_________________ > > > How do I get this? Is it OK to rectify the imges from the quickbird > satellite data? > > cheers, > > maning > _______________________________________________ > grass-user mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/grass-user > _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
