I am very new in GIS and I am trying to ortho-rectificate my images. But after putting it on the map I see that results are not precise. We have images taken from the airplane, it's longitude, latitude, elevation, omega, phi, kappa.
What is the best way to calculate rectification for our images? Is there any third party libraries for that? Or at least some tool to compare it with my results?
Thanks in advance!
Serhiy.
UPDATE: what I am trying to do is to find how images are projected to the ground by using latitude, lontitude, elevation and angles (omega, phi kappa). Calculate 4 corners of that image and then georeference each image. After that I think I can make precise mosaic.
UPDATE 2: I spent almost whole day on GRASS but without any luck, it is not so simple and not intuitive.
I read that Direct Georeferencing is what I need. I found a lot of mathematical articles on internet and tried to write my own implementation, but it is not very precise. Is there any simple tool or library that can take coordinatates (x,y,z), angles(omega, phi, kappa), elevation, image height/lenght (in nadir position) or focal lense and calculate 4 coordinates that correspond to corners of the image on the ground?
Best Answer
If you want to do a "true" ortho-rectification, you need a DEM. the DEM could come from an ancillary source or from photogrammetry using a second photo that overlaps yours. If you don't have a precise DEM, geometric corrections with Ground Control Points becomes an alternative to the orthorectiication (the information about the plane position and viewing angles is then useless).