From photograph to map in RGB, NIR or multi-spectral
An orthophoto or orthophotograph is an aerial photograph geometrically corrected (“orthorectified”) such that the scale is uniform: the photo has the same lack of distortion as a map
The conversion of aerial photographs to “map” involves resampling the frames while systematically removing the distortions to create a plane surface or map.
Typical distortions in aerial photography would be:
- Lens distortion
- Terrain affects
- Camera characteristics
In creating an orthophoto thousands of individual images or frames can be assembled and mosaiced together to create a contineous, seamless image over a target area. Typically this image is still broken down into tiles to make it more “user friendly” but modern compression can also facilitate the supply of imagery of almost limitless extent and resolution.