PhotogrammetryThe 3D imaging of the surface and everything on it has been done for decades from airplanes and satellites. Photogrammetry is the creation of maps from digital aerial photographs which have been made with special high-resolution cameras. More specifically, this is called aerial photogrammetry. Using lightweight cameras, these high resolution 3D aerial photographs can also be made by drones. With special software the photos can be processed and manipulated. This technology can be used for many different purposes. Besides maps and geo-information photogrammetry can be used to generate digital aerial photographs, digital orthophotographs, 3D relief models, high density point clouds and ortho mosaics. These 3D spatial data of (objects on) the earth's surface can be used to calculate distances, surfaces and volumes. The current technology allows us to make elevation models with a resolution and vertical precision of better than a few centimeters.
How does it work?To create the digital photographs, high resolution digital photocamera's are used making vertical (for stereo photographs at least with an overlap of 30%) or oblique (with an angle of 45° for depth effect) photographs of the earth's surface.
Below left: 3D representation of an open pit mine.
Below right: Graphic of stockpile volume of the open pit mine. Traditional survey techniques (vertical axis)are compared to Smartplanes photogrammetry (horizontal axis). The graphic shows a 1:1 correlation between the two methods.
Left: Comparison of the results for an area where an airborne LiDAR survey and a drone-photogrammetry survey have taken place at the same time. The graphic shows the difference (in cm) between the two methods.