Vector data is obtained through the stereo restitution of geo-referenced aerial photos. The three dimensional view in a stereo model, the observation of identical areas extracted from different photos each being viewed with a separate eye, enables the exact measurement of elevations and positions.

Analytical stereoplotters enable the observation of two aerial photos which are orientated to each other through an eyepiece. During digital photogrammetry scanned aerial photos are overlapped on a computer screen and observed through with 3D glasses. A request for different products within the context of one project will play a decisive role in the selection of project methodology.

The following gives examples of the various ways in which information can be obtained from aerial photo restitution.

Survey of Waste Disposal Sites

The amount of earth movement in rubbish dumps, slag heaps, open-cast mines and all large volume excavations is of interest from many perspectives. Regular flight surveys and restitution deliver scientifically exact results and makes a reliable prognosis possible.

Updating of Digital Maps

Nowadays an up-to-date digital map is of decisive value in meeting all requirements. The time interval between data updates therefore is continually shrinking. Ideally photogrammetry allows the direct comparison of up-to-date aerial photos with the existing data. The need for corrections or changes can be minimised and project processing speeded up.

For example this is how a geo-referenced aerial photo appears on a digital photogrammetric work station when viewed through 3D glasses. Objects can be viewed in three dimensions making it possible to measure and interpret GIS objects.
Superimposition, the overlaying of captured vector data over aerial photos, is an ideal opportunity for the updating of existing data.

This up-dated and object structured data can be supplied to the client as time stamped data (deleted, new, updated) in order to up-date client specific geographic information systems. Data can be supplied in many exchange formats.