Photogrammetrie

Geodesy and Geoinformation: What's that?

 

Photogrammetry

Already a few years after the invention of photography, i.e. approx. 150 years ago, the possibilities and opportunities were discovered and developed to deduce the geometry of objects from the perspective fixed in the photo. Measurements in photos replaced measurements at the object, which could be of any size. Photogrammetry was born and has since then developed to a current and very efficient method in surveying and geodesy.

Photogrammetry uses a variety of imaging sensors. For airborne photogrammetry still today conventional film based cameras are in use. At the same time the digital camera technology is increasingly used. Moreover in the last years systems are applied based on laser light or micro wave to derive digital terrain models by sensing the Earth's surface.

For the processing of the data registered with these systems the procedures are developed and teached with a special emphasis on digital data and object models. Especially the treatment of data and object models is nowadays in the focus for further development of automatic procedures. The airborne and spaceborne sensor systems open the way to derive topographic and environment related 2D and 3D data, which can be used in conventional way for topographic and thematic maps, but nowadyas increasingly for information systems and data bases. Beside geometric information also spectral information is extracted and exploited from the recorded data in order to classify objects and compile inventories.

In this field the photogrammetry is fading into the field of remote sensing which is shortly introduced here as well. Another increasing focus in photogrammetry is the automatic recognition and modeling of object pattern in digital images, e.g. for the creation of city models for Geo Information systems, visualisations, network planning etc., in order to supply Geo data in the future in a fast and efficient way and at reasonable cost.

The digital image processing in photogrammetry and remote sensing and its fast growing potential open up new fields of activity for geodesists and surveying engineers in the areas of architecture and engineering, e.g. for documentation, reconstruction and visualisation of monuments, for validation of production output and much more.