What is photogrammetry and remote sensing?

Photogrammetry and remote sensing are sciences concerned with the acquisition of information from images. In photogrammetry the emphasis is layed on geometric information, while in remote sensing thematic information is more important. 

In remote sensing a wide range of sensing devices is applied, usually mounted in a satellite or in an aircraft. The sensors can be sensitive to a large range of wavelengths of the electromagnetic spectrum. Airborne Laseraltimetry is a recent development in remote sensing with great potential for creating high resolution and accurate Digital Elevation Models. 

In photogrammetry only the (near-)visible part of the electromagnetic spectrum is used. The storage of images in digital form makes computer processing possible and thereby the (partial) automation of the photogrammetric process. Photogrammetry can be split-up in two fields, namely aerial photogrammetry and close-range photogrammetry (sometimes called terrestrial photogrammetry). In aerial photogrammetry photographs are used that are taken by a special camera mounted in an aircraft. Aerial photogrammetry is used for topographic map production and like remote sensing as a data acquisition technique for Geographical Information Systems (GIS). 

In Close-range photogrammetry all sorts of camera's are used including the standard 35-mm camera. It can be looked-upon as a non-contact three dimensional measurement technique. Close-range photogrammetry is applied for a diversity of measurement tasks in fields such a medicine, industry and architecture. The resulting 3D-models are often input to a CAD-system for further processing or visualisation.