Digital Photogrammetry, which is also, addressed as soft copy Photogrammetry emearged gradually between 1982 to 1990. Developments in soft copy Photogrammetry have accelerated and innovations towards softcopy systems is driven not by Photogrammetry, but by computer technology. The softcopy Photogrammetry is a symbol for new philosophy in Photogrammetry, which has changed the way of processing, performing and distributing the photogrammetric products.
The fundamental features are the fully digital environment using digital images and the production of digital output in an interactive and automated fashion. With the universal tool of a softcopy Photogrammetric workstation, even a non-photogrammetrist can generate 3D data from those image products in an accurate, reliable way with 3D data consisting not only of pure co-ordinates, but of meaningful semantic descriptions of objects.
A softcopy Photogrammetry system can handle many different data sources in mapping and industrial applications. It is a tool for integrating disciplines and applications using the same hardware platform. The application areas can be broadened by users. A digital photogrammetric workstation is not necessarily a part of GIS or remote sensing system; it can be vice-versa as well.
Advantages of softcopy system :
Most of the mapping organizations choose to invest in the softcopy systems because of its efficiency and price/performance of the softcopy systems in producing digital orthos. Digital ortho production was the most common application and the huge reduction in price offered by softcopy versions the analogue ortho systems was a major factor.
Another major reason was the potential of images matching using correlation to assist the operator in DEM data capture.
The other advantages of digital photogrammetric workstations are
No high precision optical/mechanical components required.
No regular instrument calibration required.
Digital images are stable.
Images can be loaded with out manual operation.
The stereo model can changed ‘on the fly’
An optimum image presentation can be chosen for human interpretation.
Online stereoscopic measurements are possible.