The first concept of ORIENT has been presented at the Helsinki Congress of the International Society for Photogrammetry and Remote Sensing (H. Kager, K. Kraus, 1976). The final implementation is based on a unified approach where all transformation formulas used originate from the spatial similarity transformation. ORIENT was operational already in 1978 (H. Kager, 1980). It is controlled by the command language DIRAN (DIRective ANalyser). Since that time ORIENT has grown considerably to become now a powerful and universal tool for photogrammetric point determination at the Vienna Institute of Photogrammetry and Remote Sensing.

1978 the QUICKPLOT capability has been programmed, the first part of the PLOT module, as a necessary means for error detection.

1980/84 - step by step - the concepts of data snooping and of robust estimation have been implemented to enable automatic detection and elimination of gross errors.

1982/83 graphics facilities have been added to the PLOT module to enable input from digitizer and output on graphics screen or plotter.

Since 1983 a rigorous solution for the integration of geodetic polar point measurements (direction, distance, zenit distance or any subset there of) has been implemented.

The user guidance system with a new prompter concept added a quasi-menue technique, which takes into account different levels of experience of ORIENT-operators. The user is guided and instructed step by step from the beginner's to a professional's level, directly communicating with ORIENT via the command language DIRAN. So the user will not be fatigued by boring menues as soon as he does not need them any longer.

In 1985 the module CALCULATE has been added which enables the user to compute directions, angles, distances, traverses, and even staking-out-data for groups of points entering just a few commands.

1988: Using the Prompter-Conzept, a graphical lerning-programm was conceived to help the ORIENT-beginner to learn the necessary theoretical basics.

Since 1989 approximative values for the orientation elements of images and models can be provided by the module APPROXIMATE.

1990 new sensor-geometries became handleable: array- or rotating line scanners can be handled modelling the flight trajectory (orbit) in the adjustment process.

Since 1994, joined cubic polynomials (e.g. Splines or Akima-curves, become integrated into block adjustment. By this, free-form-curves may be used as well for image as model orientation. They may serve as control-lines as well as tie-lines. The reconstruction of unknown free-form-curves with photogrammetrcal spatial intersection is another astonishing feature.

1999 brings a revolution in the handling of ORIENT: ORPHEUS as digital multi-image comparator as well as GUI (graphical user interface) for ORIENT.