Basic references in remote sensing are listed in [1] to [o] . 
Sensor development has since proceeded very rapidly for very special and 
mostly classified applications loj. Technology has therefore progressed 
faster than its possible application. This trend is even accelerated 
through the development of earth resources satellites HE 21. For this 
reason most earth science oriented professions are now taking a closer 
look as to what remote sensing may offer to them [12]. It may therefore 
be understandable why many commissions of the International Society of 
Photogrammetry have started to show an interest in remote sensing, and 
this is as it should be. Remote Sensing systems,just as photography of- 
fer imaging problems which should be covered in commission I. The techno- 
logy of evaluating this type of imagery is the concern of commission II, 
the results which can be attained by practical tests are subject of com- 
mission IV, the application lies mostly in the realm of commission VII, 
and there is lots of new terminology to be decided on by commission VI. 
Since there has not yet been time enough to establish firm ground in any 
of the above tasks certain overlaps may have to be tolerated in the interest 
of a faster progress. In this respect the presidents of commission IV and 
II are to be commended for treating their problems in remote sensing joint- 
ly. These questions are a direct result from the properties of the remote 
Sensors. 
2. Sensors 
Sensors may usually be characterized by four properties, which control their 
applicability: 
l.) spectral range 
2.) sensitivity within the spectral range 
3.) resolution as a function of naturally available contrast 
and of the contrast transfer 
4.) geometrical fidelity