Positioning
Positioning establishes, by means of coordinates, a point's most exact position possible. Positioning is realized by
the application of methods developed in the field of geodesy. The accuracy of the positioning depends on the means invested.
The accuracy can be very high, in the range of millimeters compared to a reference. Nowadays the accuracy is not limited
by
technical obstacles anymore. It's enough to pay the price! In the GIS context, the optimal accuracy referring to the
scale
of the phenomenon which is studied has to be obtained. The conventional positioning tools are surveying and photogrammetry.
For a couple of years now, there is the satellite positioning system available, provided by the United States Department
of
Defense. The accuracy is 5 to 10m in direct mode using a low cost receiver, or in the range of centimeters using a more
expensive
differential receiver. Since 2008 there is the European system named Galileo.