For answering questions like "where are we?" or "how
to go there?" we need geoinformation.
Geoinformation is also used for making maps. Geoinformations characteristic is its combination of
geometry (position, size ...) and thematic information (e.g. building, forest etc.).
The analytic way to describe geometry of geoinformation is the coordinate-method.
coordinate systems used for geoinformation are called coordinate
reference systems (CRS).
Different task often also use different CRS. e.g. in construction engineering, national map making,
cadastral, presentations... .
For many tasks, you need geoinormation from different sources. Often, they are hold
coordinate reference systems. to use these different datasets together, you need to unify the
coordinate reference system. Read e.g. [Voser 1996 ]-
For combined usage, geodatasets need to be in the same coordinate reference system
For the hamonization of coordinate refernece systems, you need various information
- knowledge about the coordinate reference
systems of your datasets and your needs
- the relationships between the coordinate
reference systems, (methods and parameters...)
- tools for manual or automated coordinate
reference system change. Read e.g. [Voser 1997
(Arcinfo Application BEZUG ), Voser 2007 ]
Even nowadays (2017) it is difficult to find information of different coordinate refernce
though there exist offical collections.and many geospatial applications support offical crs and have
databases with parameters for change.