what make up the geodetic information system of a country?
Here in the US the National Geodetic Survey provides:
1. a network of Continuously Operating Reference Stations (CORS) and makes their data available for download.
2. the OPUS Positioning system where the user can send in collected static data and receive a resolved position.
3. a catalog of the geodetic positions of the CORS and the many passive marks that have been established.
4. Updated Geoid models that relate the ellipsoidal heights to orthometric elevations
5. Software tools for converting positions from one geodetic datum realization to another.
6. . . . . . . .
At the heart of any counties system should be the fundamental definitions of the horizontal (geometric) and vertical datums and possibly tidal datums associated with some form of easily accessible governmental documentation of what those parameters are. Depending on a variety of conditions some countries could certainly have reasons for managing several different datums such as the six vertical datums defined for the U.S. Addition specific definitions for any plane coordinates systems they might what to use.
Then there's the development of a user friendly interface to some database that provides geodetic positions/heights, station descriptions and assorted geodetic elements (geoid heights, positional/height uncertainties, legacy positions/heights, gravity information etc.) All of which need to be managed all the individual observations (GPS vectors, leveling, horizontal directions, distances, astronomic observations etc...) required for contemporary and future adjustments.
The list goes on but there's a good place to start.
