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INTRODUCTION 
The digitization of information pertaining to the ground and subsoil makes 
it possible to build up a living and dynamic information system having the 
following advantages : 
. Centralization of urban data, 
. Easy and quick access to information, 
. Continuous updating of information, 
. Possible connection with varied administrative information. 
The different elements that have been acquired must be organized to allow: 
. the characteristics of the acquisition process : origin, 
scale, accuracy, to be kept 
. various and fast access methods to be used, 
. the link of geographical item with an administrative 
identifier, 
. updating. 
Thanks to the coherent structure of the information taken into account 
the MATRA DEMETER system contains the necessary tools to achieve these 
objectives. It provides all the functions required for : 
. Data acquisition, 
. Data management, 
. Data utilization. 
DATA ACQUISITION 
  
Depending on its origin, the data can be acquired by three sub-systems. 
These sub-systems use a same code catalog that can be defined by the user. 
Each of the data acquisition codification software check the acquisition 
control table to valid data before data base storage. 
DEMETER T P 
DEMETER T P is a topographic sub-system which pogs in computes topogra- 
phic observations as well as the different types of standard point 
calculations. 
This sub-system collects the measurements which are carried out by using 
standard conventional or electronic tacheometers and theodolites. 
Main computing functions are : 
Geodesy and triangulation : 
* resection * intersection * countersection * determination of average 
azimuth | * coordinate transformation. 
Polygonation and survey : 
* traversement * determination of control points, 
* high accuracy levelling * conversion of polar coordinates into rectan- 
gular coordinates (data acquired with  tacheometer or theodolite and 
E.D.M.) 
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