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including the data collection, the geometric correction, the 
structuring, the editing and the drawing. 
In order to assure the integrity of the information, a local 
network Ethernet connecting six nodes was installed. Each 
node is doted with database servers (the total storage 
capacity is 76 gygabytes) The operating system is 
managed by a central server VAX 4000-400, Double 
System, 160 MB RAM per each one, with peripherals 
devices for reading, storage and printing. 
4. THE BASIC TASKS 
The new mapping production includes until now the 
1:2.000, 1:10.000 and 1:25.000 scales. The conceptual 
framework inherent to the digital cartography focus the 
attention to the construction of the data infrastructure 
required for the different users to the implementation of 
Geographic Information Systems. They need, by definition, 
reliable, high quality, current and topologically structured 
data, organized in a flexible model. 
Hence, IGAC defined as the core of its function the creation 
and maintenance of the national topographic database. 
Cartographer's thoughts were changed because of the 
technology and the client's needs. 
Both, the implementation of the new production flow and 
the creation of the data base started in August, 1994, after 
developing some basic activities: 
l. Analysis of user's requirements and definition of 
the modernization guidelines. 
2 Design of the basic components and the technical 
specifications of the new system. 
3. Acquisition, installation and testing of the 
equipment. 
4. Training. 
s. Design of the IGAC database (data organization 
and data structure). 
6. Definition of the methodologies and procedures 
for the new topographic and thematic mapping 
production and for the digitizing of the analog 
cartography. 
7 Testing of the new production flow in a pilot 
project. 
5. THE DATA MODEL 
IGAC has defined a digital data model that includes the 
Whole objects or features needed in the different 
departments to elaborate their products. Thus, each 
fechnical area adds (or integrates) its own data (or 
attributes) over the topographic data which act as a basic 
framework. 
It was defined an unique feature's classification system, that 
divides the universe into classes or themes, which are 
divided, again, into groups. For each scale, it was selected 
the list of objects relevant to each group, described its 
geometry and attributes, identified its relationships and 
defined its sources, collection and processing rules and 
representation standards. 
6. THE WORKFLOW 
The current IGA C's photogrammetric production line is as 
follows: 
: Definition of the data model 
- Creation of the project (scale, coverage, inputs, 
topology rules) 
- Establishment of the different access levels 
- Users definition. 
- Preparation of the project (model orientation, 
creation of extracts and local storage units). 
- Restitution (3D data collection) 
- Topology Building and on-line editing 
- Geometric and logic correction of elements 
- Attributes adition 
- Preparation of graphic outputs 
- Final Printing 
- Storage in the data base 
This workflow is done in two different groups - Restitution 
and Editing - and involves some quality check points (and 
plots) including the final position's accuracy test. 
7. THE RESULTS 
One and a half year after going on with the new system, it 
is clear that the current maps are different. Their quality 
and usefulness are without any doubt better than the 
previous. The photogrammetric and cartographic work is 
no more the same. It may be more exigent but indeed more 
gratifying. 
The IGAC database has started to be feed. IGAC joins its 
own capacity and also put work out to contract with private 
companies to accelerate the process. The main achievement 
has been the production of seamless digital maps of eleven 
cities (600 km?) at 1:2.000 scale. Those cities majors have 
obtained the digital framework required to accomplish their 
management and planning activities. The completion, 
maintenance and updating of the topographic database are 
now the duty. Several tools will help IGAC to do it 
efficiently: the super-imposition modules, both 
stereoscopic and monoscopic, offered by the new system. 
The IGAC productivity is, nowadays, lower than the 
‘ obtained with the traditional mapping flow. It seems 
521 
influenced by the following factors: 
1. The work is much more complex now. 
2 The people's accomodation to the changes are no 
so fast as you want it. 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B4. Vienna 1996