Tunisia has launched the GEONAT program aiming at implementing a national geomatic system since 1998, focusing on the development of a digital-based infrastructure, establishing a common referencing framework for all the territorial managers, in order to frame the developing efforts already started, and to establish an exchange network between the different sector-based GIS.

The adopted process, for the realization of the national geographic information system, consists of dividing the program into two subsets :

• A subset focusing on small scales mainly used for planification and territorial development.
• A second subset focusing on large scales particularly for urban operators.

The "small scale" component covers the whole Tunisian territory. It shall serve as a work plan for all the parties involved.

The component, conducted by the Secretariat of State for Informatics and focusing on urban areas, concerns essentially urban operators, municipalities and network dealers, based on land aspects.

The transition from a range of scales to another (precision) is reflected through the definition and the determination of all the objects, elements and presentations to be taken into account.

The first action performed, related to the urban component, has focused on the realization of an Urban Network Database (BDRU), which has allowed a better evaluation of the feasability of common actions to be carried out between several partners, and has made the different parties involved much more aware.

A second action, which is in the process of being realized, focuses on an Urban Municipal Database (BDMU), which aims to be global, in other words it concerns all information linked to the space contained into a local territory.

A third action shall focus on the definition of a Property Information System (SIF), starting from digital geographic base.

The concept of durable development contributed greatly in the evolution of the vision of the territory. It became then obvious that the control of its complexity requires the use of powerful and well-adapted methods, techniques and tools for analysis. The territorial managers are confronted with a phenomenal growth of information needs related to the territory knowledge, management, development, protection, and after all, to the rational use of the territory and its resources. Such needs aroused the implementation of various techniques of data acquisition on the territory (sensors of remote detection, digital cameras in photogrammetry, GPS receivers in geodesy, total stations with electronic pads of note in topometry), giving public and private organizations a huge amount of data, faster way with a better quality and at the least cost.

Besides, the convergence of considerable computer progress and of the development of geographic data acquisition techniques, gives birth to the digital mode of territorial information management, materialized by the Geographic Information System (GIS). As a matter of fact, this new mode of management removed the geographic information from one of its particular representations (the map) in which it was confined, to make it reproducible and thus more accessible, increasing its capacity of use in different applications.

In Tunisia, projects have been launched, in the last few years, aiming the implementation of Geographic Information Systems (GIS) in several ministerial departments and national organizations (Such as the departments of agriculture, environment and territorial development, economic development, and organizations like Tunisie Telecom, the Urban Agency of Grand Tunis, etc.). In the light of the aforesaid experiences, one can notice that these sector-based GIS, taken individually, are substantial and respond to real users' concerns. Yet, they are often non-compatible between one another although they relate to the same territory. This lack of coordination causes redundancies and duplications in data acquisition as well as in data dissemination. It also restricts considerably their interchangeability, thus generating high costs to the public community.

Recently, the development of a digital-based infrastructure at all the territory levels, setting up a common referencing framework, became an urgent need for the purpose of framing the ever-growing efforts already started and the establishment of an interchange network between the different sector-based GIS. In addition to the adoption of national standards, human resources training in the field of Geomatics and the clarification of legal stakes are so many activities providing a substantial support to the perpetuity of the national geographic infrastructure.

In order to organize all these actions and to get a clearer vision, the Ninth Economic and Social Plan mentioned a national program named GEONAT (national geomatization) aiming at endowing the country with a digital-based infrastructure in geographic information, and allowing the different interveners to administer properly the territory for a durable development.

The main objectives of this program are  :

1. The definition of a common geographic system of reference and the constitution of a digital geographic base applicable to all territorial levels ;
2. The development of standards relating to the structuring, production and interchange of geographic data ;
3. The realization of a series of digital geographic databases with public interest ;
4. The implementation of a developing methodology for GIS to support the design and achievement of different systems ;
5. The clarification of legal and institutional stakes relating to property, security and dissemination of geographic data, which are crucial issues for the development of the geographic information market ;
6. The promotion of necessary human resources, covering public sector, private industry and university and professional training.

Given the specificity of both small scales and large scales, as well as the particularity of applications relating to every set of actions, it has been decided to divide the program into two main parts :

• The first part, using small scales and covering all the national territory, targets planification, environment and territorial development where a series of topographic databases, according to different scales, has already begun.
• The second part, concerning urban areas where the use of large scales is compulsory, concerns the planification and the management of the urban environment. The main characteristic of this part of the program is the repeatedness which has two dimensions : that in passing from a conglomeration to another, and that in which users can be regrouped in homogeneous sets with same needs, at the level of information collection and its capture, or at the level of the design and methods of development. A typical example is an Urban Network Database at level one and level two. This base is a common-core syllabus for network managers, and will serve for study projects and on-site activities. It will also be useful for municipalities for the planning of interventions and the coordination between public street network users. Another example is an Urban Municipal Database which is common for all municipalities.

In application of the above-described approach, with respect to the urban zones, the following actions have been started :

1. A Digital Cartographic Base

2. An Urban Network Database (BDRU)

Urban networks, particularly underground networks, cause huge problems because of their evolution and their maintenance if they are unsuitably controlled and managed. This is the reason why GEONAT project counts among its priority actions the constitution of the five underground urban networks Database, namely Electricity, Gas, drinkable water, waste water, and Telephone networks, so as to :

• Provide national companies (Operators) with a study and a planning tool for the future extensions of their networks and to better target the interventions of repair and maintenance.
• Allow local communities (municipalities) to fulfil their role of coordination and planification as soon as interventions on public street networks are concerned.

This BDRU Database includes plans of the different underground networks (level 1 and level 2) and the main works constituting these networks. All this is reported on the digital cartographic base on a scale of 1/1000.

This action started with a prototype concerning a zone of the Grand Tunis and gathering in the same workshop, engineers of various operators, supervised by representatives of the Urban Agency of Grand Tunis.

This step of prototyping led to meet several objectives and brought the following main actions :

• The training of engineers to use the tools of geographic data acquisition and processing, particularly the Geographic Information Systems (GIS).
• The awareness raising officials through the demonstration of real implementations.
• The stimulation of a fair competition between different partners, particularly because they work in the same place.
• The observation that the layouts recaptured from plans are sufficient for the needs of decision-making, but insufficient at the level of the exploitation for the exact location of networks.

3. An Urban Municipal Database (BDMU)

In view of the first experience results related to the prototype of the Urban Network Database (BDRU) and the adherence of all partners to the used approach on the one hand, and the interest expressed by the Head Office of local public communities and by a group of municipalities on the other hand, it was decided to expand the Urban Network Database so as to make it a more complete and more general system at the disposal of local communities (which gives birth of the Urban Municipal Database).

In addition to operators’urban networks, this Database comprises lighting, roadsigns and urban transport networks, as well as public roads, land plots, buildings and green areas.

As BDRU prototyping experience was very useful in terms of information, the same approach has been applied for the Urban Municipal Database, for which a prototyping phase has already begun, involving seven municipalities. The first remarks are :

• The motivation of municipal agents ;
• The comparison of several GIS products, in order to classify them according to their applications.

4. A Property Information System (SIF)

The Land Property Information System, based on land plots, turned out to be a necessity during the definition of the Urban Municipal Database (BDMU). This orientation was motivated by the availability of the digital cartographic base on a scale of 1/1000, which was taken as a basic element to build the Property Information System.

As a matter of fact, the Property Information System consists in adding a property layer on the digital cartographic base through the identification of the public and private titled possessions and the untitled properties, along with the clarification of their status as well as :

1. Geographic coordinates ;
2. Sets of attributes allowing land property identification and evaluation.

In this respect, a prototyping phase has already started.

The concern is to set up procedures, mechanisms, standards and tools, in order to reach the objectives assigned to GEONAT program and more particularly :

• To give to all potential users a single geographic system of reference achieved through a series of Digital Cartographic Databases covering the totality of the range of scales, starting with small scales, then large scales, to very large scales, while defining the transition mechanisms from a series of scales to another, as well as the data dictionaries for each database.
• To define mechanisms, procedures, standards and methods of supplying and exploiting the Urban Network Database (BDRU) and the Urban Municipal Database (BDMU), particularly the charters between partners.
• To define interfaces and mechanisms of transition from the BDRU to specific Geographic Information Systems of operators.
• To implement a group of standards, methodological approaches and procedures, to promote the development of the geomatic sector, while respecting coherence and complementarity.

Mr Mohamed BEN SASSI

Director of International Cooperation and Innovative Projects

Secretariat of State for Informatics – Prime Minister – Tunisia.

Address : N°16, street 8010, Montplaisir, Tunis, Tunisia.

Telephone : (216 1) 790 885

Fax number : (216 1) 846 865