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The database of this network is numeric and must be 
found and elaborated in a graphic form so as to be the 
same as that of the existing cartographic Road 
cadastre, which remains linked to the national geodetic 
network, with a precision relative to its scale (generally 
the scales are large, 1:2000 or 1:1000). 
The basic cartographic structure of the Road cadastre 
is thus made up of the network of the road axes and the 
cadastral maps inserted in the national geodetic 
network. 
The maximum error that is tolerated depends on the 
involved elements and the need that it be the same as a 
map, by means of a numeric database plot. 
Each road will be qualified by means of a series of 
attributes that integrate the simple geometric 
information and that are defined in the deign phase of 
the G.I.S. project, also based on the nominal scale. 
For dual-carriage-ways it is necessary to memorize the 
center-line of each carriage-way, in order to have 
correct information on the plano-altimetric trend. 
It is also necessary that the cartographic production 
respects some conditions that are particularly useful for 
the finality of the information system. 
First of all, the roads that connect and cross built-up 
areas must always be extended inside the same, so 
that the axes are not continuous. 
At the intersection of each road with the outskirts of the 
built-up area a node will be identified that will allow the 
road to be assigned an attribute of urban or extra- 
urban. 
Inside the urban areas, with the exception of the case in 
which the G.I.S. is specifically orientated for the 
maintenance of the road network (survey scale > 
1:2000), it is sufficient to show only the fundamental 
roads (of the eventual motorways that cross urban 
areas), guaranteeing, however, the continuity of the 
road network, that is the presence of a connection 
between all the roads of the urban area. 
The element lists to be memorized in the cartographic 
supports of the G.I.S. must be compiled with regard to 
the information systems scale. On a large scale 
(1:1000-1:2000) certainly some elements (e.g. guard 
rail, new jersey, horizontal signs, etc.) can be 
excessive and not coherent for the level of detail of 
lesser scales. In any case the designer of the G.I.S. will 
define the nominal scale for the cartographic 
representation and its Information content. 
Particular attention should be given to the intersections, 
which must always be identified with a network node 
and described by an attribute that defines the 
characteristics. 
For the greater scale, from 1:2000 up, which are ideal 
for the realization by G.I.S. aimed essentially at the 
problem of maintenance, it is useful to extend the 
concept of area also to the roads, normally linear. This 
is a significative evolution of the information level of 
numeric cartography, which, associated to the road 
stretch represented by the attribute “aerial development 
”, other than the traditional “linear development”, gives a 
further important contribution to the knowledge of the 
infrastructure. 
Naturally, there must be no solutions of continuity in 
correspondence to intersections, bridges, tunnels, or 
other works or infrastructures that border the road, such 
as buildings, walls, special areas, etc. 
In the memorization and representation of the road 
network, finally, we must remember that the viability 
areas are complementary to the definition of the areas 
of the urban districts in the same way as they interface 
with the hydrographic network. The representation of 
the road network must be in keeping with that of the 
hydrographic area and urban areas, in such a way that 
the map offers no continuity solutions. 
Other than the increase of the specific information level 
“communication”, the production of maps should 
guarantee complete and detailed information on the 
“border conditions” of the road system, by means of the 
memorization of all the elements that are useful for the 
definition of the interferences and correlations between 
the territory and road system. 
The territorial elements to be memorized are defined in 
the deign phase of G.I.S. and required by the company 
who will produce the maps with specially designed 
regulations. 
It is a good general rule that the memorization takes 
place at the same time as the “restitution”, immediately 
associating to every recognized element its respective 
code. 
The elements are generally subdivided, other than for 
territorial sectors, in relation to the code system, which 
can be divided into the following three groups: 
• homogeneous linear elements, represented by a 
polygon and identified by means of an alphanumeric 
code that defines the type; 
• linear elements that border areas having different 
characteristics, which can be defined by means of 
the composition of the identification codes of the 
areas; 
• point elements, represented by points or symbols 
anchored to points, defined by a code that defines 
the type. 
The border elements, of course, are those that need a 
code that is more articulate and complex, which, on the 
other hand, corresponds to a greater information 
content. 
It is first necessary that the border linear elements are 
orientated, in a way that defines the area to the right 
and left. Furthermore, the areas must be described from 
the topological point of view (e.g. “asphalt surface ”, 
“pavement”, ....) and from their spatial collocation (“in a 
tunnel”, “on a viaduct”, etc.). 
Each area, therefore, will be defined by means of an 
alphanumeric code that clearly indicates the typology 
and collocation; every border linear element will, 
instead, be defined by means of a composite code, with 
a pre-established succession, of the two identification 
codes of the border areas.