The high precision leveling network was set up between 1950 and 1971 and at the beginning consisted of 13000 benchmarks indicated along the roads of Italy. Other leveling networks belonging to the Cadastre, public entities and research institutes are connected to this network. At the moment an important project is being carried out; it consists of remeasuring the existing lines and setting up new ones, in order to have more than 20000 benchmarks. Elevations refer to 4 relief systems: Genova 1942 for Continental Italy, Cagliari 1965 for Sardinia, Catania 1956 for Sicily, Lampedusa 2005 for the Pelagie Islands.

Monographs  of benchmarks are for sale.

Buy ONLINE: Geoproducts

How to buy online: read How to use the geographic search browser and How to buy a leveling benchmark

In the geographical search engine, leveling benchmarks are represented by red or blue round icons. These different symbols are described below:

Leveling benchmark measured after 1996

Leveling benchmark

Monograph of benchmarks consists of a pdf sheet of useful information that will be send to the costumer. In each information sheet are indicated:

• name and specification: name of the point location, a specification can be added in order to better identify the place of materialization;
• number: the benchmark is identified by an alphanumeric code consisting of 3 different parts separated by underscores: the first part (4 alphanumeric symbols) indicates the line the benchmark belongs to, or the nodal point when the first symbol is “N”; the second part (3 alphanumeric symbols) indicates the line deviation (if existing), the third part (4 alphanumeric symbols) indicates the sequential number of the benchmark on the line.
• administrative information: nation, region, province, municipality where the benchmark is located;
• cartographic elements: cartographic elements of the benchmark in the following series: sheet at scale 100.000, map at scale 25.000, sheet at scale 50.000, section at scale 25.000.
• symbols: up to 4 different symbols for each benchmark; a graphic symbol (see the table below) indicates the benchmark’s materialization, then the height up to 0,1 mm. and the description of the exact location of the symbol.

HORIZONTAL symbols

Symbol	Description	Height reference
	I Category (Nodal) – Cast iron manhole	Horizontal planes tangent to A,B and C ledges
	II Category (Fundamental) – Cast iron manhole	Horizontal planes tangent to A,B and C ledges
	III Category – Cast iron manhole	Horizontal planes tangent to A and C ledges
	IV Category – Concrete catch basin	Horizontal planes tangent to C ledges
	V Category – Cast iron manhole	Horizontal planes tangent to C ledges
	Bolt	Horizontal plane tangent to the superior part of the tonic surface
	Nail	Horizontal plane tangent to spherical C ledge
	Circle	Central point of the Circle (it can be measured by half sphere)
	Universal benchmark (horizontal)	Horizontal plane tangent to spherical C ledge
	Metallic disc (lead)	Central point of the Circle (it can be measured by half sphere)
	IGM benchmark	Central point of the Circle (it can be measured by half sphere)
	Horizontal symbol	Described in the information sheet
	Horizontal plan	Described in the information sheet

 VERTICAL SYMBOLS

Symbol	Description	Height reference
	Shelf	Horizontal tangent plane to half sphere
	Barrel-shaped mark	Central hole
	Old mark	Central hole or line
	Mark of other administrations	Described in the information sheet
	Plaque with line	Line or other carved symbol
	Mark with small cylinder	Central hole
	Universal benchmark (vertical)	Central hole

• kilometric progression: indicates the kilometric distance from the first Nodal point of the line;
• year of measurement: when the height was established;
• year of the last survey
• IGM95 connected point: if linked with an IGM95 point;
• connected leveling benchmarks: planimetric/altimetric connection with vertexes of classical network or with leveling benchmarks;
• description sketch: floor plan or perspective drawing representing the vertex and its surroundings;
• geographic coordinates: expressed in sexagesimal format within the ETRF2000 and ROMA40 geodetic systems;
• one or more pictures of the point;

The following monographs are available:

• LEVELING BENCHMARKS of the modern high-precision leveling network
• OLD NETWORK LEVELING BENCHMARKS of the old  high-precision leveling network