THE INCORPORATION OF THE MAPS OF THE ATLAS OF THE ITALIAN BEACHES IN A GIS SYSTEM

N. Corradi, A. Botta, A. Bozzano, M. Ferrari

DIPTERIS University of Genoa (IT)

Abstract
We here present a coastal GIS based on the themes of the Atlas of the Italian Beaches, and provide information of a cartographic and morpho-sedimentary nature for the entire coastline.
The creation of this product involved the development of a GIS system and the organization of the relative information to make the data usable by those legally responsible for the administration of the coast and those who have an economic interest in it.

Introduction
The coastal strip is an invaluable natural system that is characterized by a particular, delicate natural equilibrium. Over the course of many years enormous urban and industrial structures have been established for military and economic purposes with consequent widespread anthropization. Italy is a notable case of a remarkable coastal environmental that requires a systematic study of its natural processes and anthropic activities to produce a detailed picture that can serve as the basis of a strategy for its protection and defence.
It is therefore desirable that all researchers and planners in this area pay close attention to the problems facing the coastal strip and to providing the correct interpretation and presentation of the data to all governmental and commercial interests, particularly given the ever increasing anthropic load that this narrow strip of territory, between the sea and the land, faces under the ongoing "oceanization" trend.

The Atlas of the Italian Beaches
Research that began in the 1930s has produced a great number of monographs and maps. The knowledge acquired up to the end of the 1990s is presented in The Atlas of the Italian Beaches (financed by CNR and MIUR), the innovative product of a multi-disciplinary effort over the preceding ten years and the first example of such an atlas dealing with the Mediterranean. The Atlas is intended as a tool for those engaged in the management of the coastal strip, specifically those working for public agencies, or involved in planning, tourism and maritime development; in other words, all those people who use the coastal strip or are engaged in marine and coastal research. The Atlas, based on the 1:100,000 cartographic scale of the Istituto Geografico Militare, provides information on anthropic and natural activity and the hydrological and sedimentary dynamics of the coast and its adjacent watersheds.

Fig. 1 Particular of the Atlas of the Italian Beaches (map N°. 272 Gela)

Management Information
The Atlas of the Italian Beaches provides an overall view of the national coastline, condensing thousands of pieces of information and data, which can make it difficult to extract or use a single datum. The paper version, by its very nature, only permits a graphic representation, despite the great costs and human resources expended on its acquisition. In terms of the evolution of the treatment of geographical and territorial information on the part of public and private users, ever more accessible due to computerization, The Atlas of the Italian Beaches, notwithstanding all the useful data it contains, is not presented in the best format for its maximum use. Perceiving that inserting the data on a GIS platform would permit greater use of the contents, The Ministry for the Environment and the Protection of the National Territory considered it opportune to adopt this system, giving responsibility for doing so to DIP.TE.RIS of the University of Genoa. The production of this GIS has provided the first computerized system totally dedicated to the Italian coastline. With this GIS technology, every user authorized by the Ministry will be able to access the geographic information and utilize the data on it from any terminal. In other words, every user will have the possibility of visualizing, exploring, checking and spatially analyzing the data on the Italian littoral and inserting other information to augment its scope.

Base Cartography
As the original scale of 1:100,000 of The Atlas had to be maintained, the cartographic material was suitably adjusted to provide national cover. As opposed to the paper version, for which the cartography of the Istituto Geografico Militare (IGM) was used, the new project adopted the cartography of the Istituto Idrografico della Marina (IIM). The adoption of this new system made it possible to accurately draw the coastline from the reliefs of the IIM or other equally valid sources. The information on the littoral was then further supplemented with data on the morphology of the submerged beach, essential for understanding the sedimentary dynamic. Furthermore, hundreds of trigonometric points, obtained from the geodetic and topographic measurements of the IIM and essential for the production of a map, as they represent the anchorage points, were inserted on the vectoral charts of the IMM.
To further enhance the quality of the maps, other information, such as the sites of lighthouses, prohibitions on mooring and fishing, etc., were included during the vectorization of the nautical charts. In all, 108 pages of The Atlas and 49 charts of the IIM, on a scale of 1:100,000, were transposed to and homogenized to provide cover of the entire coastal strip. The original atlas consisted of 108 maps on an IGM scale of 1:100,000. The geodetic system adopted was the International Ellipsoid oriented on Rome-Monte Mario (Rome 1940) and Mercator's Universal Transverse Projection and the coastline was defined as the mean sea level.
The cartographic basis of the new atlas is the 1:100,000 series of the IIM, consisting of 47 charts of the national coastline and two charts of the eastern coastline of Corsica (which include Italian territorial waters). The geodetic system used is the International European Datum 1950 (ED 1950) and the coastline is defined as the high water mark.

Figs. 2 & 3 Maps of Italy east & west of the Rome - Monte Mario meridian

Project Structure
The production of this computerized geographic system involved a numberr of decisions to guarantee the highest quality. The decisions were based on two fundamental criteria: the importance of the data and system flexibility. Considering the extent of the area included in the work it was necessary to give an overall view of the coast and, at the same time, evaluate every single datum (of the thousands inserted) after verifying its importance and correctness through accurate bibliographic research and, when necessary, field investigations.
It was necessary to structure the project so that any request to the system for a single datum (beach, defence work, bottom slope, etc.) would provide detailed information on the single datum or on the surrounding area in the briefest possible time. The second criteria adopted during the planning stage was to make the information package as easy to use as possible and the creation of extremely simple and flexible layers made it possible to organize the basic elements of the system in the simplest manner.

Methodology
The first phase of the work was the vectorization of the cartographic base, done at the Istituto Idrografico della Marina Militare in Genoa using the "Microstation NT Bentley" computer programme and "Pangea s.r.l." software modules.
The transfer of the information to a digital format was done as follows:

The digitalization of The Atlas of the Italian Beaches did not require rasterization and superposition of the paper charts, as was necessary with the nautical charts. To digitalize the themes of The Atlas on a numerical basis it was necessary to visualize the digital nautical chart with AutoCAD® software (with the file downloaded in .dxf exchange format) and to work directly on that.
To insert the themes in the AutoCAD® file it was decided to produce a symbol bank that could be easily copied and positioned in the appropriate places to give the graphic elements uniformity.

Fig. 4 Particular of the Atlas of the Italian Beaches on GIS

The mapping of sediments was carried out on the basis of the morphology of the bottom and experiments on sample areas with bibliographic solutions. The charts were vectorized using AutoCAD® software to be able to acquire data from the ArcView® GIS system, the file of which was exported with .dxf. The .dxf files of the themes of The Atlas and the nautical charts were loaded on ArcView® as themes (Add Theme) and each of these was converted to Shapefile. The final result was the creation of numerous files in Shapefile format, each one containing different layers. In the creation of individual projects the necessary Shapefiles were taken into consideration and their specific graphic characterization fixed.

Conclusions
The final product is characterized by the great quantity of information inserted in it and the choice of a very simple system permitting elasticity and easy access.
The choices made had two major aims:

Maximum diffusion of the system: to ensure the maximum diffusion of the atlas it was essential to make it as easy to use as possible, assuming that the user would not necessarily have particular expertise in computer technology or all the themes presented (geology, engineering, etc.). The insertion of the product in the computer system of the Ministry required that it be simple and versatile to be a useful tool in making decisions involving the coastal environment (knowledge of the territory, critical analysis of coastal planning proposals, evaluation and management of emergencies).
Future applications: the simple design makes the product a useful cartographic basis for the future addition and integration of other themes (sedimentological, biological, regulatory, etc.)
The accuracy of the cartographic basis of The Atlas (Carta dello Stato, IIM) and the coastal themes described make the present work unique at a national level and it is hoped that the future will bring the introduction of new data.

References