Technologies and spatial data for modern land governance. Tools to support the cadastral reform

9 *Flavio Celestino Ferrante **Gabriele Garnero Technologies and spatial data for modern land governance. Tools to support the cadastral reform Keywords: Cadastral Reform, Cadastral Cartography, Real Estate Values. Abstract This article outlines the methods and activities, in the field of mapping, in support of the important process of renewal of the entire cadastral system. It describes the technology and spatial data currently available that can assist in setting up complex issues of reforming appraisal system and, more generally, in the processes against tax evasion in real estate. INTRODUCTION The recent introduction of the IMU (Municipal Property Tax) has again highlighted the vexed question of inequality existing in cadastral appraisal systems, recently pointed out by the Director of Agenzia del Territorio (hereinafter AdT) in hearing at the Chamber of Deputies, VI Finance Committee of 13 September 2012; the hypothesis of a radical reform of cadastral appraisal systems is becoming increasingly significant. In the context of the current debate, below are the principles and criteria on which it is assumed to base the revision of the cadastral appraisal system laying out: use of statistical functions expressing the relationship between the market value, location and positional and building features for each cadastral destination and for each geographical area; use of per square meter as a measurement of urban real estate. As can be seen from the principles and the above operational criteria, the data concerning the geolocalization of properties in relation to the urban context and to the characteristics of manufactured building play a fundamental role in the revision process, for the correct determination of cadastral appraisal systems and for the time and resources needed for their acquisition. To effectively address these challenges, we need a precise, complete and qualified knowledge of Italian real estate. It seems appropriate to point out, already in the introduction, that, regardless of the technology platform which will be illustrated below, the effectiveness of the results depend strongly on the data quality (completeness, consistency, accuracy, updating, positional accuracy, etc..) and especially by their degree of correlation in various archives. This paper aims to offer a contribution to the documentation and comprehension of geo-referenced data of the real estate in Italy and processing and analysis tools, both concerning the hypothesis of a reform of the cadastral appraisal system and more generally the fight against tax evasion in real *Revenue Agency - Central Directorate for Cadastre and Cartography Area Manager for Cartographic Services Section (flavio.ferrante@agenziaentrate.it) **University and Polytechnic of Turin - DIST Interuniversity Department of Regional and Urban Studies and Planning (gabriele.garnero@unito.it)

10 Flavio Celestino Ferrante and Gabriele Garnero estate, both in relation to the regular institutional Agency s activities recently incorporated in the Agenzia delle Entrate. In the first part of the article we will discuss AdT data and the technologies of the Agency and then the data and technologies outside the domain of the Agency, but closely related to and interoperable with the first one. DATA AND TECHNOLOGIES OF AGENZIA DEL TERRITORIO The Agenzia del Territorio is today a complex and dynamic body, characterized by the massive use of advanced technologies that allow communication with remote users through web platforms. The level of computerization achieved in data updating is high, especially in the selection and development of innovative technological solutions allowing real-time updating of the cartographical, cadastral and Real Estate Advertising archives in respect of the total transparency of administrative procedures. The AdT, strong in its roots and conscious of the need of constant updating, now puts at the service of the Country its information, skills, knowledge and know-how for the implementation of a modern land governance. In order to develop important and essential synergies with other public bodies and agencies, the Agency believes in its mission of assuming the role of inter-institutional mediator in order to facilitate the information flow, its sharing and the development of innovative technological solutions (Garnero, Cogoni, 2012; Ferrante, 2009). The real strength of the organization is the asset of knowledge and data concerning the Italian real estate, inherited from the previous government departments: Catasto, Servizi Tecnici Erariali e Conservatorie dei Registri Immobiliari, together with an extraordinary asset of expertise of its employees. The information asset managed by the Agency is divided into three systems: the cadastral information system, with more than 82 million parcels of the land cadastre and 63 million of real estate units, described in their technical and census characteristics and enriched by the plans of each unit, a prerogative unique in Europe; Sistema informativo della Pubblicità Immobiliare, with over 45 million mechanized notes and 40 million notes in digital format, for the owners identification of the actual property rights; Sistema Informativo dell Osservatorio del Mercato Immobiliare, with over 340,000 sheets of the characteristics of the buildings of 1,280 municipalities and more than 180,000 real estate values concerning 31,000 census areas for 17 building types, in almost all Italian municipalities. Thanks to the investment of significant resources, the Agency is currently engaged in the creation of advanced and innovative methods of consultation and use of their knowledge through an infrastructure called Anagrafe Immobiliare Integrata, addressed to all the administrations, institutions, professionals and citizens dealing with the government of the territory; according to Article 19 of Legislative Decree 31 May 2010, n. 78, it is the result of the integration of the three systems described above. The Anagrafe Immobiliare Integrata is a technological and organizational infrastructure, on a geographical basis, made by Web-GIS technology and able to correlate the cadastral mapping, the Cadastre (census archives of land, buildings and floor plans) and the archives of the Conservatoria dei Registri Immobiliari e dell Osservatorio del Mercato Immobiliare. Through an advanced and easy-to-use geographic interface, achieved by the integration of cadastral maps with high definition orthophotos and road graphs, will allow citizens, professionals, public administrations and institutions to navigate, via the internet, throughout the nation and perform with extreme simplicity, the visura ipo-catastale, integrating the map data, the Land and Building Cadaster (objects) with those of the Conservatoria dei registri immobiliari (subjects).

Technologies and spatial data for modern land governance. Tools to support the cadastral reform 11 The cartographic heritage of the Cadaster After this general overview, now we focus the attention on the mapping system of the Cadaster which forms the basis of the real estate geo-localizing in Italy. The term geo-localizing means the capability of the cadastral information system to identify a property, throughout the country, in a simple and unambiguous way. The Agency manages, on behalf of the State, the real estate information system in Italy, in terms of identification, description of the technical characteristics and economic evaluation and registration of rights. The geo-localizing of real estates is based on the cadastral mapping system. Since 1960, the cadaster, as an official cartographic body of the State, is responsible for the management of cadastral maps and especially its continuous updating. The mapping system of the Cadaster is now completed, and relatively uniform, throughout the country; it is based on large-scale mapping and entirely managed in vector format, it is connected to the administrative and census archives through a unique identifier for the entire national territory, consisting of the number of parcel. The system is now integrated with high-resolution digital ortho imagery and road graphs, but the real strength is its updating system. The maps and census updating system The inextricable link between the technical component of the map and the legal and administrativecensus component, represented by the register identifier (parcel number), must be constantly updated and aligned in both archives throughout all stages of preservation, in order to make effective land registry information in all tax, civil and land governance proceedings. Data updating in separate files and the maintenance of their congruence over time, even in relation to the large amount of documents presented every year at the offices, has always represented to the Cadaster a challenge and a goal to be pursued at all costs. In the more general framework, for the exchange of information with other local authorities where the Cadastral database is characterized by a great potential, in order to meet the needs of territorial knowledge, punctual and prompt updating of archives by automated and standardized procedures is essential to ensure the constant updating and synchronization of information provided by the various cadastral archives. To cope with the amount of more than 600,000 updating acts presented every year at the provincial offices of the Cadaster handling an average of 1,500,000 parcels, in order to eliminate any possible subjectivity in technical examination of documents, the updating system of maps and census data of Catasto dei Terreni has been fully automated by a new computer procedure called Pregeo10: in the new system, the updating of land archives begins with the request, via the internet, of the map (estratto della mappa) and the corresponding census data by the professional; the provincial Office, after the appropriate checks in the database, transmits to the professional, usually within a day and no more than two, the requested map including all the necessary information for the preparation of the updating act; on the basis of the documentation received and the land survey carried out, the professional prepares the updating act, in Pregeo10 environment; after all the formal and substantial check, the procedure, determines directly at the professional if the updating acts will be automatically registered in the archives or not; the documentation prepared by a professional, is sent, via the internet, to the provincial Office in charge; a fully automatic management and control system, based on the Pregeo10 procedure, checks the correctness of the act and the congruence of the data with those previously found in the archives

12 Flavio Celestino Ferrante and Gabriele Garnero and, in case of positive exit, provides for the automatic cartographic and census updating, otherwise returns the act to the professional indicating the reasons that have prevented the registration of documents and corrective actions; the process ends with the automatic transmission to the professional of the updated map and census data. Figure 1 Diagram of the automatic update process with the Pregeo10 procedure The new updating system, developed by the Agency with the active participation of concerned National Boards of Professional Associations, is entered into force throughout the country on October 15, 2009. By achieving this important goal, the Cadaster has marked another important milestone of efficiency and administrative culture. The new updating system, based on the sharing of rules and data on the web, qualifies the Cadaster as Public Administration type 2.0. The coordinate system of cadastral maps and its interoperability with other data of land knowledge During the 70 years of its formation, from 1886 to 1956 (Kraus, 1994), the Italian Cadaster for the classification of its cartography had the need to create more than 800 different coordinate systems which have been, until recently, a major obstacle to real estate geo-referencing and interoperability and the automatic integration of cadastral system with other data bases of land knowledge such as ortho-images, technical maps, Territorial Data Bases, planning instruments, road graphs, etc..

Technologies and spatial data for modern land governance. Tools to support the cadastral reform 13 Figure 2 Cadastral coordinate systems in Italy In order to unify the coordinate systems and to transform cadastral maps in the national Roma1940 system, a scientific, organizational and technological effort has been required, which involved the Cadaster in the last 10 years, and today we can say that it is in a conclusive phase (Godone, Garnero, 2013; Ferrante, 2009; Chiabrando, Garnero, Godone, 2008). The transformation of the cartography in the national system has already been implemented on more than 80% of the national territory, with rigorous methodology, ensuring a decimeter accuracy in the coordinates conversion. At the time of the publication of this paper, the activities are still ongoing, carried out in cooperation with the University of Rome La Sapienza, Department of Hydraulics, Transport and Roads, in order to validate solutions made by the Cadaster and to guarantee the correct transition from cadastral coordinates systems to Roma1940 system.

14 Flavio Celestino Ferrante and Gabriele Garnero The transformation of the remaining 20% of the territory has been achieved only with analog methods, however ensuring a metric accuracy; the activities are currently on progress for the transformation of this part of the residual maps, with rigorous methods, and are scheduled for completion by the end of 2013. Figure 3 Coverage of the areas where parameters are available for the rigorous transition from cadastral system to the national system As required by the INSPIRE Directive, all European countries should share their geographical data in a unified reference system; with the DPCM of November 10, 2011 the new National Geodetic System was officially adopted in Italy, carried out by the ETRF2000 (at the epoch 2008.0) of the European Reference System ETRS89. In order to achieve this extra step from the national to the European geodetic system, the Cadaster has partnered with the Istituto Geografico Militare, which has developed the transformation grids allowing the direct transformation from the national to the ETRF2000 system. By the end of this year (2012), the cadastral mapping system can be re-projected by the user into

Technologies and spatial data for modern land governance. Tools to support the cadastral reform 15 the WGS84 system, within the ETRF2000 reference frame. It is hardly necessary to point out that the availability of cadastral maps in the new unified reference system represents an added value for the whole cadastral information system, as it ensures full interoperability and automatic integration with other data of land knowledge, also with those outside the domain of the Cadaster. The recovery of the accuracy of the maps and the creation of topological congruence through the enhancement of original maps The original map is an invaluable asset of technical, legal and historical information; this original and unique map is still used as supporting evidence in the regulation of boundaries and, if only for this reason, it should be preserved from the injuries of time. The plan already started in 2008, provides the acquisition and geo-referencing of the cartaforte where the original map is represented. In view of its high tech features, the integration of the original maps, in digital format, into the information system of the Cadaster will improve the quality of the vector maps acquired by the most updated media, but of lower quality, and retrieve the systematic errors inevitably introduced by the process of computerization and updating; the partly automatic and interactive process initially provides for the calibration of the vector map on the original one. As described in a previous study by the same authors, the automatic creation of topological congruence is automatically recreated first within each sheet of the map and then between adjacent maps, and finally, through an interactive intervention, all the problems the automatic procedure could not define are solved. It is hardly necessary to point out how this condition is essential for achieving the mosaic (territorial continuum) and then making applicable all the potentials based on the topology which GIS technology makes available today. Recovery of the coherence of the data in maps with the Catasto dei Terreni census data The maps and the corresponding census archives are, as already mentioned, closely related and must be constantly updated and congruent, in order to fulfill all the fiscal and civil functions of a modern cadaster, especially if some complex and difficult projects, such as the reform of the cadastral appraisal system, should be carried out. Throughout the first period of preservation of the Cadaster and until the end of the 80s of the last century, the map updating was obtained separately from the corresponding census records: it was performed by cadastral technicians, on paper supports, manually registering the changes in the technical documents. This method of updating has led, over time, to a gradual but inevitable misalignment between the two archives. Currently, since the late 80s, cartographic and census archives are updated simultaneously by the Pregeo procedure previously mentioned: it thus guarantees the complete congruence of archives in the data flows which have to be updated. Therefore it is necessary to provide for the recovery of past misalignments, before starting the automatic procedures. Many changes were made in this direction, both targeted (projects for internal use, collaborations with external institutions) and put into practice in case of use (resolution of any misalignment before releasing the extracts of the map), aimed to resolving mismatches between the map and census archives of the Catasto dei Terreni and the census data of the building cadaster. As shown in the following two images, the misalignments still found are focused only on a dozen of cadastral offices. Testing activities are currently underway for the adoption of a new organizational model that will allow their resolution, without any impact on the ordinary activities of the offices.

16 Flavio Celestino Ferrante and Gabriele Garnero Figure 4 Misalignment between cartographic and census archives: parcels present in maps and not registered in the census archives of the Land Cadaster (left) and parcels present in the census archives of the Land Cadaster and not represented in the map (right) Recovery of the coherence between the data in the maps and the census data of the Catasto dei Fabbricati The Catasto dei Fabbricati (building cadaster), as known, was established in the late 30s of the last century, and has been, for some regions, based on urban maps completely detached from the map of the Catasto dei Terreni (land cadaster): this condition has generated over time a number of mismatches between the map and census data of the Catasto dei Terreni and the census data of the building cadaster. Aware of the need of aligning the two registers, from more than a decade, the AdT is engaged, with extensive qualified internal resources, in achieving the correlation between the cartographic and census maps of the Catasto dei Terreni with those of the Catasto dei Fabbricati; currently the activities are still in progress. The consistency of the data in the archives, introduces the map geo-referencing of the housing units in the archive of Catasto dei Fabbricati. This creates the conditions that enable the full exploitation of the potentials of modern GIS systems. It is hardly necessary to point out how the effectiveness of the analysis and, consequently, of the solutions, depend strongly on the degree of correlation between the archives.

Technologies and spatial data for modern land governance. Tools to support the cadastral reform 17 TECHNOLOGIES AND DATA OUTSIDE THE DOMAIN OF THE AGENZIA DEL TERRITORIO The ortho imagery produced by Agea and identification of unknown buildings in the Cadaster In the context of spatial information available throughout the Country, the ortho images produced by Agea (Agenzia per le Erogazioni in Agricoltura) certainly occupy an important position in the context of the checks provided by the Community regulations for the management of the contributions granted under the CAP (Common Agricultural Policy). Agea is responsible, according to Decree 99/2004, of the coordination and management of the SIAN - National Agricultural Information System where a full aero-photogrammetric coverage is provided every three years throughout the entire national territory and the production of the cultivation themes based on cadastral maps, in regard of agricultural land. The Decree 82/2005 (Digital Administration Code) establishes the principle of the reuse of the data generated by each Public Administration and their accessibility, through appropriate agreements, by other administrations concerned. From 2010, in order to optimize its aspects related to the reuse of ortho images, the planning of survey programs has changed, which now become on a regional basis rather than provincial, and opens the possibility for the concerned administrations, to acquire jointly to Agea ortho imagery with the ground pixel resolution 20 cm instead of 50 cm institutionally provided: this increase in resolution, in case it would be implemented, will start from the next three years 2013-2015 and will lead to a real improvement in the possibilities of using the ortho maps produced within the SIAN for real estate updating. The ortho images with ground pixel resolution of 20 cm would allow to determine with greater accuracy the positional and close range parameters properties and, consequently, to refine the appraisal of urban housing units, considerably limiting the direct intervention on the ground. In the broader context of the fight against tax evasion, the AdT has undertaken a long series of actions aimed to identify potential evasion in real estate projects with high technological contents. In the recent past, according to the provisions of the Finance Act of 2007, as it is known, the AdT has undertaken a significant project to identify the buildings unknown by the Cadaster. The project, characterized by an advanced technology, was prepared in collaboration with AdT, Agea and Sogei (Società Generale di Informatica) and is one of the most significant examples of cooperation and integration between information systems of Public Administrations. Thanks to a special agreement signed in May 2007, the agencies have identified the common ground where their skills might find useful synergies for the government and citizens, in the general interest of the State. In order to achieve this goal, a general survey of the whole country has been carried out, with the exception of the Autonomous Provinces of Trento and Bolzano. The local survey was carried out through the integration of cadastral maps in vector format with digital high-definition color ortho images, the Digital Terrain Model (DTM), the Digital Surface Model (DSM) and near-infrared images. The first step, carried out on the basis of the DTM and DSM, has involved the automatic identification of existing land features; these were then classified, first in relation to the height and then with the aid of near infrared images: it was possible to discriminate the vegetation from other artifacts, thus identifying buildings in automatic mode. The spatial intersection between polygons related to objects on the ground identified and the polygons of the buildings present in the cadastral maps allowed to highlight the parcels on which buildings were found which are not present in the cadastral maps. The results obtained were then subjected to systematic quality control, performed through the conventional photo-interpretation on the same digital high resolution ortho photos (pixels 50 cm), in order to eliminate errors that an automated process at industrial level inevitably entails, especially in relation of the quality of the used data.

18 Flavio Celestino Ferrante and Gabriele Garnero The final product of the activity, carried out in synergy with Agea, consists of a list of the parcels on which buildings were found which are not present in the maps of the Cadaster; the list of the parcels was then intersected with the data of the various cadastral archives. This operation has eliminated, from the initial parcels, the ones known in the Catasto dei Terreni, as in other internal records. The project, which began in mid-2007, was concluded in the early 2010 and has identified over 2,000,000 parcels on which there are unknown buildings. Among the positive effects of this project, the full availability for the Cadaster, of the high-definition ortho images immediately integrated with the cadastral maps in their systems must be highlighted, for the development of important projects, not least for the reform of the Cadaster. According to the current provisions of law (Decree Law 78/2010, Art. 19, Paragraph 12), from 1th January 2011, the AdT, on the basis of new information related to technical and administrative checks, remote sensing and ground surveys must provide to start the constant monitoring of the territory by identifying, in collaboration with municipalities, other buildings not declared in the Catasto dei Terreni. In order to achieve these statutory provisions and to make a more effective investigation, the AdT is considering the possibility of making use of advanced technological solutions such as aerial images acquired by oblique sensors, as explained in the following paragraphs. Figure 5 Oblique sensors integrated into the process of photogrammetric surveys

Technologies and spatial data for modern land governance. Tools to support the cadastral reform 19 Applications relating to the use of Google Earth and Microsoft Virtual Earth The diffusion of shared web tools providing completely free of charge repertoires of dynamic aerial and satellite imagery on a global scale is now well established: the basics of Google Earth and Microsoft Virtual Earth we all quickly learned to know and use for no professional applications are becoming real integrated tools proposed as a repository of spatial information not limited to data entered in network by the managers of the system, but as instruments in which it is possible to integrate and share information in different ways (Ferrante, 2010; Garnero, Ferrante, 2009). Recently, this potential has been extended to the world of geographic information systems, with the opportunity to integrate local databases with remote databases of images: the instrument is of great interest for the study of territorial and landscape issues, given the integration of GIS tools already widely used in the field, and good image quality and potentially continuously updated, allowing a careful reading of the territory and its modifications. Its implementation in the GIS also allows an active participation in the process of spatial analysis, with the option to extract data interpreted from the images in vector and/or alphanumeric geographic database. There have already been numerous studies on the possibilities of use of these innovative supports in the processes of territorial and landscape analysis, in order to identify the scale threshold beyond which the basics in subject no longer constitute a support geometrically reliable. Virtual Earth and Google Earth using a reference system that, at least in Italy, is not employed in other applications: the system 3785 - Web Mercator WGS84, as codified in EPSG Geodetic Parameter Dataset. L EPSG ( European Petroleum Survey Group ), an agency currently included in OGP Surveying and Positioning Committee, body of the International Association of Oil & Gas Producers (OGP) which provides to maintain and to issue a worldwide database of cartographic and geodetic reference systems and their transformation parameters. For the purpose of this paper, the geo-referenced images of Google Street View implemented within Google Maps and Google Earth are particularly useful providing panoramic views of 360 horizontally and 290 vertically along the streets (at a minimum distance of 10-20 meters apart) and allows users to view portions of cities around the world at ground level. Figure 6 Google Street View Car in acquisition (Source Wikipedia)

20 Flavio Celestino Ferrante and Gabriele Garnero Introduced in May 2007, the service Street View is active in Italy from October 2008; especially in 2009, there has been a rapid increase of the streets served: the cover is shown dragging an orange man (Pegman, present in task bar) and placing him in a point on the road, in order to activate the corresponding panoramic photography. To carry out the photos, Google Street View uses special cameras (the Dodeca 2360, equipped with 11 objectives and produced by the Canadian company Immersive Media ) located on the roof of cars. Pedestrian areas, parks and roads, bicycles are used instead of the specially equipped vehicle: the service is now extended to most of the main roads and urban streets of many large and small urban centers, with a coverage extended to all Italian regions, the coverage of the updated service is available online at http://www.google.com/help/maps/streetview/learn/where-is-street-view.html. It is clear that the ability to view, if nothing else, the street fronts of the areas already served by the service, can be of immediate and quick use in order to allow users a first visual access to the extrinsic characteristics of the buildings and surrounding areas. Oblique photogrammetry On the national market several companies are operating, able to realize, in addition to traditional nadir ones, photogrammetric surveys performed with sets of cameras arranged so as to capture the territory features with oblique angles, so as to give priority to the acquisition of the facades of buildings. The industrial solutions going under the name of Pictometry, Midas of Track air, ione of Visual lntelligence,...,involve the use of survey systems consisting of several cameras rigidly connected to each other, mounted on a single support on which the inertial sensor is applied (IMU) for the acquisition of the angular components of the image. In Pictometry and Midas systems there are 5 cameras, 4 of them are installed with an inclination of 40-45 from the vertical, according to the four directions of view and perpendicular to each other (forward, backward, left and right); the fifth camera is installed as the traditional photogrammetric cameras in order to capture the territory flown over from the zenith. Frames are triggered simultaneously and are therefore five images that share the same instant. The tools available allow, as well as to manage the large mass of data in navigation environments from the base ortho image, to make queries and quantitative measurements on the plano-altimetric size of buildings, thus providing the operators with performing tools for the analysis and check of buildings. As known to the authors, aerial oblique images are currently available, throughout the national territory, of all the provincial capitals and major towns with a population of over 50,000 inhabitants, with photos from 2005. Furthermore, during 2010 and 2011, the Autonomous Region of Sardinia has arranged for services relating to the contract for the Attività di riprese fotografiche a bassa quota negli agglomerati urbani della Sardegna e relativi contesti architettonici, referred to centri di antica e prima formazione o centri matrice, as defined in the art. 51 of Norme di Attuazione del Piano Paesaggistico Regionale. All urban centers have been acquired, with technology Pictometry and with ground pixel resolution of the order of magnitude of 5 cm, so as to document the landscape context in which centri matrice are located and to highlight morphological and settlement differences between centers, with particular reference to the morphology of the plains, hills, mountains, coasts, slopes, etc... The set of nadir and oblique photos allow to better understand the way in which these centers have developed, and to pick up the different building types through the analysis of the fronts of buildings and the internal parts, as well as to highlight the issues concerning the restoration and renovation of fine buildings, with a purpose of monitoring the territory, from the urban point of view in relation to

Technologies and spatial data for modern land governance. Tools to support the cadastral reform 21 the city center and the surrounding buildings. The high definition allows to document the current state of the buildings and road plots, so as to permit the establishment of a photographic support to institutional planning and regulation of the land (Cina, Ferrante, Piras, Porporato, 2012). Figure 7 Consultation of oblique images of a center of the Sardinia Region From the above, it therefore appears that the availability of already realized oblique images, relatively recent and, as previously described, directly relatable with cadastral maps with the technology to be described later, is not negligible, as it is likely to cover not less than 70% of built areas, so it is reasonable to hypothesize the development of this asset of information for the previously explained purposes, reasonably quickly, so as to avoid the natural obsolescence of the same. Among the technologies readily available, the system BLOM-urbex allows you to integrate the cadastral maps with orthophotos, displayed in the center of the screen, while the side shows the oblique images related to the same area. But it is still difficult, especially in city centers and in particular in those with complex morphology, to univocally identify the selected perspective views of the building on the cadastral map of which we want to know the characteristics. This ambiguity is resolved with the technology that will be discussed later, on the occasion of the description of 3D models of buildings. Many have also considered the possibility of integrating photogrammetric surveys performed by Agea, already mentioned above, with at least 2 oblique cameras, in order to obtain, at the same time the acquisition of frames for ortho images and oblique images to be used for applications in the built environment. Such surveys, if systematically realized, cannot of course be compared to the ones especially produced as oblique, because of the obvious shortcomings relative to the scale and therefore the size of the pixels, of insufficient capture directions and consequent deficiencies of information, with directions of building profiles completely excluded from the acquisition. Anyway it is correct to consider that such possibilities, which should be produced with very low costs because of the simultaneity with the primary observations, could be profitably used in contexts outside the city, where there are less issues of mutual coverage between buildings and where it is

22 Flavio Celestino Ferrante and Gabriele Garnero not and, it cannot be economically feasible an oblique survey in canonical way. In the economic context characterizing the present time, however is natural to consider the exploitation of what is available and usable with what can be achieved with sustainable costs, so as to ensure the economic feasibility to what is necessary to achieve the objectives. Surveys with UAV The only identification and documentation of the extrinsic characteristics of buildings could be obtained also with instruments of decidedly lower performance and less expensive than those described above as, for the applications in question, a metric quality is not required in order to perform measurements and quantitative estimates, but rather a good photographic quality that allows the operator to identify photographically all or most of the features to be detected in an inspection in the countryside, or at least to limit the visits to the controversial cases. There is thus an increasing interest in the possibility of using pseudo-amateur photographic equipment on board of unmanned aircraft, technically defined drones or UAV (Unmanned Aerial Vehicle), this means aircraft with varying size from ones for military applications to small toy model aircraft. The availability of GNSS positioning systems sufficiently precise can be obtained with very small size and weight (generally U-Blox), together with the existence of microscopic accelerometers and gyro sensors with MEMS technology, with software controlled now generally available in open source, opens new possibility of realization of systems for the acquisition of digital images on board of aircraft of various sizes. The recent regulations issued by ENAC ( National Agency for Civil Aviation ) NI-008-2012, dated August 2, 2012 on the Rilascio di permesso di volo per Aeromobile a Pilotaggio Remoto per l effettuazione di attività sperimentale defines precisely the activities of so-called mini - and micro-uavs (respectively weighing less than 20 and 5 kg) and at up to a limit of 150 kg in respect of activities which, though still described as experimental, can obviously have interesting professional consequences. In the near future, it will also be possible to perform low altitude surveys, with tools like APR (Aircraft in Remote Steering), to recover photogrammetric information that would not be acquired through inspection, both for lack of access and for economic reasons. Technology for the virtual reconstruction of built areas The availability of information already acquired and also the possibility that other acquisition channels are activated, for large parts of the territory as for decidedly sub-regional context, allows to define a profitable use of these observation methods within the cadastral issues, even in relation to the availability of technologies that can be easily customized for these specific needs. An operator setting himself the aim of verifying the extrinsic characteristics of buildings using aerial oblique images, should be able to operate in a dedicated software, which allows him to see the cadastral map integrated with the ortho image, and should be able to see oblique images with the help of software minimizing the possibility of misidentification of the building while synchronizing the oblique view on the building pointed on the map. To this aim, in addition to the customization of the environments of consultation of the oblique images which we have been previously shown, the implementation is now feasible, albeit in a simplified mode, of a 3D City Model dedicated to cadastral applications. This term is technically defined as a consultation environment in which the buildings are reconstructed geometrically as solid and whose faces are draped from the information available on the radiometric frames: in this way the user forgets the frames and finds a virtual model reconstructed on which he can perform the observations or possibly measurements.

Technologies and spatial data for modern land governance. Tools to support the cadastral reform 23 The construction of the 3D City Model has long been present within the geomatic products available on the market, but only the recent improvements in the techniques of autocorrelation allow to plan of generation processes achievable in entirely automatic mode, with consequent reduction of costs of production and therefore openings to more generalized use. Figura 8 Prototypal realization of a 3D City Model using an oblique Midas (property Blom CGR) survey with Menci Software, technology on the city of Milan Of course, once available, the performed basic may be exploited and also used for different purposes, for example for the integrated protection and control, in municipal databases. INTEGRATION OF GIS TECHNOLOGY AND DATA INSIDE AND OUTSIDE THE DOMAIN OF ADT As shown in the Introduction, it appears how for the implementation of plans of cadastral surveys reforming, geographic data (cadastral maps, orthoimagery, LiDAR data, oblique images captured by sensors, road graphs, Osservatorio del Mercato Immobiliare zoning,...) and alphanumeric (DB censuario, terreni ed urbano, DB of OMI, of Conservatorie dei Registri Immobiliari, ) knowledge of the real estate Italian are strategic. The effective exploitation of all these information components in a suitable environment that can integrate and correlate data from different sources, is essential for the success of the project of reforming the estimate of the Catasto dei Fabbricati. The environment able to integrate geographical and alphanumeric data along with the technologies, as known, is the GIS (Geographic Information System). For issues related to the reform of the cadaster, GIS platforms allow for example to correlate data of the Urban Building Units (UIU) directly to the cadastral map: the operator can perform precise analyzes or statistics of any attribute of UIU (value/rent, classification, consistency ) and represent reports on cadastral maps which, when suitably integrated with the high resolution orthophotos, allows to correlate the data position and/or overlooking with classification or consistency of the data of UIU.

24 Flavio Celestino Ferrante and Gabriele Garnero The figure below shows, for example, on the cadastral map integrated with the orthophotos, reports of a statistical analysis conducted on the data of classification of the Urban Building Units of a central area of Rome, a comparison between the statistical data of classification of building units both those within the same building and those in the same area of study, highlighting some of the inequalities in classification that the cadastral survey review should cancel or at least reduce. Figura 9 Cadastral maps integrated with orthophoto maps and graphs. Results of the analysis on spatial data "classification" of Unità Immobiliari Urbane (pie charts and their legend) It is thus possible to integrate and analyze, on the same GIS platform, data relating to the characteristics of the extrinsic buildings: such information can be effectively drawn from close-up images of the sensors acquired simultaneously with the nadir images and allows, as indicated, to relate the buildings fronts with "buildings polygons" represented on the cadastral map, without any ambiguity. CONCLUSIONS The position/overlooking data and those relating to the extrinsic characteristics of the building thus allow to effectively implement the estimation algorithm for the value of the building and severely limiting the direct intervention on the ground, with an obvious containment of time and costs. The assumed GIS platform is crucial in analysis and management of data, in preparation for the estimation of property values, but it becomes particularly strategic in the final phase of the process,

Technologies and spatial data for modern land governance. Tools to support the cadastral reform 25 that is, when it comes to review and harmonize values and UIU rents of neighboring buildings belonging to different areas characterized by different values of the real estate market or to different municipalities or even to different provinces or regions. References Chiabrando, R., Garnero, G., Godone, D. (2008), Basi dati condivise per l analisi e la progettazione territoriale: Google Earth e Virtual Earth cambiano le prospettive sulla gestione dei dati territoriali, Congresso AIIA 2008: Segni dell uomo e trasformazioni del paesaggio: analisi storica e prospettive di valorizzazione, Marina di Pisticci (MT), settembre 2008. Cina, A., Ferrante, F., Piras, M., Porporato., C. (2012), La trasformazione dal Datum Catastale al Datum Roma 1940 e ETRF2000, Territorio Italia, n. 1/2012. Di Filippo, S., Ferrante, F., Garnero, G., Gnesivo, P. R., Rao, S. (2005), Unificazione dei sistemi d asse catastali di piccola estensione, Atti del Convegno Nazionale SIFET 2005, Palermo-Mondello, giugno-luglio 2005. Ferrante, F. (2010), Il sistema di aggiornamento della cartografia catastale, Un tesoro Ritrovato, Cangemi Editore 2010. Ferrante, F. (2009), Il nuovo sistema di aggiornamento del Catasto dei Terreni, Rivista dell Agenzia del Territorio, n. 2/2009. Ferrante, F. (2009), L integrazione del catasto con Google Earth, Google Maps e Street-View, Territorio Informa, gennaio/marzo 2009. Garnero, G., Cogoni, A. (2012), Activity at low altitude photography in urban agglomerations of Sardinia and its architectural context, in Planning Support Tools: Policy Analysis, Implementation and Evaluation. Proceedings of the Seventh International Conference on Informatics and Urban and Regional Planning INPUT 2012, E-book ISBN code: 9788856875973, Franco Angeli, Milano, 2012. Garnero, G., Ferrante, F. (2009), La valorizzazione delle mappe originali di impianto del catasto per la ricostruzione delle congruenze topologiche tra fogli adiacenti, Atti della XIII Conferenza Nazionale ASITA, Bari, dicembre 2009. Godone, D., Garnero G. (2013), The role of morphom etric parameters in Digital Terrain Models interpolation accuracy: a case study, European Journal of Remote Sensing, n. 46/2013 (doi: 10.5721/EuJRS20134611). Kraus, K. (1994), Fotogrammetria (trad. italiana di S. Dequal), Ed. Levrotto e Bella, Torino, 1994. Paroli, A. (1958), Metodi e strumenti di Rilevamento nei 70 anni di formazione del Catasto Terreni, Rivista del Catasto e dei Servizi Tecnici Erariali, Nuova serie anno XIII n. 4/1958