Fabio Crescenzi Territorial Databases and Gis Applications of Gis and Census mapping to increase small area data availability Fabio Crescenzi Territorial Databases and Gis

Gis and small area data A better integration of Gis in statistical applications, a better integration of all available data and a more intensive use of all census outputs may produce a relevant gain in quantity and in quality of small area data. Map integration of several geo-data sources like remote sensing images, ortophotomaps, regional technical maps, National Mapping Agency's cartography, Cadastral maps, street-maps of private companies for geo-marketing, facilitate area mapping and allows to increase knowledge on small areas.

GIS – new application of spatial analysis Statistical inference and statistical modelling should be more integrated in GIS tools. Examples of future use of GIS are: models for non response evaluation and correction models for data estimation when source and target zones do not match new methods and applications of administrative records geocoding New opportunities are given by new modules of geographical and statistical packages.

Gaps for an immediate wider use of geo-data in statistics: a) lack of awareness of existing geo-data; b) lack of efficient and user-friendly data-interchange and communication procedures; c) redundancy in data acquisition and data storage; d) insufficient update of data; e) lack of guidelines for meta-information; f) price highly variable; g) problem of copyrights.

Main applications of Gis at Istat census mapping; delineation of spatial units; production of digital census atlas on CD-ROMs; geocoding of addresses on maps; display and check of functional zones (i.e.: local labour areas); pilot study on morphological urban agglomerations; data access via intranet-internet.

Delineation of spatial units Aim as possible to harmonize definitions and to integrate small areas systems. administrative units sub-urban district functional zones all small area systems used in different surveys.

Census GeoDatabase Administrative units built-up areas census sections Boundaries in ARC-INFO format. Reference system: UTM / Gauss Boaga Administrative units built-up areas census sections Sub-urban district

Fig. 1 Example of census mapping in a sampled area of Verona - NA.

Fig. 2 Example of census mapping in a sampled area of Verona - CS

Fig. 3 Sciacca (Sicilia) Orthophotomap and census mapping

Managing nomenclatures of administrative units Nomenclatures of territorial units at any time represent an essential tool to correctly refer data to territory. Changes over time is one of the most important problem to manage, and the task is even more complex considering the links of administrative units, which are hierarchically connected.

Address matching a powerful tool to increase local data production. Coordinates of address numbers are not available An address matching procedure allow to link to each address the Sdc code after the addresses orthographic correction and normalization. The main application is geocoding of businesses in ASIA (the Italian businesses register). Applications will be extended in the next years also to geocoding of records from population and social registers, including schools and hospitals registers.

Fig. 4 Example of delineation of Sdc in the CA of Mantova. .

GEOCODING OF MILAN MUSEUM

Local labour market areas One gap in local analysis is that data are usually referred to administrative areas which are virtually without geographical or statistical significance. As a consequence, they are not suited to study socio-economic phenomena, nor to formulate and to manage policies intended to encourage or to contrast these phenomena. A solution is to identify territorial entities representative of the way in which the society organises itself in the space by localising residential, productive and recreational units in relation to which economic activities and social relations develop.

Local labour market areas Travel-to-work flows allow to build spatial units having a clear statistical meaning. Italian labour market areas were built using an iterative procedure designed by New Castle university on the intra-communal travel to work flows matrix. This procedure it is not based on GIS, but GIS was used to analyse and to map and to check local labour market areas.

Fig. 5 The Italian local labour systems in 1991 (in grey the metropolitan LLS).

Challenges for the next years New application of spatial analysis Increase efforts to achieve standardisation of geographical levels, classifications, concepts, used to statistical purposes. To move toward a more integrated network of all actors implementing common reference databases, common databases structure and metadata standards. Address standardization aiming to improve related data quality. Topics include address format standards, editing standards, and the application of geocoding. Location information is essential to many key application. Location is also key to many statistical applications, and is indispensable for geographic information systems. To facilitate the integration of applications and data set into a web environment and developing prototypes for data access via intranet and internet.