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GEOSTAT : THE SERVICE FOR SPATIAL DATA IN THE SWISS FEDERAL ADMINISTRATION
Hans-Ulrich Zaugg, Valérie Borioli Sandoz, Swiss Federal Statistical Office, Berne

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The Federal Statistical Office maintains with its GIS (geographic information system) infrastructure a specialised user communications team which concentrates on data diffusion, advice and information in this field. GEOSTAT contains a federal GIS database of geocoded, spatially relevant data sets coming from various, mostly governmental, sources. Services offered to official, research, as well as private customers, include dissemination of raw, digital data in various formats, custom analyses of specific data and data combinations, presentation of data and of analysis results in the form of customised computer plots as well as generation of statistical data tables for specific, but traditionally unresolvable spatially defined and related questions. This data preparation and delivery centre meets an increasing demand and tries hard to complement, update and improve the existing data sets within its GIS. Further significant enhancements may include innovative data like satellite imagery or environmental information.

Background
With the transfer of a Swiss geographical database for regional planning purposes from the Department of Planning of the Federal Technical Institute (ETH) of Zurich in 1976, the Federal Statistical Office made the first step towards the establishment of geo-referenced statistics independent of the traditionally used administrative boundaries. Since then, the information content of this grid or raster system has been systematically expanded and enhanced and the data disseminated to an ever growing group of interested data users from various fields of research, education and administration. Increasing amounts of data, greatly widened and multiplied data needs and requests, and technological advancements in computer hard- and software and data processing methods made a complete redefinition of the project and an infrastructural refurbishment mandatory. In connection with the considerable data management tasks for the new Swiss land use statistics, the installation of GIS was extensively evaluated and finally decided upon. Based on a specific analysis of users needs, a formal concept report, as well as a survey among producers and owners of geo-referenced data within the federal administration, the Swiss Interior Ministry finally decided in 1987 to formally establish the new project GEOSTAT.

Geographic information systems?
Under the term geographic information system (GIS) we understand, according to a recently published definition by the GIS working group of the Swiss Informatics Conference1, an information system containing geographical or spatially referenced data, especially on the atmosphere, the earth's surface (vegetation, land use), the soil and the lithosphere, including its technical and administrative infrastructure as well as its economic and ecological framework. A GIS facilitates systematic data capture and storage, actualisation or updating, processing, analysis and combination of such data on the basis of a common spatial reference system. Offering these capabilities, GIS is destined to support the decision finding process in administration, jurisdiction and economy as well as many other spatially relevant planning endeavours.

Statistical data?
In Switzerland, the activities of the Federal Statistical Office and the other producers of statistical data belonging to or associated with the federal government administration are defined and legally delimited by a new federal statistical law which was passed by parliament in October 1992 and has been in effect since 1st August 1993. Its third and fourth articles describe the objectives and tasks of federal statistics and the principles for surveys and data generation. They explicitly list land use and spatial data as relevant and legitimate federal statistical information. According to the official message of the Swiss Federal Council accompanying this law, statistical data includes, among other things, information on persons, households, enterprises, but also on land parcels, buildings, apartments, hectares and spatially defined points as well as on spatially referenced administrative areas and other parameters. We can conclude from this that practically all data generally kept and analysed in GIS can be consideredto be statistical or statistically relevant dataas well.

GIS concept of the Federal Statistical Office
With the framework of the federal law on statistics in mind, it is only natural that the Federal Statistical Office has tried for many years to assemble a solid basis of geo-referenced (GIS) base data, to explore the capabilities and potential of available GIS for the management, analysis, presentation and diffusion of GIS data, and to satisfy the needs of a wide range of interested data users for such data and derived products and results. In order to reap the full benefits offered by GIS it is, with the presently available and installed technology, inevitable that the Office brings together and centrally combines a variety of relevant geo-referenced statistical data which is, however, usually generated or digitized decentrally by different organizations and institutions. A national statistical office is expected to serve as an optimal location for a general data repository attracting the collaboration of data producers by offering them technical and marketing advice and by relieving them of adminis- trative and legal overheads necessary for a professional and user-oriented dissemination of their data. This approach also offers the unique possibility to data users obtaining data combinations and the results of analyses involving several independent data sets rather than being forced to assemble each and every required piece of information from its original source and invest in the infrastructure, skill and time necessary to perform every required analysis independently.

Fig. 1. Projects and activities of the Spatial Data Section

The Spatial Data Section is one of the youngest sections of the Swiss Federal Statistical Office (Fig. 1). It had its origin with the launch of a comprehensive statistical investigation on land utilization in Switzerland, but has meanwhile extended its scope and activities beyond the single aspect of land use to encompass a multitude of data and information that are available or need to be analysed within a specific geographical or spatial context. The publication and regular updating of the official Swiss land use statistics still makes up one of the major projects of the section, while the other one is the geographic information system of GEOSTAT.

Fig. 2. Organization and data flow model of GEOSTAT

Organisation
The core of the project GEOSTAT is a GIS which aims to store spatially relevant, geocoded data from a variety of fields and from a variety of data owners at a central location in order to make them available for user-defined analyses, combinations, intersections, overlays etc. The project consists, besides project organisation and management, of two project units: the user communication group on the one side and the computers and data processing group on the other. Within the Spatial Data Section, GEOSTAT is fully integrated and collaborates closely with the Swiss land use statistics and the other projects of the Section. The user communication group takes care of the data flow to and from the GEOSTAT GIS (Fig. 2). Therefore it maintains close contacts with data owners and data users and has institutionalised an exchange of information and of experience on geographic and spatially relevant data and information systems. In 1992 the first edition of a new, comprehensive users manual describing all the data available within GEOSTAT was published 2, and GEOSTAT is engaged in various efforts to compile information registers on the available GIS installations and GIS data in Switzerland.

Objectives
The main targets and objectives of GEOSTAT have hardly changed since the formulation of the original project concept in 1987. The installation of an efficient, modern GIS and the hardware upgrades and extensions of the past years now allow GEOSTAT to prepare analyses of combined data sets efficiently and fast. They were also a prerequisite for the successful verification, conclusive analysis and finally the publication of the Arealstatistik 1979/85. The most essential tasks and objectives of GEOSTAT may be formulated as follows:

- Integration, administration and maintenance of different geocoded, spatially relevant data available with the Swiss federal administration. For this data, coverage of the entire country and a spatial resolution of 100m, a map scale of 1:25,000 is envisaged.

- Integration of geo-referenced data from any data owners willing to collaborate with the target to make them accessible for administration, research and other purposes in Switzerland and to deliver desired data combinations to an interested public.

- Processing and analysis of available data according to the specific requirements of users, as well as advice to and support of users for their own analyses and projects.

- Cooperation with researchers and interested institutions to develop and test analysis methods and processing algorithms.

- Coordination, guidance and help for data collection, digitisation and use as well as for the establishment of a local GIS infrastructure, in regard to data formats, methodological aspects and later analysis, especially for federal government institutions.

Data sets in GEOSTAT
With the most recent data acquisitions, GEOSTAT can be said to have reached a somewhat mature state and to offer a basic complement of the most essential GIS data sets in high demand. The data presently available cover the multi-purpose needs of a majority of data users and can serve most of them as sufficient input for compiling reasonably detailed and diversified base maps, upon which they can easily assemble their own, specific, specialised thematic data layers. In addition, the data allows a multitude of interesting and challenging analyses to the user communities in federal, cantonal and local administration, in research and education as well as to a large number of private consultancy companies in the fields of planning, environmental issues, agriculture, sociology etc.

The table below provides an overview over the data sets presently available with their most important characteristics which are all described in detail in GEOSTAT's comprehensive user manual which is available through the Federal Statistical Office in German and French and is periodically updated 3.

Data category, thematic	Data set	Data structure	Resolution or generalisation level
Administration, Surveying	Administrative boundaries of Switzerland (communes, districts, cantons)	Polygons	1:25,000
	Generalised administrative boundaries	Polygons	1:300,000 1:500,000 1:1,000,000
Topography	DTM, height, slope, exposition; absolute and classified	Point or grid	Hectare
Geology	Simplified geotectonic map of Switzerland	Polygons	1:200,000
Hydrology, water resources	Swiss lakes	Polygons	1:25,000
	Swiss rivers and streams	Lines	1:200,000
Land cover, land use	Swiss land use statistics 1972	Grid	Hectare
	Swiss land use statistics 1979/85, 15 or 24 aggregated categories	Point or grid	Hectare
	Thematic background layers derived from the Swiss land use statistics 1979/85, 3 levels of generalisation, 17 aggregated categories	Grid	Hectare
Population, buildings	Swiss census of population 1970 (3 variables, classified results, 750 communes, approximately 60 % of Swiss population)	Point or grid	Hectare
	Swiss census of population 1980 (54 variables, 620 communes, 50 % of Swiss population)	Point or grid	Hectare
	Swiss census of population 1990 (4,300 variables, entire country covered)	Point or grid	Hectare
Planning	Legal construction zones (residential and industrial zones; approx. 1980)	Grid	Hectare
Protected areas, inventories	Federal inventory of landscapes and natural features of national importance (BLN)	Polygons	1:25,000
	Federal inventory of bird reserves of international and national importance	Polygons	1:25,000
	Federal inventory of prohibited hunting areas	Polygons	1:25,000
	Federal inventory of upland and transitory moors of national importance	Polygons	1:25,000
	Federal inventory of river meadows of national importance	Polygons	1:25,000

Future perspectives
GEOSTAT will continue to collect, harmonise and evaluate georeferenced data and to make it as widely accessible as possible. The most difficult part in the future will be to guarantee free or reasonably priced data access to anybody. Copyright and property issues on digital data and the ever more complex juridi- cal situation for data gathering projects will further slow down or in certain cases stop our efforts to prepare data for public use. The financial pressure on government agencies and the trend to implement market rules in the state administration make it already increasingly difficult to include digital data from government sources in the GEOSTAT framework. These circumstances may force us to shift our emphasis from data supply to function rather as an information centre providing free information about what geocoded digital data is avilable, on which terms, to which price, and where. Public libraries and services like ours will have to work together and share resources in this field of common interest.

References
1. Schweizerische Informatikkonferenz, Arbeitsgruppe Geographische Informationssysteme: SIK-GIS Empfehlungen 1992. Bern, September 1992 = Conférence Suisse sur l'Informatique, Groupe de Travail 'Systèmes d'information géographique': Recommandations SIG 1992. Bâle en août 93.Back to document

2. Bundesamt für Statistik: GEOSTAT - Benützerhandbuch. Bern, 1992 = Office fédéral de la statistique: GEOSTAT - Manuel de l'utilisateur. Berne, 1993. Back to document

3. Rainer Humbel: Geographical information systems for the analysis, presentation and dissemination of statistical data - the Swiss experience. In: Statistical Journal of the United Nations ECE 11 (1994), p. 19-33, IOS Press. Back to document

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