Typically, metadata standards involve categories 
like 
° Dataset Identification 
° Dataset Overview 
. Dataset Quality Parameters 
. Spatial Reference System 
. Geographic and Temporal Extent 
. Data Definition 
. Classification 
. Administrative Metadata 
. Metadata Reference 
There is very little theory on metadata - and even 
less practice. Everybody talks about metadata, but 
who produces and who uses them? 
A recent case study in Austria applied the proposed 
CEN metadata standard to eleven digital spatial 
data sources [Timpf et al. in press]. It found that 
the standard is comprehensible and applicable. 
Producing metadata was feasible for practitioners 
and the results understandable to them. The major 
issues were, however, whether the metadata 
themselves are usable and relevant to potential 
users. Do they provide answers to the questions of 
a potential user who needs to decide if a dataset 
should be acquired for a specific task? 
Current thinking about metadata emphasises 
completeness instead of usability. It promotes a 
tendency for data cataloguing, leading to 
voluminous and difficult to use metadata collections 
in turn. At the end of the case study, there was a 
general feeling among the metadata producers that 
potential data users would still be confused, but on 
a higher level. There seems to be a complete lack 
of considerations for the use and the user of 
metadata. 
lll. FUTURE DEVELOPMENTS 
If metadata are not yet the answer to the usability 
problems that slow down the development of data 
markets, where should we look for future 
answers? 
The general recognition of some facts about data 
and information products provides some guidelines. 
Firstly, it has become obvious that nobody wants 
to buy data as an end in itself. Rather, customers 
want information, providing answers to specific 
questions, which are important to them. Secondly, 
information system research has found that the 
traditional emphasis on data, neglecting operations, 
is detrimental to the usability of the data. The 
62 
separation of data from the operations that they 
support induces a loss of semantics [Kuhn 1994]. 
Thirdly, current metadata activities show that 
data do not become usable through documentation 
alone. 
These observations suggest a new approach to the 
production of usable spatial information: To define 
and standardise interfaces for spatial information 
services, rather than interfaces for data exchange. 
Following the paradigm of object-orientation and 
targeting modern client-server architectures of 
GIS, data and operations are recognised as 
belonging together .and forming packages that 
provide services to users. These service 
interfaces act as contracts between the suppliers 
and consumers of spatial information. Instead of 
trying to transfer spatial data among monolithic 
GIS, modular GIS functionality then becomes 
distributed over a global network. This idea is 
currently being developed and implemented by the 
Open GIS Consortium [Buehler and McKee 1996]. It 
is based on the philosophy of Occam's razor: 
simplifying as much as possible (but not more). A 
simpler interface reduces the documentation 
needed to explain complexity. 
References 
Buehler, K. and L. McKee, ed. OpenGIS Guide: An 
Introduction to Interoperable Geoprocessing, Part 1 
of the Open Geodata Interoperability Specification 
(OGIS). The Open GIS Consortium, Inc. (OGC), 35 
Main Street, Suite 5, Wayland, MA 01778. 
Available from http://ogis.org/, 1996. 
CEN. Geographic Information - Data description: 
Metadata. CEN TC287, 1995. Draft Standard. 
Kuhn, W. “Defining Semantics for Spatial Data 
Transfers.” Proceedings 6th International 
Symposium on Spatial Data Handling, 1994. 
Timpf, S., M. Raubal, and W. Kuhn. “Experiences 
with Metadata.” In Proceedings 7th International 
Symposium on Spatial Data Handling, in press. 
Address of Authors 
Doz. Dr. Werner Kuhn 
Prof. Dr. Andrew U. Frank 
Dept. of Geoinformation, Technical University Vienna, 
Gusshausstrasse 27-29/127, A-1040 Wien, Telephone: 
(++43 1) 58801 3787, Fax: (++431) 504 3535, email: 
kuhn @ geoinfo.tuwien.ac.at 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B6. Vienna 1996 
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