5 by Helava,
Jean-Paul, S.
opment of an
e In: The
note Sensing,
t B6, pp. 96-
a, H. Kager,
Applications,
ne: Airphoto
OPEN SOURCE BASED SPATIAL DATA INFRASTRUCTURE - WHY AND HOW?
D. Medak, B. Pribièevié, A. Papo, I. Medved
Department of Geomatics, Faculty of Geodesy, University of Zagreb, 10000 Zagreb, Croatia — damir.medak @ geof.hr
KEY WORDS: OpenGIS, Open Source Software, Java, PostgreSQL, PostGIS
ABSTRACT:
The standards for spatial data were either vendor- or nation-specific. Recent efforts of international bodies like European Committee
for Standardization (CEN), ISO (International Organization for Standardization) and OpenGIS Consortium (OGC) paved the way to
interoperability and openness of geodata and applications which handle it. Open specification enabled open-source community —
which is the main alternative to corporative monopoly, especially but not only in developing countries — to develop their own
software industry. The key area to start with is the investment in database technology, where the academic-rooted PostgreSQL is the
cutting edge in object-relational database management systems, matching the best commercial products in both reliability and
performance. Since spatial datatypes are incorporated in PostgreSQL, it is perfect for the development of spatial databases where
high performance and security is a must. PostgreSQL is based on Linux platform, but portable to Windows as well. Talking about
operating systems, many governments are migrating to Linux these years, stipulating the educational system to advance the level of
knowledge about free software in general. Beside databases and operating systems, the third phenomenon is the programming
language Java. Thanks to its open specification, platform independence, scalability, object-orientation and inherent Internet nature,
Java is the first choice for development of external schemata for spatial data infrastructure. The goal of this paper is to expose the
ideas of open source technology to the wider audience, because that technology is going to be the basis of future networked society
of knowledge. Spatial data posed so many challenges in the past resolving of which lead to the technology push. The need to put the
spatial data into open-source arena must be recognized as soon as possible to avoid neglecting of spatial data applications again.
Finally, a complete list of tools which are necessary to build the spatial data infrastructure is enumerated with comments about its
status and future prospects. These tools are freely accessible and distributable to both developers and users interested. It is natural
that the first pilot-projects should be adopted at the universities, both for educational and practical purposes. It is, however, of the
highest importance that such pilot-projects are shown to the public in order to show that there is a viable alternative to the
proprietary, licensed software solutions. This paper reviews all efforts done in this direction and gives the check list for Croatian
academia and practice in long-term dealing with spatial data infrastructure.
1. INTRODUCTION finding and using critical geographic information. This can lead
to either the abandoning of a proposed project, or to
Geographic information is vital to make sound decisions at the unnecessary — and expensive = recapture of existing geographic
local, regional, and global levels. Crime management, business information.
development, flood mitigation, environmental restoration,
community land use assessments and disaster recovery are just a There is a clear need, at all scales, to be able to access, integrate
few examples of areas in which decision-makers are benefiting and use spatial data from disparate sources in guiding decision
from geographic information, together with the associated making. Our ability then, to make sound decisions collectively
infrastructures (i.e. Spatial Data Infrastructure or SDI) that at the local, regional, and global levels, is dependent on the
support information discovery, access, and use of this implementation of SDI that provides for compatibility across
information in the decision-making process (Nebert, 2001). jurisdictions that promotes data access and use.
However, information is an expensive resource, and for this
reason appropriate information and the resources to fully utilise The term "Spatial Data Infrastructure" (SDI) is often used to
this information may not always be readily available, ^ denote the relevant base collection of technologies, policies and
particularly in the developing world. Many national, regional, institutional arrangements that facilitate the availability of and
and international programs and projects are working to improve ^ access to spatial data. The SDI provides a basis for spatial data
access to available spatial data, promote its reuse, and ensure discovery, evaluation, and application for users and providers
that additional investment in spatial information collection and within all levels of government, the commercial sector, the non-
management results in an ever-growing, readily available and profit sector, and academia and by citizens in general.
useable pool of spatial information.
The word infrastructure is used to promote the concept of a
In regions characterized by an availability of geographic reliable, supporting environment, analogous to a road or
information, in combination with the power of Geographic ^ telecommunications network that, in this case, facilitates the
Information Systems (GIS), decision support tools, databases, access to geographically-related information using a minimum
and the World Wide Web and their associated interoperability, set of standard practices, protocols, and specifications.
the way better-resourced communities address critical issues of An SDI must be more than a single data set or database; an SDI
social, environmental, and economic importance is changing hosts geographic data and attributes, sufficient documentation
rapidly. However, even in the new era of networked computers, (metadata), a means to discover, visualize, and evaluate the data
the social habits of the past continue to prohibit users from (catalogue and Web mapping), and some method to provide
193
