Methodology of transformation the environmental geospatial data to the INSPIRE schemas (The case of hydrogeology)

Abstract

At present, teams of experts are carrying out works on development of the Polish part of the European geospatial information infrastructure under the INSPIRE initiative. One of the key and very difficult tasks is to create datasets that meet the requirements of INSPIRE documents as a result of transformation of national data sets from their present form. This problem applies to all domain-specific themes listed in the Annexes of the Directive, including hydrogeological data.
This monograph presents the results of works performed within the framework of a research project which aim was to develop technology and methodology of the national hydrogeological data transformation to the form and structure specified in INSPIRE guideline documents related to this theme. The basis for this transformation is the technological concept referred to as the ETL: Extract – Transform – Load, which basically boils down to a process consisting of three phases: 1 – download the data from the source and save it in a tagged form (XML), 2 – convert it to a given new content and forms (including XML) using an XSLT processor (Extensible Stylesheet Language Transformations), 3 – put the results in a repository or a database.
Assumed methodological and technological solutions are not limited to hydrogeological data, being the main subject of analysis and testing. The results can - without significant modifications - be applied to geospatial data from other fields, particularly in the scope of disciplines related with the natural environment.
Problems presented in this monograph concern a number of aspects; the most important of them include:
• The present state of national hydrogeological data – their content, structure, forms of encoding, the way of storage and the rules of sharing.
• The requirements of the INSPIRE documents, including legal acts, thematic and technical specifications, as well as the adopted organizational rules in the infrastructure.
• Accepted international standards for geoinformation, geospatial systems, their interoperability with particular emphasis on data models, which are directly applicable to the hydrogeology.
• The standard technological solutions for data processing in the tagged encoding (XML), and particularly the use of XPointer, XPath, XLink, and XQuery languages because they are directly related to the XSLT technology.
• The methodology and its tools for storing and retrieving data in the form of tagged encoding, and databases dedicated to this form of data storage.
• Specialized tool systems, both commercial and Open Source, designed to transformation of geospatial data.
• Software tools for supporting transformation processes, such as XML editors and GML data viewers.
Analytical and test works performed in the frame of this project have shown that transformation of presented hydrogeological data is fully feasible, but not all the detailed operations can be automatically performed at this stage without manual intervention. Therefore, the need for further research exists, that would fully automate the process of transformation and direct human intervention would be required only to determine the tasks for batch processing and to check the results.