Common Implementation Strategy for the Water Framework Directive

WFD CIS Guidance Document No.9
Implementing the Geographical Information Systems (GIS) of the Water Framework Directive
Some of the ideas/proposals presented in this Section are drawn from documents produced by
European projects like ETeMII [2] and Madame [3], from software manuals [4] and from the
collaboration between JRC, Eurostat GISCO and the EEA.
3.8 Standards for Data Exchange and Access
The way data is collected and stored, its quality and coverage will vary from organisation to
organisation. In order to reduce the likelihood of data being unusable by the Commission,
common exchange formats need to be agreed. This also speeds up the quality assurance issue
and makes the data readily available to other Member States. It is not sensible to nominate
any one proprietary format as this may limit the software options of the Member States.
There is also the need to explore the options available to allow the enhancement of data
delivery in the future. The priority however is the reporting needs in the short term. In this
document short term refers to the delivery of data to the Commission in 2004. The longerterm
goals are targeted at data delivery in 2009.
3.8.1 Short-Term Data Exchange and Minimum Long-Term Requirements
The best practice will be data exchange using Geography Markup Language (GML). GML is
an XML encoding for the transport and storage of geographic information, including both the
geometry and properties of geographic features. Many of the current commercial GIS
packages offer the facility to import data in a GML format. The current versions of most
GIS’s do not offer the ability to directly export in GML. There are however, several data
translators on the market which provide this functionality (an example is “Feature
Manipulation Engine”, more information at www.safe.com).
Using GML removes many of the problems caused by file conversion by some commercial
and non-commercial GIS programmes. This also supports the long-term goal of using
OpenGIS or other web based technologies for data transfer. The current version is GML
Version 2.1.1. Later versions (as and when they become available) may be used. However
the default will be 2.1.1. For further information see http://www.opengis.net/gml/02-
009/GML2-11.html.
Conforming to the OGC Simple Features model, GML provides geometry elements
corresponding to the following Geometry Classes:
�� Point;
�� LineString;
�� LinearRing;
�� Polygon;
�� MultiPoint;
�� MultiLineString;
�� MultiPolygon;
�� GeometryCollection.
59