Issues of compatibility of geological data resulting from the merging of many different data sources and time periods may jeopardize harmonization of data products. Important progress has been made due to increasing data standardization, e.g., at a European scale through the SeaDataNet and Geo-Seas data management infrastructures. Common geological data standards are unambiguously defined, avoiding semantic overlap in geological data and associated metadata. Quality flagging is also applied increasingly, though ways in further propagating this information in data products is still at its infancy. For the Belgian and southern Netherlands part of the North Sea, databases are now rigorously re-analyzed in view of quantifying quality flags in terms of uncertainty to be propagated through a 3D voxel model of the subsurface (https://odnature.naturalsciences.be/tiles/). An approach is worked out to consistently account for differences in positioning, sampling gear, analysis procedures and vintage. The flag scaling is used in the interpolation process of geological data, but will also be used when visualizing the suitability of geological resources in a decision support system. Expert knowledge is systematically revisited as to avoid totally inappropriate use of the flag scaling process. The quality flagging is also important when communicating results to end-users. Therefore, an open data policy in combination with several processing tools will be at the heart of a new Belgian geological data portal as a platform for knowledge building (KB) and knowledge management (KM) serving the marine geoscience, the policy community and the public at large.
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RBINS Staff Publications 2017
To ensure harmonised seabed mapping over large areas and to facilitate the exchange of information, a common geological knowledge base is being developed for the southern part of the North Sea. Data, sustaining this marine geological database, originate from a variety of sources, including the industry. Related to the seabed and its subsurface, two main databases are being compiled: one comprising all available lithological descriptions and one with all numerical grain-size information. To enable standardisation of the data and make them easily queryable, non-numerical descriptions are being coded to an international standard (EU FP7 Geo-Seas), of which the Udden-Wentworth scale is the main classifier. Several other parameters were derived, such as percentages mud, sand, gravel, shells and organic material. For the second database, cumulative grain-size distribution curves were compiled, enabling calculations of any desired granulometry parameter, such as percentages of the grain-size fractions (fine, medium, coarse sand) and percentiles that are relevant in seabed-habitat mapping or sediment-transport modelling (D35, D50, D84). To quantify data uncertainty in the derived data products, metadata on sampling and coring techniques, analytical methods, horizontal and vertical positioning accuracy and the exact timing of data acquisition were included. These metadata fields are also crucial in the quantification of habitat changes, a key issue in the assessment of good environmental status within Europe’s Marine Strategy Framework Directive. The newly developed database and its associated data products contribute to the objectives of the projects TILES (Belspo Brain-be), EMODnet-Geology (EU DG MARE), and ZAGRI (private revenues from the marine-aggregate industry).
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Within the framework of marine resource management, a common knowledge base is being developed on the distribution, composition and dynamics of various geological resources. Focus is on data from the Belgian part of the North Sea, being representative of a typical sandbank sedimentary system. To ensure harmonised seabed mapping over large, supraregional areas and to facilitate the exchange of information, special attention was paid to compatibility with marine geodatabases from the adjacent Netherlands territory. With reference to the seabed and its subsurface, two main databases are being compiled: one comprising all available lithological descriptions and one with all numerical grain-size information. To enable standardisation of the data and make them easily query-able, non-numerical descriptions are being coded to an international standard (EU FP7 Geo-Seas; www.geoseas.eu), of which the Udden-Wentworth scale is the main classifier. Several other parameters were derived, such as percentages mud, sand, gravel, shells and organic material. For the sediment database, cumulative grain-size-distribution curves were compiled, enabling calculations of any desired granulometry parameter, such as percentages of the grain-size fractions (fine, medium, coarse sand) and percentiles that are relevant in seabed-habitat mapping or sediment-transport modelling (D35, D50, D84). For both databases, the completeness and accuracy of the metadata were considered highly important. Information about sampling and coring techniques, analytical methods, horizontal and vertical positioning accuracy, and the exact timing of data acquisition is pivotal in uncertainty analyses, which are an increasingly important element of seabed mapping. The time of seabed mapping is critical to convert measured water depths to a common datum such as TAW in Belgium, facilitating integration of sample data in bathymetry data and thus their incorporation in 4D-modelling studies on morphodynamic change. For Belgium, the geological databases will be imbedded in the data infrastructure of the Belgian Marine Data Centre (www.bmdc.be), ensuring compatibility with international standards and providing easy access to a wide user community. Following processing to generate data products such as resource-related subsurface models, visualisation is foreseen through Subsurface Viewer (GmbH INSIGHT). Applied maps and models thus disseminated are crucial in decision making, and invaluable for outreach and educational purposes. The newly developed database and its associated data products will contribute to the objectives of the projects TILES (Belspo Brain-be), EMODnet-Geology (EU DG MARE), and ZAGRI (private revenues from the marine-aggregate industry).
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RBINS Staff Publications 2016
