MAINTENANCE EN COURS / SITE UNDER MAINTENANCE

Une opération de maintenance est en cours: les résultats de recherches et les exportations peuvent être incohérent.
Site under maintenance: search & exportation results could be inconsistent.
 

Homogenization of data : issues and methods in soil geochemical mapping

Pereira, Benoît
(2016)

Files

These_pereira_16_24_complet.pdf
  • Open Access
  • Adobe PDF
  • 27.91 MB
Download

Details

Authors
  • Pereira, Benoîtorcid-logoUCLouvain
    author
Supervisors
Sonnet, Philippe
Abstract
Geochemical mapping projects carried out in the last fifty years both in Europe and around the world have successfully met a range of needs from mineral exploration to environmental management. New databases have been created for each of these projects, representing an equal number of additional geochemical data sources. Combining data from several existing databases can be highly profitable for obtaining geochemical maps that offer greater precision and/or that cover larger areas. However, the data quality of the datasets can be highly variable and, in many instances, the biases between the geochemical data must be removed in order to optimally combine the different sources of data. The present thesis examines these issues by taking into account the characteristics specific to geochemical data, and by defining the relevant concepts, such as the link between a geochemical value and its position in space or the notion of geochemical data equivalence. This study resulted in the formulation of a general method defining a specific set of procedures that make it possible to effectively combine multiple data sources. This general method first consists in performing four data quality checks: georeferencing, temporal variability, spatial structure and presence of censored values. It then includes two procedures, each having a specific scope, which serve to detect the biases between data and to correct them through linear transformation. The feasibility and the advantages of the proposed procedures are demonstrated using several case studies focusing on soil geochemical mapping both in Wallonia (Belgium) and in Europe. The scope, benefits and limitations of the proposed procedures are discussed, and the performance of the bias detection and the correction procedures are evaluated using Monte Carlo simulations.
Affiliations
  • Institution iconUCLouvainSST/ELI/ELIE - Environmental Sciences

Citations

  • APA
  • Chicago
  • FWB

Pereira, B. (2016). Homogenization of data : issues and methods in soil geochemical mapping. https://hdl.handle.net/2078.5/179770