Evaluation of spatial interpolators in the framework of a Geographical Information System: A case study using oceanographic data

摘要

Spatial interpolation methods are widely applied in marine studies to evaluate the spatial distribution of oceanographic parameters and inter-compare time series of maps of selected variables. A variety of such methods are nowadays available and therefore, selection of the most appropriate for a specific case study is not an easy task. Within geography and other spatially oriented disciplines, and most of the times in the framework of a Geographical Information System, several attempts have been carried out to assess the efficiency of various spatial interpolators using diverse methodologies. In this paper, an attempt was carried out to evaluate the accuracy of spatial interpolators for mapping the distribution of organic carbon (weight %), an important indicator of marine sediments in the marine environment. Measurements of organic carbon were carried out in a network of 20 sampling sites in the Gulf of Gera, which is representative of a semi-enclosed and shallow marine ecosystem at the south-eastern part of the island of Lesvos, Greece. For the interpolators under study, the cross-validation error was calculated at each sampling station and calculation of the RMSE (root-mean-square error), the MAE (mean-absolute error) and the MBE (mean-bias error) was carried out to assess the accuracy of their performance. The results revealed the most appropriate interpolator for the given dataset which was then applied to develop the thematic map of the spatial distribution of organic carbon. Discussion on the potential increase of the surface accuracy is also carried out.