For the WDMAM, available near-surface (aeromagnetic or marine magnetic survey) data, e.g. the gridded data compilation for the Arctic by the Geological Survey of Canada (Verhoef et al., 1996) have been used for the present version, called WDMAM 2007 (Korhonen et al., 2007).
The first option is to perform calculations on regularly spaced grids allowing for the compilation of probability maps.
Compilation... compilers?
Topographic information was retrieved from a compilation of global grid datasets including gravity and magnetic satellite surveys from the Shuttle Radar Topography Mission at the United States Geological Survey website (Shuttle Radar Topography Mission: United States Geological Survey 2015).
Instead, we collected the national compilation and rebuilt a grid over Europe.
The bathymetric/topographic grid layers were generated from a compilation of multisource height/depth data that includes: the GEBCO 30 Arc-second grid as a starting point, and the compilation of nautical maps of the Moroccan margin.
To build this model, we first reduced the size of the data set to a 0.2×0.2 degree cell size grid using the GMT function blockmedian applied on the compilation.
It was formed in 2003 and aims at collecting aeromagnetic and marine data worldwide to provide the scientific community with a compilation of these data on a global, 5-km cell size, grid.
At the end of the merging process, we obtain a compilation of all available data on a global 0.05×0.05 degree cell size grid—(i.e. roughly 5×5 km cell size), with no missing values.
This promises to provide a more nuanced heat map than presented in the existing compilations, which either consign an average temperature to an area defined by a grid square or, in the case of NASA, attempt a less ambitious interpolation.It will be interesting to see whether this makes it past the review process.
An attempt to improve, this grid was proposed by Maus et al. 2009 who constructed the EMAG2 grid using updated aeromagnetic and marine compilations and adding a priori information in the oceanic domain.
