Model description
The folder contains two subfolders:
 \MATLAB format – contains original model in MATLAB format.
 \ X3DGLayers – contains model data in X3DG format [Kuvshinov, 2008].
Brief description of data is given below.
In \MATLAB format folder one can find MODELVER4.mat, which is a common MATLAB MATfile. 'v7.3' format was used when saving to file, which provides support for data items greater than or equal to 2 GB on 64bit systems. The file contains 4 distinct data arrays as following.
LATGRID – 720x1440 element 2D grid (produced by meshgrid function) to store Latitudes of all 15 min x 15 min meshes.
LONGRID – 720x1440 element 2D grid (produced by meshgrid function) to store Longitudes of all 15 min x 15 min meshes.
ZGRID – 1000 element 1D array containing depth of centers of all model layers. In current version of the model each layer has 100 m thickness.
MODEL – 720x 1440x1000 element array of conductivity values (in Sm/m), specified on 15 min x15 min x 100 m 3D grid. Thus, each number corresponds to a cell, centered at latitude/longitude/depth points given in corresponding coordinate arrays.
This makes it fairly convenient to regrid data or plot any lateral slice via geoshow or similar mapping Toolbox function as a texture object.
In \ X3DGLayers the model data are available as 4 model layers, reinterpolated on 1x1 deg. Each layer is stored in separate ASCII file. Layer depth ranges are chosen to be:
 Layer 1: 0 – 5 km
 Layer 2: 5 – 20 km
 Layer 3: 2045 km
 Layer 4: 45 1 00 km
Latitude and Longitude arrays corresponding to conductivity points are
phi = [0.5 : 1.0 : 360];  Latitude
theta = [0.5 : 1.0 : 180]  Longitude
The files containing GG suffix in their names store conductivity grids arranged according to Geographic coordinates, while those with GM suffix  Geomagnetic (dipole) coordinates.
