40 40 40          // number of points (nx, ny, nz) in (northing, easting, depth) z pos down
32.5 32.5 1e-1    // offset in x, y, z (location of first calculation)
5 5 5 5 5 5 5 5 5 5 5 4 3 2 1 .5 .5 .5 .5 .5 .5 .5 .5 .5 1 2 3 4 5 5 5 5 5 5 5 5 5 5 5 // x direction point spacing, in metres, (nx-1) 
5 5 5 5 5 5 5 5 5 5 5 4 3 2 1 .5 .5 .5 .5 .5 .5 .5 .5 .5 1 2 3 4 5 5 5 5 5 5 5 5 5 5 5 // y direction point spacing, in metres, (nx-1) 
.1 .1 .1 1 1 1 1 1 1 1 1 1 1 2 2 2 3 3 3 4 4 4 4 4 4 5 5 5 5 5 5 5 5 5 5 5 5 5 5       // z direction point spacing, in metres, (nz-1)