btyfil = 'wedge.bty';
interp_type = 'RS';

zmax = 380;
zmin = 20;

slope_range = 7200;
wedge_angle = atand( ( zmax - zmin ) / slope_range );
fprintf( 'Wedge angle = %.4f degrees \n', wedge_angle )

dx = 30.;
dy = 0.4;

xctr = 0;
xmin = -30;
xmax = +30;
x = ( xmin : dx : xmax ) + xctr;
nx = length(x);

yctr = 0; % dy/2;
ymin = -4.4;
ymax = +4.4;
y = ( ymin : dy : ymax ) + yctr;
ny = length(y);

z0 = 200;   % Depth at (0,0)
zy = z0 - y * 1000 * tand( wedge_angle );

% truncate the wedge
zy = max( zy, zmin );
zy = min( zy, zmax );
% zy = fliplr(zy);
z = repmat( zy(:), 1, nx );

Bathy.X     = x;
Bathy.Y     = y;
Bathy.Z = z;

writebdry3d( btyfil,  interp_type, Bathy )
figure; plotbdry3d( btyfil )