%% Simple plot of the model
%% This plot adds elements to current figure
%%
%%	Add to this code color plotting of velocities using 'imagesc()'
%% ======================================================================================
%%
%% Parameters:
%%	model - the model structure as described in code 'trace_ray'
%%	slowness - slowness vector corresponding to the model.
%%		The slowness is plotted as VELOCITY values, by using imagesc().
%%		If this parameter is not given, velocity is not plotted

function p = plot_model(model,slowness)

	hold on

	% lower-right corner of the model

	lr = model.xz0 + [ model.nx*model.dxz(1), model.nz*model.dxz(2) ];

	% generate grids of X and Y coordinates at the edges of the cells

	x = model.xz0(1) + model.dxz(1)*(0:model.nx);
	z = model.xz0(2) + model.dxz(2)*(0:model.nz);

	% plot velocities in color

	if nargin > 1			% slowness vector is given
		vgrid = vect2grid(model,slowness).^(-1);

		caxis([1.5, 3]);
		imagesc(x(2:end) - 0.5*model.dxz(1),z(2:end)- 0.5*model.dxz(2),vgrid);
		colorbar
		
	endif

	% horizontal lines

	for i=1:length(z)
		plot([model.xz0(1), lr(1)], [z(i),z(i)],'k-');
	end

	% vertical lines

	for i=1:length(x)
		plot([x(i),x(i)],[model.xz0(2), lr(2)],'k-' );
	end

	xlabel('X (m)')
	ylabel('Depth (m)')
end