I got part way through but realized that I am not clear as to how the data is being represented in your graph.
The partial framework I developed follows. Depending on what is in your graph, it might potentially need significant changes.
filename = 'NameOfFig.fig';
fig = openfig(filename);
obj_with_x = findobj(fig, '-property', 'XData');
if isempty(obj_with_x)
fprintf('Opps, file "%s" has no objects with XData\n', filename);
else
if ~iscell(obj_with_x)
obj_with_x = {obj_with_x};
end
xvals = cellfun(@(OBJ) obj.XData(:), obj_with_x, 'uniform', 0);
yvals = cellfun(@(OBJ) obj.YData(:), obj_with_y, 'uniform', 0);
xvals = cell2mat(xvals);
yvals = cell2mat(yvals);
end
