How to plot Contour on Irregular boundary?

I have data of sidment and depth,I want to plot <E:\金山快盘\华东师范大学\毕业论文\数据\surfer\北槽中潮> I know the "Contourf"! but I only can do like that <E:\金山快盘\华东师范大学\毕业论文\数据\临时> there are simlar,but the second picture have no depth. my code is: load('北槽中潮') sand1=log10(sand); contourf(sand1(1:5,:),100,'linestyle','none') view(0,270) colorbar xlabel('时间序列') ylabel('水深')