MATLAB: Creating a series of x-y plots

x-y plots

Hey, I want to make a set of x-y plots based on data with the following format:
"Tag    Property-A    Property-B
X1        A11           B11    
X1        A12           B12
...........................
X2        A21           B21
..........................."
Properties A and B are the x and y variables. Each tag is matched with several pairs of A and B, and each plot should include data with a specific tag. Since there are a good many tags, it is impossible to manually separate the data. So is there any commands in Matlab that can be used to create such plots? I hope I have clearly stated my question. Thanks. Lin
P.S. I just realized the format couldn't display properly, so I'll briefly describe the data: there are three columns of data: Tag, Property A, Property B. Each tag encompasses a certain amount of x-y pairs, and the purpose is to make every one of the tags a plot showing the scattered x-y relationship.
A sample data file is attached.

Best Answer

If you have three columns, call them station, depth, and salinity, you could plot all the station 1 data as red pentograms, station 2 as blue squares, etc, like this:
plot(salinity(station==1),depth(station==1),'rp-'); 
hold on
plot(salinity(station==2),depth(station==2),'bs-'); 
plot(salinity(station==3),depth(station==3),'mo-'); 
plot(salinity(station==4),depth(station==4),'k^-'); 
plot(salinity(station==5),depth(station==5),'gx-'); 
legend('station 1','station 2','station 3','station 4',...
    'station 5','location','southwest')
legend boxoff 
box off
ylabel('depth (m)')
xlabel('salinity (psu??)') 
set(gca,'ydir','reverse')
axis tight
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