Combine multiple data series into a single series

Is there a way to combine multiple data series so that they only display as a single series in the Legend?

I have a function that uses 'plot' to plot multiple line segments. It can be thought of as a custom 'marker' shape class. Each data point is drawn using multiple line segments. I plot this (conceptually) single data series on the same plot as multiple other data series.

When I use the 'legend' function, each segment shows up as a separate element. So if I have plotted 2 series using the standard 'plot' function, and one using this custom function, with N data points, the legend thinks that there are N+2 data series. I want to treat this as 3 data series.

Answer 1

[Adam Danz]

Specify a vector of object handles in your call to legend.

https://www.mathworks.com/help/matlab/ref/legend.html#bt6ef_q-1-subset

Example

hold on
h(1) = plot(x,y); 
h(2) = plot(x2,y2); 
h(3) = plot(x3,y3); 
legend(h(1), 'data')

If you're using the 'DisplayName' property, you can use the legendUnq() FEX submission to represent only unique names in your legend.

Example

hold on
for i = 1:3
    h(i) = plot(rand(1,10), rand(1,10, 'o'), 'DisplayName', sprintf('Data_%d',i)); 
end
legend(legendUnq(gca))

[Peter]

Thanks, this is exactly what I was looking for. I assumed that you could pass the handle into 'legend' but I couldn't figure out how.

I ended up outputing the handle of the first segment from the custom plot function.

hold on
h(1) = plot(x,y); 
h(2) = plot(x2,y2); 
h(3) = plotCustom(data);  
 Legend{1}='series 1';
 Legend{2}='series 2';
 Legend{3}='series 3';
 legend(h,Legend)
 
 
 
     function[h]=plotCustom(data)
     ...
         h=plot([(xStart;xEnd],[yStart;yEnd],'color',c);
         h=h(1);%combine all plotted segments into a single handle, so that the legend treats this as a single series
     end

[Adam Danz]

One simplification I could suggest: if you use the 'DisplayName' property in your call to plot, you don't need to produce the "Legend" cell array.

function[h]=plotCustom(data)
      ...
      temph=plot([(xStart;xEnd],[yStart;yEnd],'color',c, 'DisplayName', sprintf('series %d', i)));  % assumes 'i' is available
      h(i)=temph(1);
      
     ...
     legend(h)
 end