Cumulative sum by month

Basically I am wanting to recreate this figure but with the cumulative sum plotted at monthly intervals - i.e. more line detail is wanted in between the year ticks.

I have this code which creates the above figure:

    long = data(:,1) ;
    lati = data(:,2) ;
    year = data(:,3) ; 
    month = data(:,4) ; % year and month are in numerical form - e.g. 1985 01 
    mag = data(:,6) ;

 for i = 1:length(mag)
    if mag(i) < 3 
        mag(i) = NaN ;
        lati(i) = NaN ;
        long(i) = NaN ;
        year(i) = NaN ;
        month(i) = NaN ;
    end
 end

    cum_year = [1985:1:2015] ;
    n = zeros(length(cum_year),1) ;
    cum_year = cum_year' ;

    for j = 1:length(n)
     for i = 1:length(mag) ;
         if year(i) == cum_year(j)
             n(j) = n(j)+1 ;

         end
     end
    end

    year_sum = zeros(length(n),1) ;    
    for i = 1:length(n) ;
       year_sum(i) = sum(n(1:i)) ;
    end

figure ; 

plot(cum_year(1:24),year_sum(1:24),'b','LineWidth',1.5) ;
hold on
plot(cum_year(24:29),year_sum(24:29),'Color',[0.0 0.8 0.3],'LineWidth',1.5) ;
plot(cum_year(29:31),year_sum(29:31),'r','LineWidth',1.5) ;

So is there anyway of a cumulative sum on a monthly basis, where the year is changing?

[Stephen23]

Continued from this question:

http://www.mathworks.com/matlabcentral/answers/267677-how-do-i-perform-cumulative-adding-of-data-by-month-and-then-plot-it-by-year

Answer 1

[Star Strider]

I don’t entirely understand what you want. I would simply replace the stairs call (in my previous code) with a plot call to get a continuous line:

plot(PlotMtx(:,1), PlotMtx(:,2), '-g', 'LineWidth',2)

It would be possible to write code to reproduce your plot if I had all the data that created it.