Boxplot with scaled x-axis?

I'm trying to plot temperature data that is dependent on concentration (with temperature being the y axis and concentration the x). How do I create a plot that is scaled for the x variables (such that if some concentrations are closer the boxes are also closer)? I'm loading large sets of data and the previous examples I've seen are only drawn matrixes. Any help is appreciated. Thanks!

Answer 1

[Cris LaPierre]

Use boxchart and specify the xgroupdata input.

boxchart(xgroupdata,ydata)

Here's an example that orders and spaces the groups based on Month

tsunamis = readtable('tsunamis.xlsx');
tsunamis(1:8,["Month","Cause","EarthquakeMagnitude"])

ans = 8×3 table
    Month          Cause           EarthquakeMagnitude
    _____    __________________    ___________________

     10      {'Earthquake'    }            7.6        
      8      {'Earthquake'    }            6.9        
     12      {'Volcano'       }            NaN        
      3      {'Earthquake'    }            8.1        
      3      {'Earthquake'    }            4.5        
      5      {'Meteorological'}            NaN        
     11      {'Earthquake'    }              9        
      3      {'Earthquake'    }            5.8        

idx = contains(tsunamis.Cause,'Earthquake');
earthquakes = tsunamis(idx,:);
% Delete one month of data to show gap in figure
earthquakes(earthquakes.Month==3,:) = [];
boxchart(earthquakes.Month,earthquakes.EarthquakeMagnitude)

figure
earthquakes = tsunamis(idx,:);
% Change spacing of one group by adjusting the month number
earthquakes.Month(earthquakes.Month==3) = 2.5;
boxchart(earthquakes.Month,earthquakes.EarthquakeMagnitude)

[Cris LaPierre]

Just a comment. The xaxis here is optimized for categorical data, meaning X is really group number (integer values). The resulting output may not look like you want. This means you might have to adjust other parameters to account for your xgroupdata (e.g. BoxWidth).

tsunamis = readtable('tsunamis.xlsx');

idx = contains(tsunamis.Cause,'Earthquake');
earthquakes = tsunamis(idx,:);
earthquakes.Month=earthquakes.Month/10;
% BoxWidth uses default width, though X scale is now .1-1.2
boxchart(earthquakes.Month,earthquakes.EarthquakeMagnitude)

% Adjust BoxWidth to compensate
figure
boxchart(earthquakes.Month,earthquakes.EarthquakeMagnitude,'BoxWidth',0.05)