Error in datatips in plot

I run the following command

plot([1 2],8388608*[1 1])

However when i put a marker on the two data points in the plot the y value is incorrect

Same for x value

plot(8388608*[1 1]+[0 1],8388608*[1 1],'r*')

Answer 1

[dpb]

This is a builtin feature of the way the datatips work...by default there seems to be a rounding to 6 significant digits with the 'auto' format setting.

hL=plot([1 2],8388608*[1 1],'*-');  % the example large integer plotted
xlim(xlim+0.1*[-1 1])               % stretch x so points aren't identically on boundaries
hAx=gca; 
hAx.YAxis.TickLabelFormat='%.1f';      % clean up y labels
hAx.YAxis.Exponent=0;
% the above is all just preliminaries; the issue about datatip display follows...
hL.DataTipTemplate

ans = 
  DataTipTemplate with properties:

    DataTipRows: [2×1 matlab.graphics.datatip.DataTipTextRow]
    Interpreter: 'tex'
       FontSize: 10
      FontAngle: 'normal'
       FontName: 'Helvetica'

hL.DataTipTemplate.DataTipRows

ans = 2×1 DataTipTextRow array with properties:
    Label
    Value
    Format

hL.DataTipTemplate.DataTipRows.Format

ans = 'auto'

ans = 'auto'

[hL.DataTipTemplate.DataTipRows.Format]=deal("%d","%d");

●

will work for the present integer values; can be adjusted as needed for specific data sets.

hL.DataTipTemplate.DataTipRows.Format

ans = '%d'

ans = '%d'

Since the property is a member of the line it can't be set until the line is drawn unless one makes a change in the root property of the graphics root. That's doable either at the global level or for a specific figure or session depending upon needs.