MATLAB: Matlab doesn’t change MarkerSize

markersize

Hi all,
I know this is a basic one, but for some reason when I plot a figure, certain markers don't change their Size. The code that I use is the following:
plot(datos(index,i+1),headers(1,i+1),'sk','MarkerSize',4,'LineWidth',.25,'MarkerFaceColor',[R G B]);
or
 plot(datos(index,i+1),headers(1,i+1),'pk','MarkerSize',4.5,'LineWidth',.25,'MarkerFaceColor',[R G B]);
When I set the MarkerSize for a square or pentagram shape they always end up in a size 2.9×2.9 (squares) or size 4.2×4.06 (pentagram). I'm saving the figure as a PDF with "print(fig1,saveString,'-dpdf','-fillpage');" don't know if that matters but I thought of mentioning it.
Thanks in advanced,
Carlos TM

Best Answer

The unit of 'MarkerSize' is 'points' which is typically 1/72 inch. Depending on your OS, there are usually 96 pixels per inch. If you do the math on various marker sizes - and assume that apparent size of a marker is floor of its pixel size - the following sheds a little light:
pts = 4:.1:5;
in = pts./72;
pix = in.*96;
[pts;in;pix]
ans =
  4.0000    4.1000    4.2000    4.3000    4.4000    4.5000    4.6000    4.7000    4.8000    4.9000    5.0000
  0.0556    0.0569    0.0583    0.0597    0.0611    0.0625    0.0639    0.0653    0.0667    0.0681    0.0694
  5.3333    5.4667    5.6000    5.7333    5.8667    6.0000    6.1333    6.2667    6.4000    6.5333    6.6667
This would make me believe that 4.5 looks larger than 4.0-4.4, but it could be a little round-off error in MATLAB's calculation vs. my assumed algorithm above. Try 4.6 for your 'MarkerSize' and see if that helps.
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