I get bad resolution when saving my plot with filled circles as .pdf or .eps

Even though the plot looks okay when shown in MATLAB, the filled circles seem to lose their resolution when I save them. To see the difference, please open the saved PDF or EPS file. Thank you for your advice.

The code:

clear all, close all

sysX = 30; sysY = 30;
xyb = [5 +1j*5 ,  5+1j*15 ,  5+1j*25, ...
       15+1j*5 , 15+1j*15 , 15+1j*25, ...
       25+1j*5 , 25+1j*15 , 25+1j*25];
xym = sysX*rand(1,18);

fig = 0; 
fig = fig + 1; figure(fig);
for i = 1:length(xyb),
    plot(xyb(i),'ko'), axis([0 sysX 0 sysY]), hold on
    plot(xym,'ko','MarkerSize',4,'MarkerFaceColor','k')
end
xlabel('Unit 1');
ylabel('Unit 2');
legend('Type 1','Type 2','Location','North','Orientation','Horizontal');
set(gca,'Units','pixels');
filenameStrEps = 'testFigure.eps';
filenameStrPdf = 'testFigure.pdf';
saveas(gcf,filenameStrEps)
saveas(gcf,filenameStrPdf)

Answer 1

[Ben11]

You might want to use print instead of save, and set the resolution to something acceptable to you:

print(gcf, '-dpdf', '-r600', filenameStrPdf)

[Gunnar]

Thank you for your answer, Ben. However, I only see a marginal improvement for the PDF. In the case of EPS, it seems to have a much more positive effect.

[Ben11]

ok then sorry!