Dissapearing data?

All,

I have noticed a bizarre occurrence. I have a fairly
dense plot that when viewed in a large figure I can see all of the data, but as
I resize the plot smaller I start to see some of the data disappear. I
understand that there is a pixel-space issue, but to someone who might not
realize that their plot is physically too small, they might think that what
they see is really true. In the attached example script (with data) you
can see this behavior. When the plot gets small enough you never see
anything reach the y value of 20.0. I found this to be a little
disconcerting and was wondering if I can get a detailed explanation as to what
I am seeing.

Thanks,

–James Evans

shrinkage.tgz (50.7 KB)