Errors in Gnuplot PDF output

Question

I'm trying to plot data with Gnuplot where all data values are positive. However, when plotting to PDF some of the output values appear negative under the x-axis: http://tinypic.com/r/14iztbs/7

This does not happen when plotting to PNG.

Reducing the line width helps to mitigate this issue, but this is not really a solution.

How can i print with some wider line width, without having these artifacts in the output? The strange thing is that the "length" of these artifacts is longer than the line width.

Is this an error in Gnuplot?

Answer 1

This happens because the line joints are mitered by default in the pdf terminal, while they are rounded by default in the png terminal.

set terminal pdf rounded

Also see the gnuplot documentation (gnuplot> help set terminal pdf).