output.png from gnuplot is not as good as the figure from prompt shell

Question

I often plot graphs in gnuplot prompt shell, like this:

gunuplot> plot sin(x) with linespoints pointtype 3

and the figure showe

Answer 1

The default size of the PNG image generated gnuplot with the PNG terminal is 640x480 pixels. This resolution in certain cases may result in "pixelated" graphs which are not as nice as those produced on screen with the default (wxt) terminal.

You can change the resolution of the output image using the size option:

set terminal png size    

where x and y are the desired numbers of pixels along the horizontal and vertical axis, respectively. For example:

set terminal png size 1024,768

Please note that, images with larger resolution will result in proportionally larger files on disk. Alternatively you can try to use non-raster terminals like "post eps" or "pdf" if available on your machine, which may give you high quality scalable and (relatively) portable images without a large disk footprint.