[GRASS5] Question on resolution

[Sharyn Namnath]

I have a question on the ewres & nsres values. I'm not clear on what they
represent and if they correspond to the dpi of the created PNG file.  I'm
creating a 1024 x 512 file for display, but I am trying to figure out the
optimum nsres & ewres values to set my region with (using g.region) so that
the rasterization (d.rast) is as fast as possible.  I'm pretty new at this
so I'm still muddling about..

Thanks for any help,
- sharyn