[rrd-users] graph blends into x-axe

[Martin T]

I have a following graph:
http://img151.imageshack.us/img151/2396/fodu.png As you can see, brown
line blends into the x-axe. There are no "--upper-limit" or
"--lower-limit" in "rrdtool graph" specified as I thought that graph
image should scale automatically. Or does it work in a way that if the
brown line minimum value is less than -30(for example -30.5 or -31)
the graph would scale itself automatically?

regards,
martin