[gradsusr] how to customize tick mark interval and labels in date/time axis

[Qian Hao]

Dear all, are there anyway to customize the tick mark interval and
labels in the time axis? I know that we can use:
set xlabs lab1 | lab2 | ... | labN
it will place the N labels on the x axis with equal distance.But how
to customize this behavior? I have already searched the maillist with
only one thread matched:
http://gradsusr.org/pipermail/gradsusr/2007-July/005182.html
and nobody has replied to it.

-- 
Hao Qian
Key Laboratory of Ocean Circulation and Waves (KLOCAW)
Institute of Oceanology, Chinese Academy of Sciences
No.7 Nanhai Road, Qingdao 266071, P.R.China
Phone: +86-18753220258