[R] (no subject)

[Tim Clark]

Dear List,

I am trying to plot date vs. time, but am having problems getting my y-axis 
labels how I want them.  When left on its own R plots time at 6 hour intervals 
from 03:00 to 23:00.  I am wanting 6 hour intervals from 2:00 to 22:00.  I 
realize yaxp doesn't work in plot(), so I am trying to get it to work in par().  
However, now I get the ticks where I want them but the time is output as a very 
big number (serial time?).  I have also tried axis() using at= and also get 
seriel time numbers.  Any suggestions on how to format time on an axis?

  mydat$Date<-as.POSIXct(as.character(mydat$Date), format=c("%m/%d/%Y"))
  mydat$Time<-as.POSIXct(as.character(mydat$Time), format=c("%H:%M:%S"))

  plot(mydat$DateTime,mydat$Time, xlab=c("Date"), ylab=c("Time"),
  xlim=c(min(mydat$DateTime),max(mydat$DateTime)),
  ylim=c(min(mydat$Time),max(mydat$Time)),
  yaxt="n",
  yaxs="i",
  pch=19, cex=.4,
  type="n")

  par(yaxp=c(as.POSIXct(as.character("02:00"), 
format=c("%H:%M")),as.POSIXct(as.character("22:00"), format=c("%H:%M")),5))
  axis(2)


Thanks,

Tim
 Tim Clark

Marine Ecologist
National Park of American Samoa