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Problems with labeling a set X axis in chron plots

4 messages · Neotropical bat risk assessments, somewhereondearth, David Winsemius +1 more

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I am having difficulties getting the X-axis labels (dates) to be as 
needed when plotting from chron

The help syntax from chron lists this example:

x <- chron(dates = c("02/27/92", "02/27/92", "01/14/92", "02/28/92"),


I have activity plots by time on the y-axis and the dates on the 
x-axis. What I need/want is that the dates remain the same for a give 
set of data i.e. 10/25/2006 to 03/30/2007 as with some data sets 
within this time frame there is no activity for all of the dates so 
each plot has a different set of dates.


Below works great but when I try to constrain the dates it crashes...

DF <- read.table(textConnection(Lines), header = TRUE, as.is = TRUE)
DF$Date <- chron(DF$Date)
DF$Time <- times(paste(DF$Time, 0, sep = ":"))
at <- c(0, 1, 2, 3, 4, 5, 6, 17, 18, 19, 20, 21, 22, 23, 24)
plot(Time ~ Date, DF, ylim = 0:1, yaxt = "n",main= "Centronycteris centralis")
axis(2, at/24, lab = paste(at, "00", sep = ":"), las = 1, cex.axis = .7)

Thanks to all here on the group,

Bruce Miller
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HI,

I couldn't get your problem exactly, but if you are looking for dates on
x-axis, then try using 
axis.Date() option.
 you can give the weekly, daily sequence if you like.( I am trying for a
6-hour sequence, but hasn't got it yet).
Neotropical bat risk assessments wrote:

  
    
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On Feb 16, 2009, at 6:11 PM, Neotropical bat risk assessments wrote:

            
On my machine I'm reasonably sure the R interpreter would respond to  
that input with a new line and a "+".
The actual code would be sooo helpful here.
"Constrain the dates" means  ... what?

And it seems very doubtful that the error message was anything like "I  
crashed".

Sign me perplexed;
David Winsemius
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Date class does not support times.  See R News 4/1 for
a discussion of the difference between different
classes.

On Mon, Feb 16, 2009 at 8:08 PM, somewhereondearth
<somewhereond.earth at gmail.com> wrote: