Dear all, My name is Maria Lathouri and I am currently doing a PhD at Imperial College of London about time series of environmental variables in surface waters. I am trying to do some time plots with R but it seems that it is not working. The problem is that the time is not regular, for example, a small dataset can be seen below: Date pH 1/02/1998 5.5 5/03/1998 5 8/12/1998 6 1/02/1999 6.1 ... 08/10/2000 7.2 I have used the function >plot(DATE, pH) and then >lines(pH), but the line does not join the points. I have used many combinations, e.g. >plot(DATE, pH) and then >lines(DATE, pH), where I get a plot with full of lines inside or just >plot(pH) and then >lines(pH) where the line connects the points but in x-axis I do not have the DATE. It says Index from 0 to 80. Do you know if there is a function where I can have in x-axis the DATE (irregular dates) and in y-axis the variable with a continuous line, showing how it changes through time? I know that your time is valuable but I would appreciate it if you could help me. Thank you very much in advance for your time and help. I am looking forward to hearing from you. Sincerely yours Lathouri Maria [[alternative HTML version deleted]]
Try this (in reality you would use the commented line
in place of the subsequent line) and then read the three
zoo vignettes and R News 4/1.
library(zoo)
library(chron)
Lines <- "Date pH
1/02/1998 5.5
5/03/1998 5
8/12/1998 6
1/02/1999 6.1
08/10/2000 7.2"
# z <- read.zoo("myfile.dat", header = TRUE, format =
"%m/%d/%Y")
z <- read.zoo(textConnection(Lines), header = TRUE, format =
"%m/%d/%Y")
plot(z)
On Wed, Nov 12, 2008 at 10:40 AM, Lathouri, Maria
<m.lathouri06 at imperial.ac.uk> wrote:> Dear all,
>
> My name is Maria Lathouri and I am currently doing a PhD at Imperial
College of London about time series of environmental variables in surface
waters. I am trying to do some time plots with R but it seems that it is not
working.
> The problem is that the time is not regular, for example, a small dataset
can be seen below:
> Date pH
> 1/02/1998 5.5
> 5/03/1998 5
> 8/12/1998 6
> 1/02/1999 6.1
> ...
> 08/10/2000 7.2
>
> I have used the function >plot(DATE, pH) and then >lines(pH), but the
line does not join the points. I have used many combinations, e.g.
>plot(DATE, pH) and then >lines(DATE, pH), where I get a plot with full of
lines inside or just >plot(pH) and then >lines(pH) where the line connects
the points but in x-axis I do not have the DATE. It says Index from 0 to 80.
>
> Do you know if there is a function where I can have in x-axis the DATE
(irregular dates) and in y-axis the variable with a continuous line, showing how
it changes through time?
> I am trying to do some time plots with R but it seems that it > is not working. The problem is that the time is not regular, > for example, a small dataset can be seen below:> Date pH > 1/02/1998 5.5 > 5/03/1998 5 > 8/12/1998 6 > 1/02/1999 6.1 > ... > 08/10/2000 7.2> I have used the function >plot(DATE, pH) and then >lines(pH), > but the line does not join the points.lines() needs the same arguments as plot().> I have used many combinations, e.g. >plot(DATE, pH) and then > >lines(DATE, pH), where I get a plot with full of lines insideYou are on the right track here. You probably want something like plot(Date, ph, type="l") or plot(Date, ph, type="b") R will plot in the order of appearance, so you may want to sort the data.frame before plotting.> x-axis I do not have the DATE. It says Index from 0 to 80.Have a look at the structure of your data. str() will do that for you. I suspect that Date is a factor rather than a Date. Use as.Date() to fix that.> Do you know if there is a function where I can have in x-axis > the DATE (irregular dates) and in y-axis the variable with a > continuous line, showing how it changes through time?So in summary you probably want something like this: # make some example data df <- data.frame( d=c('2008-10-01','2008-10-12','2008-10-5','2008-10-31'), y=c(12.5, 17, 13.6, 23.345) ) # convert to Date, sort and plot df$d <- as.Date(df$d) df <- df[order(df$d), ] plot(df, type='l') cu Philipp -- Dr. Philipp Pagel Lehrstuhl f?r Genomorientierte Bioinformatik Technische Universit?t M?nchen Wissenschaftszentrum Weihenstephan 85350 Freising, Germany http://mips.gsf.de/staff/pagel