Hi Michael,
Thanks for the reply.
The data file can be rechieved from the following link:

ftp://ftp.wiley.com/public/sci_tech_med/spatio_temporal_data

SST011970_032003.dat<ftp://ftp.wiley.com/public/sci_tech_med/spatio_temporal_data/SST011970_032003.dat>
SSTdata_descrip.txt<ftp://ftp.wiley.com/public/sci_tech_med/spatio_temporal_data/SSTdata_descrip.txt>
SSTlandmask.dat<ftp://ftp.wiley.com/public/sci_tech_med/spatio_temporal_data/SSTlandmask.dat>
SSTlonlat.dat<ftp://ftp.wiley.com/public/sci_tech_med/spatio_temporal_data/SSTlonlat.dat>
I will try the suggestion you provided, and wait for further comments.

Thank you very much

Fred

On Wed, Aug 17, 2011 at 4:38 PM, Michael Sumner <mdsumner@gmail.com> wrote:

> At a guess, for a given latitude you could do this where "x" is a
> data.frame with columns Longitude, Latitude, Time1, ..., TimeN
>
> x1 <- x["Latitude" == -29, ]
>
> ## very simplistically
>
> ## drop Latitude, and order by Longitude (assuming Time columns are in
> the right order)
> x2 <- as.matrix(x1[order(x1$Longitude),  -2]
>
> image(x2)
>
> ## with a bit more work, but big assumptions
>
> lon <- sort(x1$Longitude)
> tm <- as.numeric(colnames(x2)[-1])
>
> image(lon, tm, x2, main = "Latitude -29", xlab = "Longitude", ylab =
> "Time")
>
>
> There's a lot of guessing here for us, can you describe the file more
> exactly or provide a link to at least one latitude's worth?
>
> The Spatial classes in sp provide much more structured support for
> these grids, and the spacetime package even more for generalizing
> further - but they rely on exactly regular grids, which it looks like
> you have here.
>
> Cheers, Mike.
>
>
> On Wed, Aug 17, 2011 at 1:45 PM, Jianyun Wu <jianyun.fred.wu@gmail.com>
> wrote:
> > Dear Experts,
> >
> > I am trying to plot the Hovmueller Diagram (example below), which is time
> > vs. longitude in R.
> >
> >
> http://www.esrl.noaa.gov/psd/cgi-bin/hovmoller/timeplot.pl?var=air&level=1000&mon1=1&mon2=1&dy1=1&dy2=31&yr1=2010&yr2=2011&datatype=operational&type=mean&fxdlon=no&postscript=no&lon1=&lon2=&lat1=&lat2=&cint=&lowr=&highr=&size=100&Submit=Create+Plot
> >
> > But I couldn't make it work at the moment. Could anyone please suggest me
> > which package or function in R can plot such a graph?
> >
> > The data file on hand is like:
> >
> > Longtitude   Latitude   Time1.....................TimeN
> >   124            -29
> >   126            -29          .......................................
> >   128            -29
> >     ..             . .
> >
> > 2520 spatial locations corresponding to an 84 (longitude) by 30
> (latitude)
> > grid with 2 degree x 2 degree spacing.
> >
> > Thank and Regards
> >
> > Fred
> >
> >        [[alternative HTML version deleted]]
> >
> > _______________________________________________
> > R-sig-Geo mailing list
> > R-sig-Geo@r-project.org
> > https://stat.ethz.ch/mailman/listinfo/r-sig-geo
> >
>
>
>
> --
> Michael Sumner
> Institute for Marine and Antarctic Studies, University of Tasmania
> Hobart, Australia
> e-mail: mdsumner@gmail.com
>

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