Please help

Hi Pascal,
        I think I figure it out.
        By doing the following, I can made "lon" & "lat" become a class of dim.ncdf:
         lon <- seq(from=140.0251, to=146.6751, length.out=241)
         lat <- seq(from=-38.975, to=-31.025, length.out=160)
         x=dim.def.ncdf("Lon","degreesE",as.double(lon))
          y=dim.def.ncdf("Lat","degreesN",as.double(lat))

       However, after running the script, there is a error I really unable to understand:
          error at data.frame(..., check.names = FALSE) :
          parameter value mean different rows 0, 31981

       If you can understand what the problem is, please as kind as offer me a direction.



Many thanks,
Jun

Date: Wed, 4 Jul 2012 10:39:29 +0100
From: kridox at ymail.com
Subject: Re: [R] Please help
To: chenshong at hotmail.com
CC: r-help at r-project.org

Hello,

Following lines are wrong:

x=dim.def.ncdf("Lon","degreesE",140.0251:146.6751)
y=dim.def.ncdf("Lat","degreesN",(-31.025):(-38.975))

You have 241 longitudes and 160 latitudes.
lon <- seq(from=140.0251, to=146.6751, length.out=241)
lat <- seq(from=-38.975, to=-31.025, length.out=160)

Regards



----- Mail original -----
De : Jun Chen <chenshong at hotmail.com>
? : r-help at r-project.org
Cc :
Envoy? le : Mercredi 4 juillet 2012 10h52
Objet : [R] Please help


Dear All,
           I am a research student in environment. I have only little programming knowledge. I am currently doing the last project about rainfall impact on ground water quality in an area. It happens that I have to use R to read rainfall data (3 dimension) from ASC file (*.asc), and then write them into one NCDF file (*.nc).

           I have been working very hard on study R, but I still can not fix the problem. Could someone please as kind as point out that what the problems are in my R script?

         Firstly, this is an example of data in asc file:
                     NCOLS      241

                     NROWS      160

                     XLLCORNER    140.00012207031

                     YLLCORNER  -39.000000000000

                     CELLSIZE    0.50000000000000E-01

                     NODATA_VALUE  -99.00000

                     166.30  160.87  155.23  149.33  143.83  138.52  133.29  128.34  123.76  119.21

                     115.06  110.90  107.22  103.69  100.40  97.29  94.58  92.15  90.00  87.91

                     86.20  84.57  83.22  81.94  81.11  80.38  79.37  78.73  79.70  79.62
           -----------------------------------------------------------------------------------------------------------------------



           And then this is the script I wrote:

setwd("E:/grid")

#defining dimension

x=dim.def.ncdf("Lon","degreesE",140.0251:146.6751)

y=dim.def.ncdf("Lat","degreesN",(-31.025):(-38.975))

t=dim.def.ncdf("Time","1968-01",1:12,unlim=TRUE)



#setup variable

varmr=var.def.ncdf("mr","mm",list(x,y,t),-99.00,

longname="monthly rainfall")


#create ncdf file

ncnew=create.ncdf("rainfall.nc", varmr)


#read input

files=list.files(pattern=".asc")

mrain=matrix(0:0,0,3)


for(i in files)

{rainfall=data.frame(readAsciiGrid(i))

   mrain=cbind(mrain,rainfall)

}

put.var.ncdf(ncnew, mrain)


close.ncdf(ncnew)

-------------------------------------------------------------------------------

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Many thanks,
Jun




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