Thank you for the kind reply. 1. The order of the dimension is reflected when used as print(ncin) function. This function has been used to have a quick look at the structure of the default netCDF file. 2. Firstly, I am in need of subsetting this netCDF file and then have to convert the slice into .csv format.
So far, I could read the netCDF file (variables and dimensions) and fragment the time into fields. Therefore, I would be grateful to get further help to reach the goal. Regards, Eeusha On Mon, Aug 28, 2017 at 11:56 PM, Roy Mendelssohn - NOAA Federal < roy.mendelss...@noaa.gov> wrote: > Two questions: > > 1. Is the order of the dimensions shown what is shown if you look at > str(ncin) - I mean shown at the end where it describes the variable and its > dimensions? > > 2. Is you problem how to subset the netcdf file, how to write to the > .csv file, or both? > > -Roy > > > On Aug 28, 2017, at 2:21 PM, Eeusha Nafi <eshad...@gmail.com> wrote: > > > > I have a series of nertCDF files containing global data for a particular > > variable, e.g. tmin/tmax/precipiation/windspeed/relative > > humuidity/radiation etc. I get the following information when using > > *nc_open* function in R: > > > > datafile: https://www.dropbox.com/s/xpo7zklcmtm3g5r/gfdl_preci.nc?dl=0 > > > > File gfdl_preci.nc (NC_FORMAT_NETCDF4_CLASSIC): > > > > 1 variables (excluding dimension variables): > > float prAdjust[lon,lat,time] > > _FillValue: 1.00000002004088e+20 > > missing_value: 1.00000002004088e+20 > > comment: includes all types (rain, snow, large-scale, > > convective, etc.) > > long_name: Bias-Corrected Precipitation > > units: kg m-2 s-1 > > standard_name: precipitation_flux > > > > 3 dimensions: > > lon Size:720 > > standard_name: longitude > > long_name: longitude > > units: degrees_east > > axis: X > > lat Size:360 > > standard_name: latitude > > long_name: latitude > > units: degrees_north > > axis: Y > > time Size:365 *** is unlimited *** > > standard_name: time > > units: days since 1860-1-1 00:00:00 > > calendar: standard > > axis: T > > > > 14 global attributes: > > CDI: Climate Data Interface version 1.7.0 ( > http://mpimet.mpg.de/cdi) > > Conventions: CF-1.4 > > title: Model output climate of GFDL-ESM2M r1i1p1 Interpolated > > to 0.5 degree and bias corrected using observations from 1960 - 1999 > > for EU WATCH project > > CDO: Climate Data Operators version 1.7.0 ( > http://mpimet.mpg.de/cdo) > > product_id: input > > model_id: gfdl-esm2m > > institute_id: PIK > > experiment_id: historical > > ensemble_id: r1i1p1 > > time_frequency: daily > > creator: isi...@pik-potsdam.de > > description: GFDL-ESM2M bias corrected impact model input > > prepared for ISIMIP2 > > > > Now I want to extract a subset from this dataset using pair of lon and > lat > > points, e.g., (12.875, -11.625) & (8.875, 4.125) and convert the file > into > > .csv format. > > > > so far I could make up to this step: > > > > # load the ncdf4 package > > library(ncdf4) > > # set path and filename > > setwd("D:/netcdf") > > ncname <- "gfdl_preci" > > ncfname <- paste(ncname, ".nc", sep = "") > > dname <- "prAdjust" > > # open a netCDF file > > ncin <- nc_open(ncfname) > > print(ncin)# get longitude and latitude > > lon <- ncvar_get(ncin,"lon") > > nlon <- dim(lon) > > head(lon) > > > > lat <- ncvar_get(ncin,"lat") > > nlat <- dim(lat) > > head(lat) > > > > print(c(nlon,nlat)) > > # get time > > time <- ncvar_get(ncin,"time") > > time > > > > tunits <- ncatt_get(ncin,"time","units") > > nt <- dim(time) > > nt > > tunits > > # get variable > > preci.array <- ncvar_get(ncin,dname) > > > > dlname <- ncatt_get(ncin,"prAdjust","long_name") > > > > dunits <- ncatt_get(ncin,"prAdjust","units") > > > > fillvalue <- ncatt_get(ncin,"prAdjust","_FillValue") > > > > dim(preci.array) > > # split the time units string into fields > > tustr <- strsplit(tunits$value, " ") > > > > tdstr <- strsplit(unlist(tustr)[3], "-") > > > > tmonth = as.integer(unlist(tdstr)[2]) > > > > tday = as.integer(unlist(tdstr)[3]) > > > > tyear = as.integer(unlist(tdstr)[1]) > > > > chron(time, origin = c(tmonth, tday, tyear)) > > > > *Any help would be appreciated!!* > > > > [[alternative HTML version deleted]] > > > > ______________________________________________ > > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > > https://stat.ethz.ch/mailman/listinfo/r-help > > PLEASE do read the posting guide http://www.R-project.org/ > posting-guide.html > > and provide commented, minimal, self-contained, reproducible code. > > > > ********************** > "The contents of this message do not reflect any position of the U.S. > Government or NOAA." > ********************** > Roy Mendelssohn > Supervisory Operations Research Analyst > NOAA/NMFS > Environmental Research Division > Southwest Fisheries Science Center > ***Note new street address*** > 110 McAllister Way > Santa Cruz, CA 95060 > Phone: (831)-420-3666 > Fax: (831) 420-3980 > e-mail: roy.mendelss...@noaa.gov www: http://www.pfeg.noaa.gov/ > > "Old age and treachery will overcome youth and skill." > "From those who have been given much, much will be expected" > "the arc of the moral universe is long, but it bends toward justice" -MLK > Jr. > > [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
