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.
