#####Sample R script to open "hcrut3V-JAS.nc", from NOAA/NCDC Paleoclimatology World Data Center.  Author: Eugene R. Wahl, 9-7-2010.
#####This script can also be used with minimal modification to open any file of the form "hcrut3X-YYY.nc".


#####NOTE:  The time values in files of the form "hcrut3X-YYY.nc" are ordered from the earliest year to the latest year.



#####This script was developed for R 2.8.1.  It likely is back-compatible with earlier versions of R, but this has not been systematically checked.



##source("PUT APPROPRIATE FILEPATH AND FILENAME HERE")  #USE THIS LINE TO SOURCE THIS FILE DIRECTLY IN R, ONCE FILEPATH AND FILENAME ARE SPECIFIED FOR LOCAL CIRCUMSTANCE.


# rm(list=ls()) #  Commented out, Remove pound sign to activate. ACTIVATION REMOVES ALL OBJECTS IN R WORKSPACE -- BE CAREFUL TO INSURE YOU WANT TO DO THIS.

library (ncdf)


##Set-up Information  


filepath<-("//Dinobast/paleo_fileshare/2000-reconstruction/HadCRUT3v/")  #REPLACE WITH APPROPRIATE FILEPATH FOR LOCAL CIRCUMSTANCE.

filename<-("hcrut3V-JAS.nc")


##Open netCDF File


nc<-open.ncdf(paste(filepath,filename,sep=""))
print (nc)

time<-get.var.ncdf(nc,"time")
dim(time)
time

zlev<-get.var.ncdf(nc,"zlev")  #elevation in relation to sea level
dim(zlev)
zlev

lat<-get.var.ncdf(nc,"lat")
dim(lat)
lat

lon<-get.var.ncdf(nc,"lon")
dim(lon)
lon

temp<-get.var.ncdf(nc,"surf_temp_anom")
dimnames(temp)<-list(lon,lat,time)
dim(temp)


nc_array_timelatlon<-array(dim=c(dim(time),dim(lat),dim(lon)))

for (i in 1:dim(lon)) {
  for (j in 1:dim(lat)) {
     nc_array_timelatlon[,j,i]<-temp[i,j,] }}

dimnames(nc_array_timelatlon)<-list(time,lat,lon)
dim(nc_array_timelatlon)


nc_array_latlontime<-array(dim=c(dim(lat),dim(lon),dim(time)))

for (i in 1:dim(lon)) {
  for (j in 1:dim(lat)) {
     nc_array_latlontime[j,i,]<-temp[i,j,] }}

dimnames(nc_array_latlontime)<-list(lat,lon,time)
dim(nc_array_latlontime)


##View R array for ~ continental United States for specific sample of years

nc_array_latlontime[lat<=47.5 & lat>=27.5,lon>=-122.5 & lon<=-62.5,time<=2009 & time>=2000]


##View R array for ~ Europe for specific sample of years

nc_array_latlontime[lat<=67.5 & lat>=37.5,lon>=-7.5 & lon<=42.5,time<=2009 & time>=2000]


#####END