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--- kvalobs:kvoss:system:qc2:8hdk376snf09zj37dk82s92:ncdf [2009-06-20 16:21:09]
paule
+++ kvalobs:kvoss:system:qc2:8hdk376snf09zj37dk82s92:ncdf [2022-05-31 09:29:32] (current)
@@ Line 1: / Line 1: @@
 ====== Installing ncdf in R ======
-**NB** a prerequisite is that the netcdf libraries are alreadz installed.
+**NB** a prerequisite is that the netcdf libraries are already installed.
 <code>
@@ Line 15: / Line 15: @@
   $ R CMD INSTALL ncdf
   $ history
+  ...
+  ...
+  # there are perhaps even easier ways to do this:
+  $ install.packages("gplots", dependencies = TRUE)
+  # no source was linked ... but the mirror choose automatically opens
+  # and one just selects a site and the install happens!
+  ...
+  $
 </code>
+Making use of ncdf in R
+<code>
+  $ R
+   Method='unspecified'
+   Shortname='outfile'
+   library(ncdf)
+   nd = open.ncdf("interpolations.nc")
+   x=get.var.ncdf(nd,"Original")
+   y=get.var.ncdf(nd,"Interpolations")
+   x[x==-1]=0
+   v <- array(x, length(x))
+   w <- array(y, length(y))
+   xx=x[!is.na(x) & x>=0 & x < 100]
+   yy=y[!is.na(x) & x>=0 & x < 100]
+   yyy=yy[!is.na(yy) & yy>=0 & yy < 100]
+   xxx=xx[!is.na(yy) & yy>=0 & yy < 100]
+   jpeg(filename=paste(Shortname,'jpg',sep='.'))
+   plot(xxx,yyy,pch=46,xlab='Original Value',ylab='Interpoltion',main=Method)
+   XC=cor(xxx,yyy)
+   ff <- lm(xxx ~ yyy)
+   ff$coefficients[1]
+   ff$coefficients[2]
+   z=ff$coefficients[1]*xxx + ff$coefficients[2]
+   #lines(xxx,z)
+   text(0,95,"Linear Regression",pos=4)
+   text(0,90,paste("Gradient =",format(ff$coefficients[1],digits=5)),pos=4)
+   text(0,85,paste("Intercept =",format(ff$coefficients[2],digits=5)),pos=4)
+   text(0,75,paste("Correlation coefficient =",format(XC,digits=5)),pos=4)
+   dev.off()
+</code>
+Alternatively, place the code in a file and run from the command line:
+<code>
+ $ Rscript plot_netcdf.R "Test Plot" OUTPUT
+</code>
+that will produce the file OUTPUT.jpg with the plot title "Test Plot".
+  * {{kvalobs:kvoss:system:qc2:8hdk376snf09zj37dk82s92:plot_netcdf.pdf|plot_netcdf.R}}