How to visualize a map from a netcdf file?

Question

I have a netcdf file that I would like to just visualize the soil depth map

   [1] \"file C:\\\\Users\\\\SoilDepth-gswp.nc has 3 dimensions:\"
     [1] \"x           


        

Answer 1

library(ncdf)
# I'm assuming this is the netcdf file you are working with:
download.file("http://dods.ipsl.jussieu.fr/gswp/Fixed/SoilDepth.nc", destfile="SoilDepth.nc")
soil <- open.ncdf("SoilDepth.nc")
#The way to extract a variable is as following:
soil$var[[3]] -> var3 # here, as shown in your question, SoilDepth is the 3rd variable
get.var.ncdf(soil, var3) -> SoilDepth

dim(SoilDepth)
[1] 15238

As was said in the summary for your netcdf file, the variable SoilDepth depends on dimension land only and not on x and y so I'm not sure where does that leave you when it comes to plotting this dataset.

Edit

It turns out there is a key that links x, y and land:

download.file("http://dods.ipsl.jussieu.fr/gswp/Fixed/landmask_gswp.nc", destfile="landmask.nc")
landmask <- open.ncdf("landmask.nc")
landmask$var[[3]] -> varland
get.var.ncdf(landmask, varland) -> land
sum(land==1)
[1] 15238

So in order to plot:

# The values where stored in an expected order, hence the transpose
land = t(land)
land[land==1] <- SoilDepth
land[land==0] <- NA
land = t(land)
image(land)