[R-sig-Geo] What is the Coordinate Reference System?

[Sergio Ibarra]

Greetings,

I'm want to read NetCDF spatial data from a meteorological model (WRF
model). The NetCDF can have one of these three projections:

Polar stereographic
Lambert conformal
Mercator projection

(See figure
https://user-images.githubusercontent.com/27447280/41389756-ed23f91a-6f68-11e8-961e-6ba901913c54.png
)

What is the  Coordinate Reference System for each case?

Thanks!

Here an example with ncdf4 and raster:

library(ncdf4)
library(raster)
a <- tempfile()
download.file(url = "
http://www.unidata.ucar.edu/software/netcdf/examples/wrfout_v2_Lambert.nc",
              destfile = a) #78 Mb
wrf <- nc_open(a)
paste("The file has",wrf$nvars,"variables")
paste("The file has",names(wrf$var))
lat <- ncvar_get( wrf, "XLAT" )
lon <- ncvar_get( wrf, "XLONG" )
t2 <- ncvar_get( wrf, "T2" ) - 273.15
dim(t2) #73 60 13
#image
image(t2[, , 12])
# raster
rt2 <- raster(t(t2[1:dim(t2)[1],
                   dim(t2)[2]:1,
                   12]),
              xmn = min(lon),
              xmx = max(lon),
              ymn = min(lat),
              ymx = max(lat),
*              crs="+init=epsg:4326") # ???*
spplot(rt2)



-- 
​Sergio Ibarra Espinosa
Post Doc
PhD in Atmospheric Sciences
Instituto de Astronomia, Geofísica e Ciências Atmosféricas
Universidade de São Paulo
Rua do Matão, 1226
São Paulo-SP - Brasil -
05508-090
+55-11-97425-3791
Skype: sergio_ibarra1

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