Work with NetCDF

Beni Stocker

2025-01-30

library(rgeco)
library(here)

## here() starts at /home/runner/work/rgeco/rgeco

Read

Read contents of a NetCDF file into a data frame

The variable name needs to be specified. You can obtain it by doing ncdump -h cwdx80_forcing_halfdeg.nc in the terminal.

df <- nc_to_df(
  here("data/cwdx80_forcing_halfdeg.nc"),
  varnam = "cwdx80_forcing"
  )

## Loading required package: dplyr

## 
## Attaching package: 'dplyr'

## The following objects are masked from 'package:stats':
## 
##     filter, lag

## The following objects are masked from 'package:base':
## 
##     intersect, setdiff, setequal, union

df

## # A tibble: 259,200 × 3
##          lon       lat cwdx80_forcing
##    <dbl[1d]> <dbl[1d]>          <dbl>
##  1     -180.     -89.8             NA
##  2     -179.     -89.8             NA
##  3     -179.     -89.8             NA
##  4     -178.     -89.8             NA
##  5     -178.     -89.8             NA
##  6     -177.     -89.8             NA
##  7     -177.     -89.8             NA
##  8     -176.     -89.8             NA
##  9     -176.     -89.8             NA
## 10     -175.     -89.8             NA
## # ℹ 259,190 more rows

This contains NA for cells that have no values.

df <- df |> 
  tidyr::drop_na()

df

## # A tibble: 57,345 × 3
##          lon       lat cwdx80_forcing
##    <dbl[1d]> <dbl[1d]>          <dbl>
##  1     -68.8     -55.2           178.
##  2     -67.2     -55.2           167.
##  3     -69.2     -54.8           140.
##  4     -68.8     -54.8           156.
##  5     -68.2     -54.8           155.
##  6     -67.8     -54.8           155.
##  7     -67.2     -54.8           156.
##  8     -66.8     -54.8           388.
##  9     -66.2     -54.8           404.
## 10     -69.2     -54.2           204.
## # ℹ 57,335 more rows