In NetCDF, variables are defined along dimensions and are said to have "coordinate variables" that define the (typically spatio-temporal) positions of the data's cells.
nc_coord_var(x, variable = NULL, ...)
# S3 method for class 'character'
nc_coord_var(x, variable = NULL, ...)
# S3 method for class 'NetCDF'
nc_coord_var(x, variable = NULL, ...)tibble with "variable", "X", "Y", "Z", "T", and "bounds" columns that reference variables by name.
This function attempts to identify the X, Y, Z, and T coordinate variables for each data variable in the provided NetCDF source. The NetCDF-CF attribute conventions are used to make this determination.
All variables that can be related to a spatio-temporal axis, including coordinate variables are returned. For coordinate variables, a "bounds" column is included in the response indicating which variable contains bounds information.
See http://cfconventions.org/cf-conventions/v1.6.0/cf-conventions.html#coordinate-system for more.
f <- system.file("extdata", "S2008001.L3m_DAY_CHL_chlor_a_9km.nc", package = "ncmeta")
nc_coord_var(f, "chlor_a")
#> # A tibble: 1 × 6
#> variable X Y Z T bounds
#> <chr> <chr> <chr> <chr> <chr> <chr>
#> 1 chlor_a lon lat NA NA NA
f <- system.file("extdata", "guam.nc", package = "ncmeta")
nc_coord_var(f)
#> # A tibble: 5 × 6
#> variable X Y Z T bounds
#> <chr> <chr> <chr> <chr> <chr> <chr>
#> 1 RAINNC_present XLONG XLAT NA Time NA
#> 2 Time NA NA NA Time time_bnds
#> 3 T2_present XLONG XLAT NA Time NA
#> 4 U10_present XLONG XLAT NA Time NA
#> 5 V10_present XLONG XLAT NA Time NA