2008 Unidata NetCDF Workshop for Developers and Data Providers > The "Classic" NetCDF Data Model
3.3 CDL
CDL (Common Data Language) is text notation for netCDF objects and data.
netcdf example { // example of CDL notation
dimensions:
x = 3 ;
y = 8 ;
variables:
float rh(x, y) ;
rh:units = "percent" ;
rh:long_name = "relative humidity" ;
// global attributes
:title = "simple example, lacks some conventions" ;
data:
rh =
2, 3, 5, 7, 11, 13, 17, 19,
23, 29, 31, 37, 41, 43, 47, 53,
59, 61, 67, 71, 73, 79, 83, 89 ;
}
This example
specifies a netCDF dataset with two dimensions (x and
y), one variable (rh), two
variable attributes (units and
long_name), one global attribute (title), and some data values for
the variable.
- This example has only one variable, but multiple variables
may be included in a netCDF file.
- CDL comments follow "//" symbols. They are not part of netCDF
data.
To store comments about a variable or file, use a
variable attribute or global attribute.
- You can use the ncdump utility to get the CDL
form of a binary netCDF file (more on this later).
- You can use the ncgen utility to generate a
binary netCDF file from CDL (more on this later).
- This simple example neglects some recommended best practices for
netCDF data.
- NcML is an XML-based notation similar to CDL for netCDF data
2008 Unidata NetCDF Workshop for Developers and Data Providers > The "Classic" NetCDF Data Model