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getfilevardims

Returns all dimension names associated with a variable on a supported file.

Prototype

	function getfilevardims (
		thefile [1] : file,    
		varname [1] : string   
	)

	return_val [*] :  string

Arguments

thefile

A reference to a file created from a call to addfile or addfiles. Thus, the file referenced must be one in the supported file format list.

varname

Single string name of variable.

Return value

Returns a one dimensional array of dimension names for a file variable. getfilevardims returns a missing value if no dimension names exist or the variable is not defined.

Description

Accesses dimension names of a user specified variable in a supported file format.

Examples

Consider a netCDF file where "ncdump -h Tstorm.nc" yields:

netcdf Tstorm {
dimensions:
        timestep = 64 ;
        lat = 33 ;
        lon = 36 ;
        timelen = 20 ;
variables:
        float t(timestep, lat, lon) ;
                t:_FillValue = -9999.f ;
        int timestep(timestep) ;
        float lat(lat) ;
        float lon(lon) ;
        char reftime(timelen) ;
                reftime:units = "text_time" ;
                reftime:long_name = "reference time" ;
}

To retrieve the dimension names of the variable "t" on the file, you can use the following code snippet:

   f     = addfile ("$NCARG_ROOT/lib/ncarg/data/cdf/Tstorm.cdf" , "r")
   dNames= getfilevardims(f,"t")  
   print (dNames)

This produces the output:

Variable: dNames
Type: string
Total Size: 12 bytes
            3 values
Number of Dimensions: 1
Dimensions and sizes:   [3]
Coordinates: 
(0)     timestep
(1)     lat
(2)     lon

Note: you can also accomplish the above with the following code snippet:

   f     = addfile ("$NCARG_ROOT/lib/ncarg/data/cdf/Tstorm.cdf" , "r")
   dNames= getvardims(f->t)  
   print (dNames)

This is more inefficient, however, because the reference "f->t" causes the variable "t" to be read off the file. In using "getfilevardims", only the dimension names are read off the file.