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lonFlip

Reorders the longitude coordinate variable.

Prototype

load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"

	function lonFlip (
		x  : numeric   
	)

	return_val [dimsizes(x)] :  typeof(x)

Arguments

x

An array of any dimensionality. The rightmost dimension must be the longitude dimension, which must be global and without a cyclic point. Currently, the size of the longitude dimension must be an even nummber.

Return value

The results are returned in an array of the same type and dimensionality as x.

Description

This function reorders (flips) the longitude coordinate variable of the input variable. The size of the longitude dimension must be an even nummber.

See Also

lonPivot

Examples

Example 1

Assume that:

   printVarSummary(t)

produces:

     Variable: t
     Type: float
     Total Size: 589824 bytes
	         147456 values
	    Number of Dimensions: 4
	    Dimensions and sizes:   [time | 1] x [lev | 18] x [lat | 64] x [lon | 128]
	    Coordinates: 
	      time: [  31..  31]
              lev: [4.8093..992.528]
	      lat: [-87.8638..87.8638]
	      lon: [ 0..357.1875] 
	    Number Of Attributes: 3
	      long_name :   temperature
	      units :       K
	      time_op :     average

Then the following code will reorder the variable about the center longitude:

   t = lonFlip(t) ; reorder
   printVarSummary(t)

will produce:

     Variable: t
     Type: float
     Total Size: 589824 bytes
                 147456 values
              Number of Dimensions: 4
	      Dimensions and sizes:   [time | 1] x [lev | 18] x [lat | 64] x [lon | 128]
	      Coordinates: 
                time: [  31..  31]
                lev: [4.8093..992.528]
		lat: [-87.8638..87.8638]
		lon: [-180..177.1875]
	      Number Of Attributes: 4
	        long_name :   temperature
		units :       K
		time_op :     average

If it is preferred to retain the original variable and create a new variable:

          ; create a new variable
   t_flip = lonFlip(t)
   printVarSummary(t_flip)

will produce:

     Variable: t_flip
     Type: float
     Total Size: 589824 bytes
                 147456 values
              Number of Dimensions: 4
	      Dimensions and sizes:   [time | 1] x [lev | 18] x [lat | 64] x [lon | 128]
	      Coordinates: 
                time: [  31..  31]
                lev: [4.8093..992.528]
		lat: [-87.8638..87.8638]
		lon: [-180..177.1875]
 
	      Number Of Attributes: 4
	        long_name :   temperature
		units :       K
		time_op :     average



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