NCL Website header
NCL Home > Documentation > Functions > Lat/Lon functions

lonGlobeF

Generates longitudes and associated metadata for a global fixed grid.

Prototype

load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"  ; This library is automatically loaded
                                                             ; from NCL V6.2.0 onward.
                                                             ; No need for user to explicitly load.

	function lonGlobeF (
		nlon     [1] : integer or long,  
		name     [1] : string,           
		longname [1] : string,           
		units    [1] : string            
	)

	return_val [*] :  float

Arguments

nlon

A scalar integer equal to the number of longitudes desired.

As of version 6.0.0, this can be of type integer or long.

name

A string that will become the named dimension of the output (e.g. "lon").

longname

A string that will become the long_name of the output (e.g. "longitude").

units

A string that will become the units of the output (e.g. "degrees_north").

Return value

A one-dimensional array of size nlon. Default type float.

Description

Generates longitudes and associated metadata for a global fixed grid.

See Also

lonGlobeFo, latGlobeF, latGlobeFo

Examples

Example 1

Create a one-dimensional array of longitudes (coordinate array) starting at the Greenwich Meridian.

      mlon = 144
      lon  = lonGlobeF(mlon, "lon", "longitude", "degrees_east")
      print(lon) 
The above returns a 1D array of length mlon values.
Variable: lon
Type: float
Total Size: 576 bytes
            144 values
Number of Dimensions: 1
Dimensions and sizes:   [lon | 144]
Coordinates: 
            lon: [ 0..357.5]
Number Of Attributes: 2
  long_name :   longitude
  units :       degrees_east
(0)      0
(1)      2.5
(2)      5
(3)      7.5
(4)     10
[snip]
(140)   350
(141)   352.5
(142)   355
(143)   357.5

Note 1: if starting at the International Date Line is desired,

      lon = (/ lon - 180. /)  ; subtract 180 from all values 
      lon&lon = lon           ; update coordinates
      print(lon) 
The result:

Variable: lon
Type: float
Total Size: 576 bytes
            144 values
Number of Dimensions: 1
Dimensions and sizes:   [lon | 144]
Coordinates: 
            lon: [-180..177.5]
Number Of Attributes: 2
  long_name :   longitude
  units :       degrees_east
(0)     -180
(1)     -177.5
(2)     -175
(3)     -172.5
(4)     -170
[snip]
(140)    170
(141)    172.5
(142)    175
(143)    177.5
Note 2: If double precision is desired, set
     mlon@double = True