NCL Home > Documentation > Functions > WRF

wrf_user_latlon_to_ij

Finds the nearest WRF-ARW model grid indexes (i,j) to the specific location (deprecated).

Prototype

load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"      ; These two libraries are automatically
load "$NCARG_ROOT/lib/ncarg/nclscripts/wrf/WRFUserARW.ncl"    ; loaded from NCL V6.4.0 onward.
                                                              ; No need for user to explicitly load.

	function wrf_user_latlon_to_ij (
		nc_file    : file,     
		latitude   : numeric,  
		longitude  : numeric   
	)

	return_val [2] :  integer

Arguments

nc_file

Reference to an input netCDF file opened with addfile.

latitude
longitude

Scalars for specific latitude,longitude points. If the input values are outside the model domain, then the appropriate return values will be set to missing (-999).

Return value

An integer array with 2 elements that holds the closest y/x position to the input latitude/longitude. The first element will be associated with latitude, and the second with longitude.

Description

This function was deprecated in NCL version 5.1.0. Use wrf_user_ll_to_xy instead.

This function locates the closest y/x point to the input latitude/longitude. If the input values are outside the model domain, then the appropriate return values will be set to the default missing value for an integer (-999 for versions 5.2.x and earlier, -2147483647 for versions 6.x and later).

wrf_user_latlon_to_ij is part of a library of functions and procedures in WRFUserARW.ncl written to help users plot ARW WRF model data.

Examples

Example 1

  a = addfile("wrfout_d01_2000-01-24_12:00:00.nc","r")

  loc  = wrf_user_latlon_to_ij(a, 40.0, -100.0)
  print("Y/X location is: " +loc)

You can see some other example scripts and their resultant images at: