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wrf_user_latlon_to_ij

Finds the nearest model grid indices (i,j) to the specific location.

Available in version 4.3.1 or later.

Prototype

load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"
load "$NCARG_ROOT/lib/ncarg/nclscripts/wrf/WRFUserARW.ncl"

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

	return_val [2] :  integer

Arguments

nc_file

Input netCDF file name.

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 locations 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 missing (-999).

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.

WRF-related questions should be sent to wrfhelp@ucar.edu.

See Also

wrf_latlon_to_ij

Examples

Example 1

  load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"
  load "$NCARG_ROOT/lib/ncarg/nclscripts/wrf/WRFUserARW.ncl"

  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:

http://www.mmm.ucar.edu/wrf/OnLineTutorial/Graphics/NCL/