Re: Bug in the wrf_user_ll_to_ij function ????????

From: Mary Haley <haley_at_nyahnyahspammersnyahnyah>
Date: Tue Jun 12 2012 - 09:55:01 MDT

I'm fowarding this to wrfhelp@ucar.edu.

--Mary

On Jun 12, 2012, at 7:48 AM, BasitAli Khan wrote:

> Hi all,
>
> I am encountering this problem of converting latlon to ij coordinates using wrf_user_ll_to_ij function. When I convert max lat and long to ij coordinates, the function give me grid y_coordinates larger than total number of grid points in y_dimension. In the same way conversion of minimum longitude results in a negative number. However, the old latlon to ij conversion function "wrf_user_latlon_to_ij" does the conversion correctly.
>
> I wrote the following small code to recheck this. I used both old and new functions to show the difference. There are 651 x 651 grid points in the wrfout file.
>
>
> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"
> load "$NCARG_ROOT/lib/ncarg/nclscripts/wrf/WRFUserARW.ncl"
>
> begin
>
> f1 = addfile("/wrfout_d01_2006-06-02_13:00:00.nc","r")
>
> opts = True
>
> xLat_f1 = wrf_user_getvar(f1,"XLAT", 0)
> xLong_f1 = wrf_user_getvar(f1,"XLONG", 0)
>
> xLat_min = min(xLat_f1)
> xLat_max = max(xLat_f1)
>
> xLong_min = min(xLong_f1)
> xLong_max = max(xLong_f1)
>
> ; New ll_to_ij function
> min_loc_ll = wrf_user_ll_to_ij(f1,xLong_min,xLat_min,opts)
> max_loc_ll = wrf_user_ll_to_ij(f1,xLong_max,xLat_max,opts)
>
> print("min. x-coord fm ll func.: "+min_loc_ll(0)+"; min. y_coord fm ll func.: "+min_loc_ll(1))
> print("max. x-coord fm ll func.: "+max_loc_ll(0)+"; max. y_coord fm ll func.: "+max_loc_ll(1))
>
> ; Old latlon_to_ij function
> min_loc_latlon = wrf_user_latlon_to_ij(f1,xLat_min,xLong_min)
> max_loc_latlon = wrf_user_latlon_to_ij(f1,xLat_max,xLong_max)
>
>
> print("min. x-coord fm latlon func.: "+min_loc_latlon(1)+"; min. y_coord fm latlon func.: "+min_loc_latlon(0))
> print("max. x-coord fm latlon func.: "+max_loc_latlon(1)+"; max. y_coord fm latlon func.: "+max_loc_latlon(0))
>
>
> end
> ;;;
>
> Output from wrf_user_ll_to_ij
> min. x-coord fm ll func.: -16; min. y_coord fm ll func.: 0
> max. x-coord fm ll func.: 651; max. y_coord fm ll func.: 657
> Output from wrf_user_latlon_to_ij
> min. x-coord fm latlon func.: 0; min. y_coord fm latlon func.: 0
> max. x-coord fm latlon func.: 650; max. y_coord fm latlon func.: 650
> ;----------------------------------------------------------
>
>
>
> I am just wondering if there is some bug in this function (wrf_user_ll_to_ij).
>
> Cheers,
> ----
> Basit A. Khan, Ph.D.
> Postdoctoral Research Fellow
> Division of Physical Sciences & Engineering
> Office# 3204, Level 3, Building 1,
> King Abdullah University of Science & Technology
> 4700 King Abdullah Blvd, Box 2753, Thuwal 23955 –6900,
> Kingdom of Saudi Arabia.
>
> Office: +966(0)2 808 0276, Mobile: +966(0)5 0860 3617
> E-mail: basitali.khan@kaust.edu.sa
> Skype name: basit.a.khan
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Received on Tue Jun 12 09:55:11 2012

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