Re: Error from using "where" function

Hi Jingmin,

As Dennis indicated, your syntax is incorrect. You've provided the
conditional expression, but you have not told the function what to
do when the condition is true, and what to do when the condition is
false.

Please carefully study the documentation for the where function,
as it provides several examples that nicely illustrate proper use
of that function.

http://www.ncl.ucar.edu/Document/Functions/Built-in/where.shtml

Good luck!

Daran

Daran Rife
Head of Mesoscale Modeling
GL Garrad Hassan

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--
[1] The syntax you used is incorrect. Further, the
     shapes of the arrays in your statement are inconsistent.
[2] If the sst array has one-dimensional coordinate variables, use
     sst(:,{latS:latN},{lonW:lonE}) = 0
If you are new to NCL, please read the mini-language manual at
    http://www.ncl.ucar.edu/Document/Manuals/
Good Luck
On 4/11/12 1:51 AM, Jingmin Li wrote:
> Hello, Here is me again.
>
> My code below at the line with where function should be :
>
> sst= where( (sst@lat.ge.latS .and. sst@lat.le.latN .and. \
>                 sst@lon.ge.lonW .and. sst@lon.le.lonE),0,sst)
>
> Sorry for my mistake. Please have a look what is the problem!
> Thanks.
> Jingmin
>
> ----- Forwarded message from jingmin.li@uni-tuebingen.de -----
>       Date: Wed, 11 Apr 2012 09:26:00 +0200
>       From: Jingmin Li<jingmin.li@uni-tuebingen.de>
>    Subject: Error from using "where" function
>         To: ncl-talk@ucar.edu
>
> Hello,
>
> I have a 3-dimensional array coordinate arrays time*lon*lat. I want to
> set all values outside a domain region to 0.
>
> I copied one example of "where" function from NCL home. But I got
> always error message like:
> --------------------
> fatal:And: Dimension size, for dimension number 0, of operands does
> not match, can't continue)
> fatal:where: condition variable (parameter 1) dimension mismatch with
> parameter 2.
> -----------------------
>
> Does anyone know what is the problem? Thanks!
> Jingmin
>
> Here is my code:
> ---------------------
> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"
>
> begin
>
>      data_dir  = "/home/jingmin/echam_plot"
>      cdf_file = addfile(data_dir + "/T21_amip2sst_2000_copy.nc","r")
>
>      sst = cdf_file->sst    ; files to local variables.
>      sst@time = cdf_file->time
>      sst@lat  = cdf_file->lat        ; Create coordinate variables
>      sst@lon  = cdf_file->lon        ; for sst and store the sizes
>
>      latS  =  30.00
>      latN  =  40.00
>      lonW  =  70.00
>      lonE  =  140.00
>
>      sst= where( (sst@lat.ge.latS .and. sst@lat.le.latN .and. \
>                  sst@lon.ge.lonW .and. sst@lonE),0,sst)
>      end
> ----------------------------------
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