# [ncl-talk] Remove SST data for specific area

Dinuka Silva dinu.kera at gmail.com
Thu Aug 31 02:18:21 MDT 2017

```Thank you very much for your help. I could do that.

Dinuka

On Thu, Aug 31, 2017 at 12:29 AM, Mary Haley <haley at ucar.edu> wrote:

> Quick FYI: in general you want to avoid "do" loops, as they can be slow in
> scripting languages.
>
> Using"conform_dims" as Guido suggested would be faster:
>
> dims2d = (/dimsizes(lat), dimsizes(lon)/)
> lat2d  = conform_dims(dims2d,lat,0)
> lon2d  = conform_dims(dims2d,lon,1)
>
> http://www.ncl.ucar.edu/Document/Functions/Built-in/conform_dims.shtml
>
> --Mary
>
>
>
> On Wed, Aug 30, 2017 at 2:34 AM, Guido Cioni <guidocioni at gmail.com> wrote:
>
>> One way to go would be to use the 1-D array anyway by doing a smart
>> conform. Otherwise you can create 2-D "dummy" variables using these
>> functions:
>>
>> undef("create_lon2d")
>> function create_lon2d(lat[*]:numeric, lon[*]:numeric)
>> local x, i
>> begin
>>   x = new((/dimsizes(lat),dimsizes(lon)/),typeof(lat))
>>   do i=0,dimsizes(lat)-1
>>     x(i,:) = lon
>>   end do
>>   return(x)
>> end
>>
>> undef("create_lat2d")
>> function create_lat2d(lat[*]:numeric, lon[*]:numeric)
>> local y, i
>> begin
>>   y = new((/dimsizes(lat),dimsizes(lon)/),typeof(lat))
>>   do i=0,dimsizes(lon)-1
>>     y(:,i) = lat
>>   end do
>>   return(y)
>> end
>>
>>     lat2d = create_lat2d(lat,lon)
>>     lon2d = create_lon2d(lat,lon)
>>
>> On 30. Aug 2017, at 10:29, Dinuka Silva <dinu.kera at gmail.com> wrote:
>>
>>
>> printVarSummary(x) is as follows.
>>
>>
>> Variable: x
>> Type: float
>> Total Size: 454377600 bytes
>>             113594400 values
>> Number of Dimensions: 3
>> Dimensions and sizes:   [time | 1753] x [latitude | 180] x [longitude |
>> 360]
>> Coordinates:
>>             time: [15.49999..53340.5]
>>             latitude: [89.5..-89.5]
>>             longitude: [-179.5..179.5]
>> Number Of Attributes: 8
>>   lon2d :       <ARRAY of 360 elements>
>>   lat2d :       <ARRAY of 180 elements>
>>   _FillValue :  -1e+30
>>   standard_name :       sea_surface_temperature
>>   long_name :   sst
>>   units :       C
>>   cell_methods :        time: lat: lon: mean
>>   missing_value :       -1e+30
>> fatal:And: Dimension size, for dimension number 0, of operands does not
>> match, can't continue
>>
>> It looks like "latitude" and "longitude" are 1D arrays . How can I make
>> them to be 2D arrays.
>>
>> Dinuka.
>>
>>
>> On Wed, Aug 30, 2017 at 4:04 PM, Guido Cioni <guidocioni at gmail.com>
>> wrote:
>>
>>> Dinuka,
>>> don’t start new topic if the problem is always the same. People will get
>>> confused when they search for answers.
>>>
>>> Did you check that your latitude and longitude are 2-D arrays?
>>> The error is exactly telling you where the problem is.
>>>
>>>
>>> Il giorno 30 ago 2017, alle ore 07:30, Dinuka Silva <dinu.kera at gmail.com>
>>> ha scritto:
>>>
>>> Hi all,
>>>
>>> I want to remove SST data of one box ({03N - 12N}, {90E- 140E}) and then
>>> find the correlation between remaining SST data and rainfall index. I want
>>> to know how can I remove the SST data of that box. SST data has 3
>>> dimensions. I used mask function but I got error message.
>>>
>>> x =  fin2->sst(:,:,:)
>>>
>>>     x at lat2d = fin2->latitude
>>>     x at lon2d = fin2->longitude
>>>
>>>
>>>     latMin  = 03
>>>     latMax  = 12
>>>     lonMin  = 90
>>>     lonMax  = 140
>>>
>>>   x   = mask (x, conform(x, (x at lat2d.ge.latMin .and.x at lat2d.le.latMax .
>>> and.x at lon2d.ge.lonMin .and.x at lon2d.le.lonMax), (/1,2/)), True)
>>> printVarSummary(x)
>>>
>>>
>>> The error message : Dimension size, for dimension number 0, of operands
>>> does not match, can't continue
>>>
>>>
>>> Dinuka
>>>
>>>
>>>
>>> www.avast.com
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>>>
>>>
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>>
>>
>> Guido Cioni
>> http://guidocioni.altervista.org
>>
>>
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>>
>
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