display global data

[Michael Fiorino]

Nakazawa-san, the best way to do that would be to
'set x 1 N points'

this forces to display the exact grid.  best /r Mike

Tetsuo Nakazawa wrote:
> Dear Jennifer-san,
>
>>>  My friend asked me the following questions, but I could not answer.
>>> I hope someone helps me.
>>>
>>>  Question:
>>>   There is a following ctl file. The data is global, starting from
>>> -179.75 with 0.5 deg resolution.
>>>   When the display command is issued, then GrADS says that the
>>> display area is set to like,
>>>
>>> LON set to 0 360
>>> LAT set to ....
>>> LEV set to ....
>>> Time ..........
>>>
>>>   The question is that the original ctl shows that the western
>>> boundary of the data is from -179.75,
>>> however, the display says GrADS changed the longitude, starting from
>>> 0. Do you know why?
>>>
>> When GrADS detects that a grid 'wraps' the globe, it sets the LON
>> dimension environment to be 0 to 360. If it doesn't wrap, it sets
>> the X dimension environment to be 1 to XSIZE. The test for whether
>> a grid wraps goes like this:
>> In your descriptor file you have: XDEF n linear v1 v2
>> temp =  (v1 + (n*v2) - 360)
>> if (fabs(temp-v1) <  0.01) then the grid wraps.
>> Non-linear X axes are never tested to see if they wrap.
>>
>
>  Thanks.
>
>  Sometimes one would like to plot globally as the data is stored.
> And also, one suspects
> that the data is wrong or GrADS is wrong if GrADS changes the
> starting longitude from 0 deg.
>
> ********************************************
> Tetsuo Nakazawa
>                       nakazawa at mri-jma.go.jp
> Typhoon Research Department
> Meteorological Research Institute
> Tel:  029-853-8671 Fax: 029-853-8735
> ********************************************