Re: [ferret_users] stiff modulo argument of x-axis

[Martin Schmidt <martin.schmidt@xxxxxxxxxxxxxxxxx>]

Hi Karl,

thanks for the suggestion with

cancel mode upcase

I was not aware of this option.  It helps to prevent that the new axis is written! This solves the problem.

Why I want to cancel the module attribute? My region covers only 15 degrees and some 
subsequent tools look if the data are modulo or not. So I simply want to have correct attributes.

Many thanks for your help,
Martin 


Karl Smith wrote:
> Hi Martin,
>
> Does 'cancel mode upcase' solve your original problem of new axes with
> uppercase names?
>
> It also seems surprising to me that you don't want your longitudes to
> have a modulo of 360 degrees.
> Not sure why your 'cancel axis/modulo' call isn't working for you.
> You might want to 'set mode verify' to make sure your command is doing
> what you think it is doing.
>
> yes? def axis /X=5E:35E:1 /modulo=75 xax
> yes? sh axis xax
>  name       axis              # pts   start                end
>  XAX       LONGITUDE           31mr   5E                   35E
>    Axis span (to cell edges) = 31 (modulo length = 75)
> yes? can axis /modulo xax
> yes? sh axis xax
>  name       axis              # pts   start                end
>  XAX       LONGITUDE           31 r   5E                   35E
>    Axis span (to cell edges) = 31
>
> Karl
>
>
> On Fri, Apr 20, 2012 at 3:06 AM, Martin Schmidt
> <martin.schmidt@xxxxxxxxxxxxxxxxx> wrote:
>   
>> Hi,
>> I have a given regional data set stored in a netcdf-file topo.dta.nc. The
>> axes are lat/lon, no modulo attribute is defined.
>>
>> I derive a new variable from a variable in the data set and hope to have it
>> defined at the same axis. For example:
>>
>> let htp_closed = if i[gx=htp] eq 1 the 1/0 else htp
>>
>> My choice would be to append the variable to the existing file. However, I
>> cannot force ferret to use the same axis, xt_i, yt_j.
>> Instead two new capital XT_I, YT_J show up which are stored separately and
>> have new attributes different from
>> the original axes. This confuses a program to read the data later.
>>
>> Putting the new variable onto the old grid using @asn does not help either.
>>
>> So I try to write to a new file;
>>
>> save/clobber/file=my_new_file.nc htp_closed
>>
>> Doing so, I get the modulo attribut set to 360 in the x- axis.
>>
>> can axis/modulo `htp_closed,return=xaxis`
>>
>> does not remove the modulo attribute. Also using the explicit axis name does
>> not help.
>>
>> How can I get rid of the wrong modulo attribute in the frame of ferret?
>>
>> Would it be possible to change the behaviour of ferret in future releases in
>> such a way,
>> that a modulo attribute must be set if it is required and correct, or is
>> inherited from other axis that are modulo?
>>
>> Dealing with regional data the automatic choice of ferret is always wrong
>> and it reveals as very stiff to
>> produce correct data.
>>
>> Many thanks,
>> Martin Schmidt
>>
>>
>>
>>
>>     
>
>
>