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

[Karl Smith <karl.smith@xxxxxxxx>]

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
>
>
>
>



-- 
Karl M. Smith, Ph.D.
JISAO Univ. Wash. and TMAP/PMEL NOAA
"The contents of this message are mine personally and do
not necessarily reflect any position of the Government
or the National Oceanic and Atmospheric Administration."