RE: Negative longitudes

["McCann, Mike" <mccann@xxxxxxxxx>]

Steve,

Thanks for the answer.  I need to have the axis modulo, otherwise
the data set does not work in LAS.  I think my best avenue for now,
until 5.3 is available, is to add 360 to my longitude axes.  What 
is the best way to do this dynamically inside a GO script?   

-Mike 

> -----Original Message-----
> From: Steve Hankin [mailto:hankin@pmel.noaa.gov]
> Sent: Tuesday, May 29, 2001 3:16 PM
> To: McCann, Mike
> Cc: ferret_users@ferret.wrc.noaa.gov
> Subject: Re: Negative longitudes
> 
> 
> Hi Mike,
> 
> The problem that you report is due to a bug in V5.22.  It has 
> been fixed in
> V5.3.
> 
> As a work-around for the problem in V5.22 try this:
>    yes? def axis/x/units=deg/edges x1={-123,-122}
> 
> You can peek into the internals of the bug by noting the 
> erroneous output of
> SHOW AXIS/X (see the messed up "BOX_SIZE":
> 
>  yes? def axis/x/units=deg/modulo x1={-122.5}
>  yes? show axis/x x1
>   name       axis       # pts   start                end
>   X1        LONGITUDE     1mr   122.5W(-122.5)    122.5W(-122.5)
>            I     X                 BOX_SIZE
>            1>  122.5W(-122.5)        -61.25
> 
>     - steve
> 
> -------
> 
> P.S. Do you really want "/modulo" for a single point axis? If 
> so, then you
> probably would want to make sure the axis span is 360 degrees as in
>  yes? def axis/x/units=deg/edg/mod x1={`-122.5-180`,`-122.5+180`}
>  yes? show axis/i=1:3 x1
>   name       axis      # pts   start            end
>   X1        LONGITUDE    1mi   122.5W(-122.5)   122.5W(-122.5)
> 
>            I     X                 BOX_SIZE
>            1>  122.5W(-122.5)        360
>            2>  122.5W                360
>            3>  122.5W(597.5)         360
> 
> =======================================================
> 
> "McCann, Mike" wrote:
> 
> > Hi Ferreters,
> >
> > I'm trying to rename an axis and have encountered a strange thing
> > that can be boiled down to this little example:
> >
> >   def axis/x/units=deg/modulo x1={-122.5}               ! 
> Negative Long
> >   let v1=x[gx=x1]
> >   def axis/x/units=deg/modulo/name=x2 v1
> >
> > gives the error:
> >
> >   **ERROR: illegal limits: V1 is not in the range X=122.5W(-122.5)
> >           Axis extremes are X=122.5W(-122.5)
> >
> > whereas
> >
> >   def axis/x/units=deg/modulo x1={122.5}                ! 
> Positive Long
> >   let v1=x[gx=x1]
> >   def axis/x/units=deg/modulo/name=x2 v1
> >
> > gives no error.
> >
> > I've read
> > http://ferret.wrc.noaa.gov/Ferret/Mail_Archives/fu_97/msg00031.html
> > but would prefer not having to add 360 to my longitudes.
> >
> > Is the above example normal behavior?  Is there a simpler way to
> > give an axis a new name?
> >
> > Thanks in advance,
> > Mike
> >
> > --
> > Mike McCann   (mccann@mbari.org)
> > Monterey Bay Aquarium Research Institute
> > 7700 Sandholdt Road
> > Moss Landing, CA 95039-9644
> > Voice: (831) 775-1769   Fax: (831) 775-1646 
> http://www.mbari.org/rd/iag.htm
> 
> --
> 
>                 |  NOAA/PMEL               |  ph. (206) 526-6080
> Steve Hankin    |  7600 Sand Point Way NE  |  FAX (206) 526-6744
>                 |  Seattle, WA 98115-0070  |  hankin@pmel.noaa.gov
> 
>