[Thread Prev][Thread Next][Index]

Re: log plots for a depth axis



Hi Brent,

Have you had a look at
    yes? go log_plot_demo

(can be located via the Unix-level command  ">Fgo log" or "log" in the Users
Guide index)

The log plotting is a bit "fussy". Here is an example:

     define axis/z zlog = exp(k[k=1:10])  ! some axis
     let fcn = k[gz=zlog]                 ! some function
     set view upper
     plot fcn
     set view lower
     ppl axtype 1,2
     plot/k=1:10/vlimits=0:5 fcn
     ppl axtype 1,1                       ! restore normal plotting

The resulting plot  is attached (GIF).

I do not know of a way to invert the vertical log axis (high pressure at the
bottom). We hope to have that feature in V5.3.

    - steve

===================================

Brent A McDaniel wrote:

> Hi Ferreters,
>
> I'm trying to make plots for atmospheric data where the vertical
> coordinate is pressure.  The vertical axis is from 1000mb up to 10mb.  The
> levels are not equally spaced.  What I want is a plot with pressure on the
> y-axis, but plotted logarithmically.  Hopefully you understand what I mean
> as this is the a pretty way to do these types of plots.
> I'll try my hand at crude ascii art.
>
> 10
> .
> .
> .
> .
>
> 100 |
>     |
>     |
>     |
> 200 | <-- y-axis is spaced log
>     |
>     |
> 300 |
>     |
>     |
> 500 |
>     |
> 700 |
>     |
> 850 |
> 1000|
>     ---------------------------------------------
>                         x-axis is normal
>
> After reading the FAQ and the mailing list archives, I started by defining
> a new z-axis:
> yes? define axis/from/name=test/z log(z[gz=level])
> and plotting things by:
> yes? contour temp[gz=test@asn]
>
> This produces a log plot but the y-axis is inverted (which makes sense as
> the logs of the highest pressure levels will be the smallest.  Also, the
> y-axis doesn't have the original pressure levels on it but the new values
> (1-3 from log10 to log1000).  The inversion was fixed by adding the /depth
> qualifier to the define axis statement. (now I'm using:
> define axis/from/name=test/z/depth log(z[gz=level]) but I still have the
> problem of the y-labels not being the original 1000-10 values.
>
> Does anyone have a decent workaround for this? I've got a meeting next
> week and plots that need to be done. *yikes!*
>
> Thanks as always.
>
> - Brent
>
> --
> Brent A. McDaniel
>
> Dept of Earth and Atmospheric Sciences
> Georgia Institute of Technology
> Atlanta, Ga.  USA

--
Steve Hankin
NOAA/PMEL, 7600 Sand Point Way NE, Seattle, WA 98115-0070
ph. (206) 526-6080 -- FAX (206) 526-6744

GIF image


[Thread Prev][Thread Next][Index]

Dept of Commerce / NOAA / OAR / PMEL / TMAP

Contact Us | Privacy Policy | Disclaimer | Accessibility Statement