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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
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