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Groups > comp.graphics.apps.gnuplot > #1457

Re: plotting data directly from an Internet link?

From sfeam <sfeam@users.sourceforge.net>
Newsgroups comp.graphics.apps.gnuplot
Subject Re: plotting data directly from an Internet link?
Followup-To comp.graphics.apps.gnuplot
Date 2012-10-30 22:54 -0700
Organization gnuplot development team
Message-ID <k6qef5$2ac$1@dont-email.me> (permalink)
References <cf7a8cca-4187-432d-84f9-1c6df0bf7871@googlegroups.com> <k6nbur$pep$1@dont-email.me> <9ceb5771-afd5-4a4e-b90e-00f8f283626a@googlegroups.com>

Followups directed to: comp.graphics.apps.gnuplot

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TonyG wrote:

> On Monday, October 29, 2012 9:53:32 PM UTC-4, sfeam wrote:
>> TonyG wrote:
>> 
>> 
>> 
>> > Is it possible to use an Internet link to some column-formatted
>> > data
>> 
>> > as the data source for the 'file' part of the 'plot' command?
>> 
>> > 
>> 
>> > A good example would be plotting selected columns from
>> 
>> > http://www.ndbc.noaa.gov/data/5day2/44013_5day.txt
>> 
>> > 
>> 
>> > BTW, since I use a WinXP OS, I doubt I could use the pop(x) method
>> > as
>> 
>> > described in the Help file, e.g.,
>> 
>> > 
>> 
>> > pop(x) = 103*exp(-x/10)
>> 
>> > plot "< awk '{print $1-1965, $2}' population.dat", pop(x)
>> 
>> 
>> 
>> 
>> 
>> You say "I doubt I could use....".
>> 
>> But have you actually tried it?
> 
> Now I have... ;-)
> 
>> 
>> So long as the gnuplot executable supports pipes, you should
>> 
>> be OK.
> 
> Yes, I'm using gnuplot_pipes as my default executable.  (BTW, why are
> there two versions if gnuplot_pipes has more capabilities; is there
> something missing in it in comparison to std. gnuplot?)

Good question.  I'm not a Windows user, but my understanding is
that the distinction went away in version 4.6 because all the 
functionality of both the previous versions is in the single
executable gnuplot.exe


>> At least under linux one answer is
>> 
>>   plot "< GET http://www.ndbc.noaa.gov/data/5day2/44013_5day.txt"
>> 
>> 
>> 
>> where GET is a widely-distributed perl script roughly equivalent
>> 
>> to wget.  If you prefer wget, then
>> 
>>   plot "< wget -O -
>>   http://www.ndbc.noaa.gov/data/5day2/44013_5day.txt"
> 
> Thanks; wget works, and downloads and displays the data when used from
> the command line.  However, it bombs out when used inside gnuplot:
> 
> gnuplot> plot "< wget -O -
> http://www.ndbc.noaa.gov/data/5day2/44013_5day.txt" using ($13) w lp
>          warning: Skipping unreadable file "< wget -O -
>          http://www.ndbc.noaa.gov/data/5day2/44013_5day.txt" No data
>          in plot
> 
> The input file has a two-row header:
> 
> #YY  MM DD hh mm WDIR WSPD GST  WVHT   DPD   APD MWD   PRES  ATMP 
> #WTMP  DEWP  VIS PTDY  TIDE
> #yr  mo dy hr mn degT m/s  m/s     m   sec   sec degT   hPa  degC 
> #degC  degC  nmi  hPa    ft
> 2012 10 30 14 50 120  6.0  8.0   3.1    11   7.2 104 1001.2  14.0 
> 12.4  12.5   MM +2.8    MM
> 2012 10 30 13 50 130  8.0  9.0   3.3    10   7.6  95 1000.4  14.1 
> 12.4  12.6   MM +2.6    MM
> 
> but in my experience gnuplot handles such cases easily...  I have
> tried various changes, but to no avail--I'm stuck.

I don't know.  That command works for me under linux.
I get this output:

gnuplot> set term dumb
gnuplot> plot "< wget -O - http://www.ndbc.noaa.gov/data/5day2/44013_5day.txt" using ($13) w lp
--2012-10-30 22:53:12--  http://www.ndbc.noaa.gov/data/5day2/44013_5day.txt
Resolving www.ndbc.noaa.gov (www.ndbc.noaa.gov)... 140.90.238.27
Connecting to www.ndbc.noaa.gov (www.ndbc.noaa.gov)|140.90.238.27|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 11468 (11K) [text/plain]
Saving to: “STDOUT”

100%[============================================>] 11,468      48.3K/s   in 0.2s    

2012-10-30 22:53:13 (48.3 KB/s) - written to stdout [11468/11468]

  1025 ++---------+-----------+----------+----------+-----------+----AA-AAA+
       +          +           +          +          +           +   AAAAA+ +
  1020 ++                                                    AAAAAAA      ++
       |                                               AAAAAAA             |
       |                                       AAAAAAAAA                   |
  1015 ++                                AAAAAAA                          ++
       |                             AA A                                  |
  1010 ++                           A  A                                  ++
       |                           A                                       |
       |                         AA                                        |
  1005 ++                       A                                         ++
       | A AAAAA              AA                                           |
  1000 AA A    AA            AA                                           ++
       |         AA          A                                             |
   995 ++         AA        A                                             ++
       |            AA     A                                               |
       |              A A  A                                               |
   990 ++              A AA                                               ++
       +          +           +          +          +           +          +
   985 ++---------+-----------+----------+----------+-----------+---------++
       0          20          40         60         80         100        120



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Thread

plotting data directly from an Internet link? TonyG <tgozdz@gmail.com> - 2012-10-29 10:15 -0700
  Re: plotting data directly from an Internet link? James <jjpuzzles@wowway.com> - 2012-10-29 13:00 -0700
    Re: plotting data directly from an Internet link? TonyG <tgozdz@gmail.com> - 2012-10-29 15:19 -0700
  Re: plotting data directly from an Internet link? sfeam <sfeam@users.sourceforge.net> - 2012-10-29 18:53 -0700
    Re: plotting data directly from an Internet link? TonyG <tgozdz@gmail.com> - 2012-10-30 08:56 -0700
      Re: plotting data directly from an Internet link? sfeam <sfeam@users.sourceforge.net> - 2012-10-30 22:54 -0700
        Re: plotting data directly from an Internet link? TonyG <tgozdz@gmail.com> - 2012-10-31 06:44 -0700

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