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Groups > comp.graphics.apps.gnuplot > #3912

Re: Missing points in multi line plot not being omitted

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On 10/03/2018 09:57 am, Jörg Buchholz wrote:
> On 10.03.2018 08:18, Ethan A Merritt wrote:
>> Jörg Buchholz wrote:
>>
>>> On 09.03.2018 19:48, Marius Schamschula wrote:
>>>
>>>>
>>>> FYI, I'm using version 5.2 patchlevel 2 under FreeBSD, so indeed
>>>> there should not be any quotes around the NaN
>>>>
>>>> Dealing with single points is easy: add a marker. My problem is
>>>> having lines where they shouldn't be.
>>>>
>>> I have compiled the 5.2.2 Version and it confuse me.
>>>
>>> set style data linespoints
>>> set datafile missing NaN
>>> plot '-' u 1:2
>>> input data ('e' ends) > 1 10
>>> input data ('e' ends) > 2 20
>>> input data ('e' ends) > 3 NaN
>>> input data ('e' ends) > 4 40
>>> input data ('e' ends) > 5 50
>>> input data ('e' ends) > e
>>>
>>> There is no gap in the output.
>>
>> Correct. There is no gap because the NaN point is treated as missing.
>>  From the docs under "help missing"
>>
>>     "invalid data causes a gap in a line drawn through sequential
>>      data points; missing data does not."
>>
>>
>>> unset datafile missing NaN
>>> plot '-' u 1:2
>>> input data ('e' ends) > 1 10
>>> input data ('e' ends) > 2 20
>>> input data ('e' ends) > 3 NaN
>>> input data ('e' ends) > 4 40
>>> input data ('e' ends) > 5 50
>>> input data ('e' ends) > e
>>>
>>> There is a gap between 2 - 4 in the output.
>>
>> Yes, because now the point is not "missing".  It is "invalid".
>>
>>> In the 5.2 Documentation there are some examples for the "set datafile
>>> missing option". Only the examples with "NaN" direct in the data gives
>>> a gap.
>>
>> Correct.
>>
>>> So can you put a "NaN" into your data?
>>>
>>> IMHO the 5.0 Version works nicer, or more than I expected. Or is it a
>>> bug?
>>
>>> Jörg
>>
>> Perhaps a misunderstanding.   Let me try re-phrasing...
>>
>> "Missing" data acts as if no entry at that x coordinate was present
>> in the data file at all, so it has no effect on the line being drawn.
>>
>> A gap in the line indicates that data at that x coordinate was present,
>> but invalid.
>>
>> The special command "set datafile missing NaN" tells the program
>> to treat invalid data as if it were missing (no gap).
>>
>> 	Ethan
>>
> Thanks for your explanation. So it was a misunderstanding. But the
> behave from gnuplot 5.0 is nice and easy to handle.
> 
> So for gnuplot 5.2 the only solution is something like "sed -i
> 's/?/NaN/g' datafile.dat" before plotting the data or in a pipe?
> 
> Jörg
> 

Or use "set datafile missing ?" (or "set datafile missing '?'") ??

 From the manual: There is no default character for missing, but in many 
cases any non-parsible string of characters found where a numerical 
value is expected will be treated as missing data.

So will a "?" in the data be treated as missing, even without the "set 
datafile missing" line. plot '-' using 1:($2) suggests it will.




-- 

Chris Elvidge, England

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Thread

Missing points in multi line plot not being omitted Marius Schamschula <mschamschula@gmail.com> - 2018-03-07 10:33 -0800
  Re: Missing points in multi line plot not being omitted Jörg Buchholz <bookwood4new@freenet.de> - 2018-03-08 11:39 +0100
    Re: Missing points in multi line plot not being omitted Marius Schamschula <mschamschula@gmail.com> - 2018-03-08 06:35 -0800
      Re: Missing points in multi line plot not being omitted Chris Elvidge <chris@mshome.net> - 2018-03-08 16:24 +0000
      Re: Missing points in multi line plot not being omitted Jörg Buchholz <bookwood4new@freenet.de> - 2018-03-08 20:10 +0100
        Re: Missing points in multi line plot not being omitted Ethan Merritt <sfeam@users.sf.net> - 2018-03-08 19:54 +0000
        Re: Missing points in multi line plot not being omitted Chris Elvidge <chris@mshome.net> - 2018-03-08 20:40 +0000
  Re: Missing points in multi line plot not being omitted Marius Schamschula <mschamschula@gmail.com> - 2018-03-09 10:48 -0800
    Re: Missing points in multi line plot not being omitted Jörg Buchholz <bookwood4new@freenet.de> - 2018-03-09 21:09 +0100
      Re: Missing points in multi line plot not being omitted Ethan A Merritt <EAMerritt@gmail.com> - 2018-03-09 23:18 -0800
        Re: Missing points in multi line plot not being omitted Jörg Buchholz <bookwood4new@freenet.de> - 2018-03-10 10:57 +0100
          Re: Missing points in multi line plot not being omitted Chris Elvidge <chris@mshome.net> - 2018-03-10 11:09 +0000
            Re: Missing points in multi line plot not being omitted Jörg Buchholz <bookwood4new@freenet.de> - 2018-03-10 17:40 +0100
              Re: Missing points in multi line plot not being omitted Chris Elvidge <chris@mshome.net> - 2018-03-10 17:01 +0000
                Re: Missing points in multi line plot not being omitted Jörg Buchholz <bookwood4new@freenet.de> - 2018-03-11 09:47 +0100
                Re: Missing points in multi line plot not being omitted Chris Elvidge <chris@mshome.net> - 2018-03-11 10:41 +0000

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