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Re: How to handle gaps in plot? [message #45118 is a reply to message #45113]

Thu, 11 August 2005 09:40

Paul Van Delst[1]
Messages: 1157
Registered: April 2002

Senior Member

caitouer wrote:
> Thanks for your quick reply. It is true that it is easy when you have
> filled the gap with some values. However, I am trying to figure out
> how to plot when you do not fill the gap. Here is an example:
>
> X (time):[1,2,3,5,6,7,10,11,12,19,20,21,22,23,24]
> ;Hourly data in one day. There are several gaps in the data
> ;array. You do not know when you will have gap nor
> ; how large the gap is. The actual data is not so regular and
> ;huge. So it is not practical to fill the data.
>
> Y (some values):
> [1.1,0.9,1.3,1.6,2.1,0.7,2.3,0.1,0.3,0.6,0.9,1.4,1.3,1.7,1.8 ]
> ; these are the measurements you take at above time.
>
> Then when you type:
> plot,x,y
> There will have lines between the intervals. However, these lines are
> meaningless.
>
> I just want know if we plot the valid intervals only without those
> extra lines.

Ahh... so you don't actually have invalid data in these gaps, just irregularly spaced data. The
simplest solution is to use the PSYM keyword to plot just symbols and no connecting lines at all
(since the lines between the regular, hourly data are also meaningless... at least depending on the
variabiliy of your data).

Another option would be to create a regularly spaced array of x-data (based on yout x(time) data),
copy in the y-data to a simialrly spaced array and fill the y-data gaps with !values.d_nan. E.g.

IDL> x=dindgen(20)
IDL> y=dindgen(20)
IDL> y[5:8]=!values.d_nan
IDL> plot, x, y

Insty-gap in the data plot.

paulv

--
Paul van Delst
CIMSS @ NOAA/NCEP/EMC

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[Message index]

		Re: How to handle gaps in plot? By: Craig Markwardt on Fri, 12 August 2005 21:16
		Re: How to handle gaps in plot? By: peter.albert@gmx.de on Thu, 11 August 2005 23:13
		Re: How to handle gaps in plot? By: Paul Van Delst[1] on Thu, 11 August 2005 09:40
		Re: How to handle gaps in plot? By: caitouer on Thu, 11 August 2005 09:06
		Re: How to handle gaps in plot? By: Paul Van Delst[1] on Thu, 11 August 2005 08:14
		Re: How to handle gaps in plot? By: caitouer on Mon, 22 August 2005 12:20

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