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Re: linfit with string time array (x) [message #63432 is a reply to message #63431]

Tue, 11 November 2008 00:28

julia.walterspiel
Messages: 35
Registered: July 2008

Member

On 11 Nov., 06:45, l...@lbnc.de wrote:
> On 10 Nov, 16:43, Reimar Bauer <R.Ba...@fz-juelich.de> wrote:
>
>
>
>> if the numbers are written in a time format it is better to show an
>> example. Those need to be converted into a number. I would suggest to
>> use julian seconds (seconds since 2000-01-01 00:00:00 UTC)
>
> But why?! Why go through the bother when IDL has JULDAY and CALDAT?
> With the LABEL_DATE function you get nice annotations of axes and you
> don't need to worry about whether the routines you download somewhere
> of the web are actually right.
>
> To answer the original question, as Reimar alrady said, you need to
> convert the strings to some sort of numeric value, for example julian
> day. For that you need to parse the year, month, day, hour, minute,
> second from your string and pass the to, for example, JULDAY. The IDL
> documentation knows more about how to use JULDAY and LABEL_DATE.
>
> Cheers
> Lasse Clausen

hi guys
well I thought I had already converted the string to some sort of
numeric value but I guess it was just the problem of doing what Reimar
said (new = double(date)). here's how I extracted my date from the
file name:

date = STRMID(filename_short, 10,7)
year = Fix(StrMid(StrTrim(date,2), 0, 4))
dayofyear = Fix(StrMid(StrTrim(date,2), 4, 3))
CALDAT, JULDAY(1, dayofyear, year), month, day
date = julday(month, day, year)

--> then my date of data looks like this: 2451605

That's what confuses me; a number that is obviously considered a
string. so I guess IDL doesn't take the "number" but rather what is
behind the calculation (julday) and refers to that as a string? Or am
I misunderstanding something?
It works fine when I convert it to double, so thanks for that input. I

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[Message index]

		Re: linfit with string time array (x) By: David Fanning on Tue, 11 November 2008 05:39
		Re: linfit with string time array (x) By: David Fanning on Tue, 11 November 2008 05:36
		Re: linfit with string time array (x) By: R.Bauer on Tue, 11 November 2008 00:51
		Re: linfit with string time array (x) By: R.Bauer on Tue, 11 November 2008 00:38
		Re: linfit with string time array (x) By: julia.walterspiel on Tue, 11 November 2008 00:28
		Re: linfit with string time array (x) By: lbnc on Mon, 10 November 2008 21:45
		Re: linfit with string time array (x) By: R.Bauer on Mon, 10 November 2008 08:43
		Re: linfit with string time array (x) By: Michael Galloy on Tue, 11 November 2008 12:31

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