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From |
moleps islon <moleps2@gmail.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: AW: st: RE: Graphing time on the x axis |

Date |
Tue, 22 Dec 2009 13:40:51 +0100 |

Thank you Nick. This is indeed the case. I'll have another look at it when I get back from work. Maybe if I instead code the time according to date in addition I'd get the correct elapsed time ? ie I add another day to the measurements after midnight. M On Tue, Dec 22, 2009 at 12:48 PM, Nick Cox <n.j.cox@durham.ac.uk> wrote: > As I understand it, you have subtracted one date-time from another, but the result is not itself a date-time. It is an elapsed time, and Stata lacks any support specific to elapsed times. So, for example, 1 (elapsed) day and 2 (elapsed) days look identical in terms of clock time, as you already know. > > . di %tc_HH:MM:SS 24 * 60 * 60 * 1000 > 00:00:00 > > . di %tc_HH:MM:SS 48 * 60 * 60 * 1000 > 00:00:00 > > Conversely, the difference between 21 December 2009 and 22 December 2009 is not as indicated by > > . di %d mdy(12,22,2009) - mdy(12,21,2009) > 02jan1960 > > But just 1 day. > > In short, applying date-time formats to elapsed times at best tells only part of the story and at worst gives you nonsense. That shouldn't be a surprise when you think about it. > > For elapsed times, you need to create your own code (setting aside earlier user-written efforts best consigned to history). > > In essence, Stata carries no knowledge forward of how your variables were calculated. As I guessed earlier in the thread, you assigned a format that is no use for graphing, as it does not distinguish elapsed times except in terms of what a clock would show. > > I asked earlier for you to -summarize- the values of your variables, but I've not seen any results. From your graph it seems that the data fall into two distinct subsets, times less than 1 day and times more than 1 day. I can't suggest why that is, but only looking at your data closely can tell you if there is some error or this does in fact make sense. > > As I suggested earlier, it is likely that you need to create your own axis labels, using a conversion from milliseconds to hours. -mylabels- from SSC is there to help. > > Nick > n.j.cox@durham.ac.uk > > moleps islon > > The measurements have taken place at -clock-. However trying to twoway > graph with clock along the x axis resulted in the problem with > changing dates and jumps on the graph. I tried to cricumvent this by > subtracting clock with the first clock-value.. but as you see it > leaves me with the same problem. I´m sure there is someway around > this... > > > > .format x %9.0g > > . l x clock in 1/5 > > +------------------+ > | x clock | > |------------------| > 1. | 0 18:46:46 | > 2. | 18000 18:47:04 | > 3. | 30000 18:47:16 | > 4. | 36000 18:47:22 | > 5. | 66000 18:47:52 | > +------------------+ > > M > > > > > On Mon, Dec 21, 2009 at 9:58 PM, Martin Weiss <martin.weiss1@gmx.de> wrote: >> >> <> >> >> I am not sure why you - format x %td_HH:MM:SS- while I formatted - format x >> %tc_HH:MM:SS-. What happens when you >> >> *** >> format x %9.0g >> l in 1/5 >> *** >> >> >> HTH >> Martin >> >> >> -----Original Message----- >> From: owner-statalist@hsphsun2.harvard.edu >> [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of moleps >> Sent: Montag, 21. Dezember 2009 21:51 >> To: statalist@hsphsun2.harvard.edu >> Subject: Re: AW: st: RE: Graphing time on the x axis >> >> To me there doesnt seem to be any difference between the sets, but doing the >> following explains why the graph looks as it does. However I do not >> understand how this comes about or how I can rectify it... >> >> >> >> . list x in 1/5 >> >> +----------+ >> | x | >> |----------| >> 1. | 00:00:00 | >> 2. | 00:00:18 | >> 3. | 00:00:30 | >> 4. | 00:00:36 | >> 5. | 00:01:06 | >> +----------+ >> >> . sort x >> >> . list x in 1/5 >> >> +----------+ >> | x | >> |----------| >> 1. | 05:10:24 | >> 2. | 05:10:30 | >> 3. | 05:10:36 | >> 4. | 05:10:42 | >> 5. | 05:10:48 | >> +----------+ >> >> >> M >> >> >> >> On 21. des. 2009, at 21.18, Martin Weiss wrote: >> >>> >>> <> >>> >>> How is your dataset different from the one I am playing with? >>> >>> >>> ******* >>> clear* >>> set obs 1000 >>> set seed 10234 >>> >>> gen x=(_n-1)*6000 >>> >>> format x %tc_HH:MM:SS >>> >>> gen mean_amp =rnormal() >>> gen meanp =rnormal() >>> >>> gen byte c7=(runiform()<.2)+1 >>> >>> compress >>> >>> tw (line mean_amp x if c7==1) /* >>> */ (line mean_amp x if c7==2) /* >>> */ (line meanp x if c7==1) /* >>> */ (line meanp x if c7==2) >>> ******* >>> >>> >>> HTH >>> Martin >>> >>> -----Original Message----- >>> From: owner-statalist@hsphsun2.harvard.edu >>> [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of moleps >>> Sent: Montag, 21. Dezember 2009 20:32 >>> To: statalist@hsphsun2.harvard.edu >>> Subject: Re: AW: st: RE: Graphing time on the x axis >>> >>> picture of the graph >>> >>> http://www.flickr.com/photos/45805518@N04/?saved=1 >>> >>> commands >>> >>> >>> >>> >>> >>> . format x %td_HH:MM:SS >>> >>> . list x in 1/5 >>> >>> +----------+ >>> | x | >>> |----------| >>> 1. | 00:00:00 | >>> 2. | 00:00:18 | >>> 3. | 00:00:30 | >>> 4. | 00:00:36 | >>> 5. | 00:01:06 | >>> +----------+ >>> . tw (line mean_amp x if c7==1) (line mean_amp x if c7==2) (line meanp >> x >>> if c7==1) (line meanp x >>>> if c7==2) >>> >>> Regards, >>> >>> M >>> >>> >>> >>> On 21. des. 2009, at 19.57, Martin Weiss wrote: >>> >>>> >>>> <> >>>> >>>> >>>> You should probably reproduce the problem with a dataset shipped with >>> Stata. >>>> Is the time variable numeric or string? >>>> >>>> >>>> >>>> HTH >>>> Martin >>>> >>>> >>>> -----Ursprüngliche Nachricht----- >>>> Von: owner-statalist@hsphsun2.harvard.edu >>>> [mailto:owner-statalist@hsphsun2.harvard.edu] Im Auftrag von moleps >>>> Gesendet: Montag, 21. Dezember 2009 19:48 >>>> An: statalist@hsphsun2.harvard.edu >>>> Betreff: Re: st: RE: Graphing time on the x axis >>>> >>>> Maybe I was unclear in my description of the graph, but i dont think it >> is >>> a >>>> scale or label question. The problem is that given the coordinates >> (00:00, >>>> 2.3) (05:36,1.9) (07:20,3.1) (18:58,2.9) they are not graphed in that >>> order; >>>> Instead I have (07:20,3.1) (18:58,2.9) (00:00, 2.3) (05:36,1.9) ... >>>> >>>> Regards >>>> >>>> M >>>> >>>> >>>> On 21. des. 2009, at 13.45, Nick Cox wrote: >>>> >>>>> Clearly you need to specify your own. >>>>> >>>>> A convenience tool is -mylabels- from SSC. You just need to specify the >>>> conversion from Stata's underlying scale, presumably milliseconds, to >> your >>>> desired scale, which may be hours (you don't say what you want instead). >>> See >>>> the help for more. >>>>> >>>>> Nick >>>>> n.j.cox@durham.ac.uk >>>>> >>>>> moleps islon >>>>> >>>>> I´ve created a variable, time, for two measurements that both have >>>>> been subtracted from the starting time of the measuerement so that the >>>>> two start out with time 00:00:00 and I have measurements every 10 >>>>> sec. However after doing a twoway plot the starting point is not >>>>> 00:00:00. Instead I have these tick marks and values along the x >>>>> axis:: 07:20--12:53--18:58--00:00--05:36.... Any ideas? > > * > * For searches and help try: > * http://www.stata.com/help.cgi?search > * http://www.stata.com/support/statalist/faq > * http://www.ats.ucla.edu/stat/stata/ > * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**Follow-Ups**:**RE: AW: st: RE: Graphing time on the x axis***From:*"Nick Cox" <n.j.cox@durham.ac.uk>

**References**:**st: Graphing time on the x axis***From:*moleps islon <moleps2@gmail.com>

**st: RE: Graphing time on the x axis***From:*"Nick Cox" <n.j.cox@durham.ac.uk>

**Re: st: RE: Graphing time on the x axis***From:*moleps <moleps2@gmail.com>

**Re: AW: st: RE: Graphing time on the x axis***From:*moleps <moleps2@gmail.com>

**Re: AW: st: RE: Graphing time on the x axis***From:*moleps <moleps2@gmail.com>

**Re: AW: st: RE: Graphing time on the x axis***From:*moleps islon <moleps2@gmail.com>

**RE: AW: st: RE: Graphing time on the x axis***From:*"Nick Cox" <n.j.cox@durham.ac.uk>

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