[R] bwplot puts the bars in the wrong place

Sat Apr 17 18:09:01 CEST 2010

On Apr 17, 2010, at 11:01 AM, James Rome wrote:

> Ah,
>
> Well, I thought I put up just the data needed. Sorry, was wrong file.
> And yes I am still climbing up the very steep learning curve hill. I
> attach a better data set. If it gets stripped, it is at
> http://dl.dropbox.com/u/537118/gdf.txt
>
> 1. I put the gdf$tt~gdf$OnHour because in the rest of my code, there  
> are
> other (previous and bigger) incarnations of this data frame with the
> same names. Or does the call automatically assume that the variable
> names are from the frame in the data= statement? How am I to know?

Yes, R does "assume" such. Formula methods are a rather fundamental  
concept in R. Your readings should have exposed you to that concept.

> 2. The plot you enclosed is still not correct. The 0 time things are
> plotted at 1. And I believe that there are no data at 3 am. That is  
> why
> I asked the question, and I think this is also the key to the problem.

Had that been clearly stated earlier, I might have realized my  
solutions were not complete.

> 3. I did create factors as Jun suggested, and they are in OnHFact. But
> using OnHFact instead of OnHour also gives the wrong plot.

I'm assuming that Ehlers' posting of a few minutes ago was the correct  
solution, i.e, that you needed a more complete specification of levels  
of the factor?

>
> The only thing that put the correct data on the correct hours was to
> call xyplot instead of bwplot, with panel.bwplot in the panel  
> function.
>
> Sorry for being so dense,  but I really find it much harder to read R
> documentation, than say, Java documentation. And I have 10 R books
> including R Graphics, which did not shed light on this issue either.
>
> Thanks for the help,
> Jim Rome
>
> On 4/17/10 9:52 AM, David Winsemius wrote:
>> After unzipping that file, http://dl.dropbox.com/u/537118/gdf.zip , I
>> got a structure object that took what seemed to be an inordinately
>> long time to eval-parse wehn assigned to gdf,  but it did eventually
>> produce:
>>
>>> str(gdf)
>> 'data.frame':    2656 obs. of  21 variables:
>> $ OnDate        :Class 'Date'  num [1:2656] 14222 14221 14334 14424
>> 14519 ...
>> $ FltOrigDt     : chr  "12/9/2008" "12/8/2008" "3/31/2009"
>> "6/29/2009" ...
>> $ MkdCrrCd      : chr  "DL" "DL" "DL" "DL" ...
>> $ MkdFltNbr     : int  742 1517 1517 1517 1517 1699 1065 1777 1777
>> 1777 ...
>> $ DprtTrpnStnCd : chr  "DEN" "JAX" "JAX" "JAX" ...
>> $ ArrTrpnStnCd  : chr  "ATL" "ATL" "ATL" "ATL" ...
>> $ ActualOutLocal: POSIXct, format: "2008-12-09 01:04:00" "2008-12-08
>> 05:37:00" "2009-03-31 05:32:00" ...
>> $ ActualOffLocal: POSIXct, format: "2008-12-09 01:47:00" "2008-12-08
>> 06:11:00" "2009-03-31 05:43:00" ...
>> $ ActualOnLocal : POSIXct, format: "2008-12-09 06:10:00" "2008-12-08
>> 06:56:00" "2009-03-31 06:33:00" ...
>> $ ActualInLocal : POSIXct, format: "2008-12-09 06:18:00" "2008-12-08
>> 07:02:00" "2009-03-31 06:39:00" ...
>> $ ArrivalGate   : Factor w/ 100 levels "A01","A02","A03",..: 2 2 2 2
>> 2 2 2 2 2 2 ...
>> $ DepartureGate : chr  "C44" "A7" "A7" "A10" ...
>> $ Flight        : chr  "DAL742" "DAL1517" "DAL1517" "DAL1517" ...
>> $ OnHour        : chr  "6" "6" "6" "6" ...
>> $ OnDateTime    : POSIXct, format: "2008-12-09 06:10:00" "2008-12-08
>> 06:56:00" "2009-03-31 06:33:00" ...
>> $ Runway        : Factor w/ 10 levels "08L","08R","09L",..: 2 4 4 7 4
>> 7 8 8 1 7 ...
>> $ Delay         : int  15 8 NA NA NA NA NA NA NA NA ...
>> $ TaxiTime      :Class 'difftime'  atomic [1:2656] 480 360 360 240
>> 360 420 300 300 540 780 ...
>>  .. ..- attr(*, "units")= chr "secs"
>> $ passurdt      : num  0 0 0 0 1 0 0 0 0 -7 ...
>> $ OnHFact       : Ord.factor w/ 24 levels "0"<"1"<"2"<"3"<..: 7 7 7 7
>> 7 8 8 13 13 12 ...
>> $ tt            : num  8 6 6 4 6 7 5 5 9 13 ...
>>
>>
>>
>> On Apr 16, 2010, at 9:37 PM, James Rome wrote:
>>
>>> On 4/16/2010 8:27 PM, Jun Shen wrote:Jim,
>>>
>>> Try this,
>>>
>>> bwplot(tt~as.factor(OnHour),data=gdf,......)
>>>
>>> Jun Shen from Millipore
>>>
>>> I already tried using a factor, and the data set I enclosed had
>>> gdf$OnHFact which was already a factor. It gave the same wrong plot.
>>>
>>> What did work was to call xyplot instead of bwplot, and to use
>>> panel.bwplot in the panel function:
>>>
>>>       hrs = seq(0, 23, 1)
>>>      hrlabs = as.character(seq(0,23,1))
>>>       g = xyplot(gdf$tt~gdf$OnHour |gdf$Runway, data=gdf,
>>
>> This is a puzzling way to invoke xyplot and may have unforeseen
>> dangers. Generally when one uses a data argument to a plot function,
>> one does not also include that dataframe name in the formula terms on
>> either the LHS or the RHS.
>>
>>> ylab="Taxi
>>> time (min)", main=title, xlab="Hour of day",
>>>           xlim=c(-1, 24), scales=list(x = list(rot=90, cex=.6,
>>> alternating=c(3,3,3,3),
>>>           at=hrs, labels=hrlabs
>>>           )),
>>>           panel=function(x, ...) {
>>>               panel.grid(h = -1, v = 24)
>>>               panel.bwplot(x, horizontal=FALSE, col="black",...)
>>>
>>>           }
>>>       )
>>>       print(g)
>>
>> I took your initial code for a bwplot call and took out the  
>> extraneous
>> dataframe name in the formula terms and put in your axis code (with
>> more sensible formatting) and got what appears to be your desired  
>> plot:
>>
>> bwplot( tt~ OnHour |Runway, data=gdf,
>>         scales=list(x = list(rot=90, cex=.6,
>>                               alternating=c(3,3,3,3),
>>                               at=hrs, labels=hrlabs
>>                     )        ),
>>         horizontal=FALSE)
>>
>> Plot attached.
>>
>>>
>>>
>>> But I do not understand why this makes a difference. It has  
>>> something to
>>> do with the fact that there are no data for some of the hours.
>>
>> I have not been able to figure out what you meant by "bars in the
>> wrong place". You could have been more forthcoming about what you saw
>> as the problem for the Readers of the list. My guess is that it has
>> something to do with not following the specified conventions for
>> arguments to the bwplot formula method.
>>
>>
>>> The difference between the calls  is either a bug, or it should be  
>>> in
>>> the documentation somewhere obvious. I spent a week on this.
>>
>> To report a bug you need a lot more specifics about your system and
>> better efforts at isolation to minimal cases.
>>
>>>
>>> Thanks,
>>> Jim Rome
>>>
>>> Thanks,
>>> Jim Rome
>>>
> <gdf.txt>

David Winsemius, MD
West Hartford, CT