[R] bwplot puts the bars in the wrong place

[David Winsemius]

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 was attached in my first effort at posting but was too big for  
the list-server.

>
>
> 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
>
-- 

David Winsemius, MD
West Hartford, CT