[R] Colour filling in panel.bwplot from lattice

[Rainer Hurling]

Am 03.11.2010 12:52 (UTC+1) schrieb Deepayan Sarkar:
> On Wed, Nov 3, 2010 at 4:25 PM, Rainer Hurling<rhurlin at gwdg.de>  wrote:
>> Am 03.11.2010 10:23 (UTC+1) schrieb Deepayan Sarkar:
>>>
>>> On Wed, Nov 3, 2010 at 4:11 AM, Dennis Murphy<djmuser at gmail.com>    wrote:
>>>>
>>>> Hi:
>>>>
>>>> I don't know why, but it seems that in
>>>>
>>>> bwplot(voice.part ~ height, data = singer,
>>>> main = "NOT THE RIGHT ORDER OF COLOURS\n'yellow' 'blue' 'green' 'red'
>>>> 'pink' 'violet' 'brown' 'gold'",
>>>> fill=c("yellow","blue","green","red","pink","violet","brown","gold"))
>>>>
>>>> the assignment of colors is offset by 3:
>>>>
>>>> Levels: Bass 2 Bass 1 Tenor 2 Tenor 1 Alto 2 Alto 1 Soprano 2 Soprano 1
>>>> fillcol<- c("yellow","blue","green","red","pink","violet","brown","gold")
>>>>
>>>> In the above plot,
>>>>
>>>> yellow ->    Bass 2  (1)
>>>> blue ->    Tenor 1     (4)
>>>> green ->    Soprano 2  (7)
>>>> red ->    Bass 1 (10 mod 8 = 2)
>>>> pink ->    Alto 2 (13 mod 8 = 5)
>>>> etc.
>>>>
>>>> It's certainly curious.
>>>
>>> Curious indeed. It turns out that because of the way this was
>>> implemented, every 11th color was used, so you end up with the order
>>>
>>>> sel.cols<-
>>>> c("yellow","blue","green","red","pink","violet","brown","gold")
>>>> rep(sel.cols, 100) [ seq(1, by = 11, length.out = 8) ]
>>>
>>> [1] "yellow" "red"    "brown"  "blue"   "pink"   "gold"   "green"
>>>   "violet"
>>>
>>> It's easy to fix this so that we get the expected order, and I will do
>>> so for the next release.
>>
>> Thank you for this proposal. We are looking forward for the next release :-)
>>
>> We frequently have to colour selected boxes to be able to compare special
>> cases over different panels.
>>
>>> Having said that, it should be noted that any vectorization behaviour
>>> in lattice panel functions is a consequence of implementation and not
>>> guaranteed by design (although certainly useful in many situations).
>>> In particular, it is risky to depend on vectorization in multipanel
>>> plots, because the vectorization starts afresh in each panel for
>>> whatever data subset happens to be in that panel, and there may be no
>>> relation between the colors and the original data.
>>
>> Thank you for the warning.
>>
>>> One alternative is to use panel.superpose with panel.groups=panel.bwplot:
>>>
>>> bwplot(voice.part ~ height, data = singer, groups = voice.part, panel
>>> = panel.superpose, panel.groups = panel.bwplot, fill = sel.cols)
>>
>> This indeed works nice 'as a workaround'.
>
> Actually, I would reiterate that this is the "right solution" and the
> it's other fix that qualifies as a quick workaround (especially if you
> are considering comparing things across multiple panels).

Yes, this comparing across multiple panels was our intention.
Rainer

> -Deepayan