[R] Lattice: problem with setting space between plot and legend

[David Winsemius]

On Aug 17, 2011, at 11:19 AM, Bert Gunter wrote:

> (Note: Posted at the suggetsion of David Winsemius, to whom I already
> sent a private reply).
>
> Inline Below.
>
> On Wed, Aug 17, 2011 at 7:34 AM, David Winsemius <dwinsemius at comcast.net 
> > wrote:
>>
>> On Aug 17, 2011, at 9:15 AM, mike1989 wrote:
>>
>>> Dear R Users,
>>>
>>> I am writing code to present my output data (I'm using Lattice  
>>> Package).
>>> However, it's essential for me to control space between barchart and
>>> legend.
>>> I've read the package's specification, but unfortunately I haven't  
>>> spot
>>> the
>>> information how to do this. Here's the code I've written:
>>>
>>
>> require(lattice)
>>
>>> barchart(mymatrix[,1:ncol(mymatrix)], horizontal=FALSE,
>>> box.width=1, stack=TRUE, border=FALSE, par.settings =
>>> simpleTheme(col=my_colors), lty="dotted", lend="butt",
>>
>>> key=list(space="bottom",
>>> columns=ncol(mymatrix),
>>> points=FALSE,
>>> text=list(colnames(mymatrix)),
>>> rectangles=list(border=FALSE,size=2,  
>>> col=my_colors[1:ncol(mymatrix)]),
>>> border=FALSE, rows=1, between=0.25))
>>
>> a) You ought to use spaces and linefeeds for readability
>> b) It appears you are using the key option so the documentation is  
>> in the
>> .../key section regarding placement:
>>
>> "Alternatively, [and this comes just after the description of the  
>> space=
>> options] the key can be positioned inside the plot region by  
>> specifying
>> components x, y and corner. x and y determine the location of the  
>> corner of
>> the key given by corner, which is usually one of c(0,0), c(1,0),  
>> c(1,1) and
>> c(0,1), which denote the corners of the unit square. Fractional  
>> values are
>> also allowed, in which case xand y determine the position of an  
>> arbitrary
>> point inside (or outside for values outside the unit interval) the  
>> key."
>>
>> Now I will admit that I did not understand what that last sentence  
>> regarding
>> an "arbitrary point inside the key" might mean on the first three  
>> readings.
>> I'm hoping it means a "user-determined point inside the _plot_". I  
>> also
>> cannot figure out from that paragraph or the one that follows which  
>> corner
>> of the key is being located.
>> David.
>>>
>
> I don't think so. Here's my translation of the Help file:
>
> There are 2 coordinate systems at play here, that of the plot and that
> of the key. The plot's coordinate system is native, and is used by the
> x and y components of the space component of key. The key's coordinate
> system is 0 to 1 on both axes and specifies the key coordinate that is
> placed at the x and y plot location. Hence, space = list (x=10, y =
> 2,corner = c(1,0)) says "place the right lower corner of the key at
> plot location (10,2).  Replacing the corner component by c(.5,.5)
> means "place the center of the key at that location on the plot."

Thanks, Bert;

That did clarify for me that the x and y arguments were specifying the  
plot coordinates (expressed in data variable units) of a particular  
point of the key box (specified in unit key-coordinates). Thanks for  
lessening my overall confusion.

-- 

David Winsemius, MD
West Hartford, CT