spplot question

 Hello Edzer,

I've written you in the past with an spplot question (found below or at
http://r.789695.n4.nabble.com/sppolot-fill-below-minimum-legend-value-td902841.html#a902841). 
I've recently posted a related question
(http://r.789695.n4.nabble.com/spplot-cuts-td2716237.html#a2716237) but
noticed today that it doesn't seem to be generating much interest.  I
was hoping you might be able to consider the post.  Why does the spplot
function call generate warnings and plot with a solid color when
cuts=seq(0.0,0.4,by=0.01) instead of cuts=25?

Very Humbly,
Eric Morway

On 9/11/2009 1:52 PM, Edzer Pebesma wrote:

Ah, I see. Then, if you include the 0.1 in the legend, you will not like
that the range 0.1-10 will cover the same legend space as 10-1000, on
the log-scale. To avoid this, renumber the<10 values e.g. to 9, and
label the 9 as 0.1 -- meaning that labels can not equal
as.character(cuts) anymore.
-- 
Edzer

Roger Bivand wrote:

On Fri, 11 Sep 2009, Eric Morway wrote:

Edzer,

I apologize for the confusion.  Is there an option in spplot that
fills in blank/white cells (I'm assuming they are blank because they
have a value less than the minimum cut) with the minimum color on the
legend bar (in this case green)?  About a quarter of the way in from
the left edge of the image you'll notice a "hole" in the plot due to
these cells having values less than 10.  I would like to fill these
cells in without altering the legend, if possible.

No, please see the help page for levelplot() in lattice, the at=
argument is describes as follows:

       at: numeric vector giving breakpoints along the range of 'z'.
           Contours (if any) will be drawn at these heights, and the
           regions in between would be colored using 'col.regions'.  In
           the latter case, values outside the range of 'at' will not be
           drawn at all.  This serves as a way to limit the range of the
           data shown, similar to what a 'zlim' argument might have been
           used for.  However, this also means that when supplying 'at'
           explicitly, one has to be careful to include values outside
           the range of 'z' to ensure that all the data are shown.

So you'll need to adjust your at= to accommodate all of the data.

Roger

Thanks, Eric

Edzer Pebesma wrote:

Eric, I've been reading your email over and over, but cannot
understand
what you want. I also could not find a question, despite your subject.
-- 
Edzer

Eric Morway wrote:

Hello,

I've been working on an image created with spplot and with help have
gotten it very close to the final product.  One final modification I
would like to make involves filling in grid cells with values less
than the minimum value on the legend with the color corresponding to
the bottom of the legend.  In the attached figure, the minimum legend
value is 10, but there a few spots with values as low as 0.01. These
cells are currently blank/white.  I would like to avoid including
this
value on my legend due to the color spread on the plot becoming
homologous, that is, I would like the color spread to be maximized
between 10-1000.  Were I to go from 0.01-1000, the range I'm most
interested in (10-1000) would be confined to a more narrow range of
the legend.  I have played around with trying to specify a different
number of cuts for the legend vs plot area, but this causes a
disconnect between the legend and the colors displayed for the
different grid cells.  The spplot line looks like this (image
attached):

pts<-list("sp.points",K.dat,pch=3,col="black",labels=as.character(K.dat$Kh))



cuts<-c(10,20,30,40,50,60,70,80,90,100,200,300,400,500,600,700,800,900,1000)



spplot(lzm.krige.dir["var1.pred"],at=cuts,colorkey=list(at=log10(cuts),labels=as.character(cuts)),scales=list(draw=TRUE),


 
xlab="Easting",ylab="Northing",key.space="right",cex=1.1,col.regions=terrain.colors(22),main="Hydraulic


Conductivity of Layer 2",sp.layout=list(pts))

Respectfully,
Eric Morway

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