spplot question

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

------------------------------------------------------------------------ 


------------------------------------------------------------------------