adjusting levelplot color scale to data

On Nov 6, 2011, at 10:08 PM, Lanna Jin wrote:

Hi guys,

I have a matrix with values varying from approximately -0.7 to 0.33  
that I
want to create a heatmap/levelplot with.

When I execute the levelplot function for my matrix, I end up  
getting colors
that are adjusted to the max and min rather than around 0. In other  
words,
ideally I would like to have a color ramp that goes from red  
(negative
number), to white (0), to blue (positive); however, right now the  
value 0 is
in the blue.

Any insight on how to address this problem?

?levelplot  # which leads to"
?level.colors  # which in turn leads to:
? colorRamp

color.palette =    colorRampPalette(c("red", "white", "blue"))
levelplot(as.matrix(dat), at=seq( -.8, .4, length=31),  
col=color.palette(30) )

And next time, please post the output of dput rather than a mangled  
print() output.
-- 
David.
Thanks in advance!

example...
my matrix "y" looks something like this
               A                 B                      C
D                    E
row1         -0.5046406 -0.021579587    -0.4419101 -0.2999195330
-0.4845047
row2         -0.3070091 -0.059065936     0.3329806 -0.0519335420
-0.5766368
row3         -0.7271707  0.073282855    -0.3181990 -0.2485017700
-0.5732781
row4          0.3329806 -0.017762750    -0.1513197 -0.1016354970
0.2528442

levelplot(y) yields a color scale from red (-0.8 to 0.2) to blue  
(0.2 to
0.4)
I'd want the color scale to be from red (-0.8 to 0) to blue (0 to  
0.4)

-----
Lanna
--
View this message in context: http://r.789695.n4.nabble.com/adjusting-levelplot-color-scale-to-data-tp3997342p3997342.html
Sent from the R help mailing list archive at Nabble.com.

______________________________________________
R-help at r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
David Winsemius, MD
West Hartford, CT

adjusting levelplot color scale to data

Thread (4 messages)