Hi Jannis,
thanks a lot for your reply. Unfortunately the solution you proposed
does not work.
Maybe the reason is, that plot.Map only accepts hsv colours and I do not
know to convert the rgb colours to the right colour space.
Isn't there a possibility to specify minimal an maximal values when
using colorRampPalette to only choose a certain part of the
colorRamp(Palette)? I could than define a new colorset jet.colors2,
which is picks out the colours between min(Vector)/10 and max(Vector)/10?
jet.colors = colorRampPalette(c("#00007F", "blue", "#007FFF",
"cyan", "#7FFF7F", "yellow", "#FF7F00",
"red", "#7F0000"))
Intervalls <- cut(as.numeric(Matrix[,nc]),n, na.rm=TRUE) }
fgs <- jet.colors(n)[Intervalls]
Maybe this is a bit confusing...
Thanks anyway for any help!
Katrin
Jannis schrieb:
Hi Katrin,
your problem is not related to maptools, rather to the base function
"colorRampPalette". In my opinion the easiest way to get what you want is to
use colorRamp:
Vector=c(2,3,4,5,6)
color.ramp <- colorRamp(c('white','black'))
map.colors <- color.ramp(Vector/10)
The 10 refers to the maximum value that you specified. You just have to adjust
the colors.
HTH
Jannis
--- schaber <kscha...@ipp.mpg.de> schrieb am Di, 21.9.2010:
Von: schaber <kscha...@ipp.mpg.de>
Betreff: [R] Colorramp in Maptools, how to choose min and max values for the
fg= argument
An: r-help@r-project.org
Datum: Dienstag, 21. September, 2010 15:42 Uhr
Hello,
I am using maptools for plooting geographical data.
The colour of the region indicates some region dependent
value (population for example).
I pass the colours of the regions to the plot.Map function
by defining the foreground colour:
jet.colors = colorRampPalette(c("#00007F", "blue",
"#007FFF", "cyan", "#7FFF7F", "yellow", "#FF7F00",
"red", "#7F0000"))
n=100
cols <- jet.colors(n)
Intervalls = cut(as.numeric(Vector),n, na.rm=TRUE)
fgs <-cols[Intervalls] ## is there some
option/possibility here to choose colours differently ??
plot.Map(Shape.map, fg=fgs, ol=NA, bty="n", xlab="",
ylab="", xaxt="n", yaxt="n")
My problem is the following: I would like to choose minimal
and maximal value of the colour palette, different from the
minimal and maximal values of the Vector. For example:
Vector=c(2,3,4,5,6), but the maximal colour should
correspond to 10 and the minimal to 0.
I know, that maptools is not the most actual solution to
plot maps, but I am building on an old code and therefore do
not want to change it.
I would very much appreciate any help or hints!!
Katrin
-----Integrierter Anhang folgt-----
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