[R] windrose color ramp issue

[Adrienne Wootten]

Greetings!

I'm having an issue with the windrose produced by the windrose
function from the circular package.  For our weather stations in North
Carolina I'm helping with a script which takes hourly wind speed and
direction data to create windroses for our end users.  One of the
stations in the mountains frequently reaches wind speed of 40 to 60
mph and in storms can reach wind speed over 80 mph.  This has brought
up an issue with the color ramp.

Currently the color ramp works one of two ways:

#1) Holding the pedal colors fixed:

incrspeeds = 2 # fills out the increments argument
pedalcolors =  c("darkblue","blue","royalblue","darkturquoise","forestgreen","green","yellowgreen","yellow4","yellow","orange","red","darkred","violetred","mediumorchid","purple")

#or 2) Making the pedal colors dynamic based on the increments and the
max wind speed.

incrspeeds = 2 # fills out the increments argument

breaks=seq(0,round(maxwind),incrspeeds) # maxwind is the maximum wind speed
numcolors=length(breaks)

if(numcolors>length(pedalcolors)){
pedalcolors=rev(rainbow(numcolors))
}

# In either case the result ends up in the wind rose function

rose=windrose(wr,breaks=NULL,bins=numpedals,increment=incrspeeds,main=NULL,fill.col=pedalcolors,plot.mids=FALSE,units="degrees",template="geographics",ticks=FALSE,osize=0.05,cir.ind
=0.05,cex=0.9,zero=NULL,rotation=NULL,right=FALSE,shrink=NULL,label.freq=TRUE,calm=c("0"),number.calm=TRUE)

The issue when there are really large wind speeds in the first case,
the windrose wraps the color ramp twice in both the legend and the
windrose itself, and then gives only white for the remaining bands of
each pedal.  For the second case, when pedalcolors will have the same
number of colors as numcolors, the legend has the right color ramp,
but the pedals of the windrose don't have all the colors that are
passed to it.  Say pedalcolors has 40 colors, which are included in
the legend, but the windrose only includes the first 16 colors in
pedalcolors.

Any thoughts as to why this might be happening in either case?  Thanks!

Adrienne

-- 
Adrienne Wootten
Graduate Research Assistant
State Climate Office of North Carolina
Department of Marine, Earth and Atmospheric Sciences
North Carolina State University