[R] color.ramp in maptools
malbani at fas.harvard.edu
Fri Mar 26 19:54:51 CET 2004
Roger Bivand wrote:
> On Fri, 26 Mar 2004, Marco Albani wrote:
>>the moment I have some trouble understanding how the " auxvar " variable
>>is supposed to be used in the plot.Map function.
>>I don't seem to be able to get any information on this color.ramp
>>function. In fact the function doesn't seem to exist if I search for it
>>Does anyone have any insight?
> The function is not exported in the package namespace (you can read it
> using the ::: operator: maptools:::color.ramp will display it). Its usage
> is: color.ramp(nclass,color='red',nvec=NULL,type='q'), where: nclass is
> the number of classes desired in the ramp; color is the base color to
> build the ramp on; nvec is the numeric vector (or factor) from which to
> build the ramp; and type is the type of binning procedure to use (default
> quantiles, if set to "e", it will use equal-sized bins.).
Thank you. So the way I understand it is that auxvar will actually be
passed as nvec to color.ramp
I tried passing a numeric vector with the following summary stats:
Min. 1st Qu. Median Mean 3rd Qu. Max.
0.0 100.0 120.0 112.7 140.0 160.0
And on call
plot.Map(NE.HWA.pols, auxvar = NE.HWA.pols$att.data$RockDepth)
I got this error
Error in cut.default(nvec, brks, labels = FALSE, include.lowest = TRUE) :
cut: breaks are not unique
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