On 17/05/2011 8:24 AM, Pierre Bruyer wrote:
Thank you for your answer, but the function spline() (and a lot of other
function in R) can't take in its parameters the original contour which are
define by a vector, i.e. :
If you post some reproducible code to generate the contours, someone
will show you how to use splines to interpolate them.
Duncan Murdoch
##creation of breaks for colors
i<-1
paliers<- c(-1.0E300)
while(i<=length(level[,1]))
{
paliers<- c(paliers,level[i,1])
i<- i+1
}
paliers<- c(paliers, 1.0E300)
Le 17 mai 2011 à 13:05, Duncan Murdoch a écrit :
> On 11-05-17 5:58 AM, Pierre Bruyer wrote:
>> I'm a French developer (so I am sorry if my english is not perfect). I have
a problem to smooth the contours of a map. I have a dataset with 3 columns, x, y and
z, where x and y are the coordinates of my points and z is evaluate to a qualitative
elevation and his representation is a set of colors, which is define by levels.
>>
>> The problem is the curve of my contour is so linear, and I would like a
more continuous contour. I use the function fitted.contour to draw my map.
>
> If you use a finer grid of x,y values you'll get shorter segments and they
will look smoother.
>
> You might be able to use a smooth interpolator (e.g. spline()) rather than
linear interpolation, but those occasionally do strange things e.g.
>
> x<- c(1:4, 5.9, 6:10)
> y<- c(1:4, 7, 6:10)
> plot(spline(x,y, n=200), type="l")
> points(x,y)
>
> where one point is out of line with the others, but the curve
overcompensates in order to stay smooth.
>
> Duncan Murdoch
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