Hi
here is what help says
x,y
locations of grid lines at which the values in z are measured. These must
be in ascending order. By default, equally spaced values from 0 to 1 are
used. If x is a list, its components x$x and x$y are used for x and y,
respectively. If the list has component z this is used for z.
z
a matrix containing the values to be plotted (NAs are allowed). Note that
x can be used instead of z for convenience.
***your z is not a matrix***
you can try to get a structure for contour from ?interp in akima package.
Or again from help page of contour
Alternatively, use contourplot from the lattice package where the formula
notation allows to use vectors x,y,z of the same length.
besides I am not sure if contour can handle Date variable.
Best regards
Petr
r-help-bounces at r-project.org napsal dne 12.11.2009 14:40:48:
> Dear R-listers,
>
> I have a data set which combine population (site name), longitude,
> latitude, altitude, initial (for flowering of a plant), and end (also
> for flowering of the same plant) of each site.
>
> Now, I want to make contour plot to display the initial or end of the
> spatial pattern of flowering especially, I failed, although I have
> tried my best to do that.
>
> Please give me some directions on that. Thank you in advance.
>
> data and codes used are as followed:
>
> 1. data
> Population Lon Lat Alt Initial End
> ZDPd01 98.8763 28.4419 3449 2009-4-15 2009-4-25
> GSPy01 98.63446667 28.01211667 1736 2009-3-15 2009-3-28
> KDPd01 101.9054667 30.18946667 2914 2009-4-18 2009-4-29
> MKPd01 102.2027833 31.90801667 2526 2009-4-22 2009-5-1
> LXPd01 102.8014833 31.66243333 2746 2009-4-9 2009-4-21
> LXPd02 103.0387 31.40156667 2158 2009-4-7 2009-4-19
> BXPd01 102.75395 30.71616667 2180 2009-4-5 2009-4-14
> XJPd01 102.5218 31.02406667 2467 2009-4-2 2009-4-9
> BJPt01 115.95 40.45 80 2009-4-19 2009-4-26
> KMPd01 102.6225761 24.96880965 1900 2009-3-22 2009-4-11
> NYPd06 94.08488239 29.73718216 3379.591549 2009-5-1 2009-5-7
> PLPd02 95.49816933 29.90361244 2650.12 2009-4-26 2009-5-5
> CYPd01 97.01336034 28.50232574 1631.607595 2009-4-15 2009-4-23
> CYPd02 97.47131095 28.67033436 2431.802469 2009-4-21 2009-5-2
> CYPd03 97.22515032 29.13309676 3263.019417 2009-4-25 2009-5-3
> NCPt01 118.97 42.28 1300 2009-5-25 2009-6-1
> QLPd01 103.6905774 37.44786532 2403.370968 2009-5-15 2009-5-23
> LKSPt01 112.0359546 36.61293704 1664.597938 2009-4-21 2009-5-11
>
> 2. code
>
> phen<-read.delim("2009phenology.txt", header=T)
> str(phen)
> phen.1<-phen[,1:7]
> phen.1[,6]<-as.Date(phen.1[,6])
> phen.1[,7]<-as.Date(phen.1[,7])
> str(phen.1)
>
> phen.2<-phen.1[order(phen.1[,3], phen.1[,4]),]
> fix(phen.2)
>
> contour(phen.2$Lon, phen.2$Lat, phen.2$Initial) # failed
> contour(phen.2$Lon, phen.2$Lat, phen.2$Alt) # failed
>
> Regards,
>
> Mao J-F
>
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