Re: [R] Puzzled with contour()

From: Martin Maechler <maechler_at_stat.math.ethz.ch>
Date: Tue 27 Jun 2006 - 17:19:37 EST

>>>>> "Gabor" == Gabor Grothendieck <ggrothendieck@gmail.com> >>>>> on Mon, 26 Jun 2006 11:28:48 -0400 writes:

    Gabor> I think its often the case that one has 3 tuples and does not know
    Gabor> how to use contour with that; so, it would be nice if the contour
    Gabor> help page gave advice and an example and a pointer to the relevant
    Gabor> functions if it cannot be done by contour.

Yes, but even more importantly,
what help(contour) should really have is a \code{\link[lattice]{contourplot}} since contourplot() from package 'lattice' can deal well excellently with the situation Ajay has:

After reading his data into matrix 'm3'

> d3 <- data.frame(m3)
> summary(d3)

       x y z

 Min.   :0.00   Min.   : 20   Min.   :0.0000  
 1st Qu.:0.25   1st Qu.: 60   1st Qu.:0.0000  
 Median :0.50   Median :110   Median :0.0040  
 Mean   :0.50   Mean   :110   Mean   :0.1583  
 3rd Qu.:0.75   3rd Qu.:160   3rd Qu.:0.1410  
 Max.   :1.00   Max.   :200   Max.   :1.0000  

contourplot(z ~ x+y, data=d3)
## or nicer
contourplot(z ~ x+y, data=d3, cuts=20, region = TRUE) ## or rather use logit - transformed z values: contourplot(qlogis(z) ~ x+y, data=d3, cuts=20, region = TRUE)

    Gabor> On 6/26/06, Duncan Murdoch <murdoch@stats.uwo.ca> wrote:
>> On 6/26/2006 10:39 AM, Gabor Grothendieck wrote:
>> > I think it would be helpful if this were added to the contour help file.
>>
>> You mean an example of building up the z matrix from points, or just a
>> general discussion of the issue?
>>
>> Duncan Murdoch
>> >
>> > On 6/26/06, Duncan Murdoch <murdoch@stats.uwo.ca> wrote:
>> >> On 6/25/2006 9:33 AM, Ajay Narottam Shah wrote:
>> >> > Folks,
>> >> >
>> >> > The contour() function wants x and y to be in increasing order. I have
>> >> > a situation where I have a grid in x and y, and associated z values,
>> >> > which looks like this:
>> >>
>> >> contour() wants vectors of x and y values, and a matrix of z values,
>> >> where the x values correspond to the rows of z, and the y values to the
>> >> columns. You have a collection of points which need to be turned into
>> >> such a grid.
>> >>
>> >> There's an interp function in the akima package that can do this in
>> >> general. In your case, it's probably sufficient to do something like this:
>> >>
>> >> zmat <- matrix(NA, 3, 19)
>> >> zmat[cbind(20*x + 1, y/10 - 1)] <- z
>> >> x <- (0:2)/20
>> >> y <- (2:20)*10
>> >> contour(x,y,zmat)
>> >>
>> >> Duncan Murdoch
>> >>
>> >>
>> >> >
>> >> > x y z
>> >> > [1,] 0.00 20 1.000
>> >> > [2,] 0.00 30 1.000
>> >> > [3,] 0.00 40 1.000
>> >> > [4,] 0.00 50 1.000
>> >> > [5,] 0.00 60 1.000
>> >> > [6,] 0.00 70 1.000
>> >> > [7,] 0.00 80 0.000
>> >> > [8,] 0.00 90 0.000
>> >> > [9,] 0.00 100 0.000
>> >> > [10,] 0.00 110 0.000
>> >> > [11,] 0.00 120 0.000
>> >> > [12,] 0.00 130 0.000
>> >> > [13,] 0.00 140 0.000
>> >> > [14,] 0.00 150 0.000
>> >> > [15,] 0.00 160 0.000
>> >> > [16,] 0.00 170 0.000
>> >> > [17,] 0.00 180 0.000
>> >> > [18,] 0.00 190 0.000
>> >> > [19,] 0.00 200 0.000
>> >> > [20,] 0.05 20 1.000
>> >> > [21,] 0.05 30 1.000
>> >> > [22,] 0.05 40 1.000
>> >> > [23,] 0.05 50 1.000
>> >> > [24,] 0.05 60 0.998
>> >> > [25,] 0.05 70 0.124
>> >> > [26,] 0.05 80 0.000
>> >> > [27,] 0.05 90 0.000
>> >> > [28,] 0.05 100 0.000
>> >> > [29,] 0.05 110 0.000
>> >> > [30,] 0.05 120 0.000
>> >> > [31,] 0.05 130 0.000
>> >> > [32,] 0.05 140 0.000
>> >> > [33,] 0.05 150 0.000
>> >> > [34,] 0.05 160 0.000
>> >> > [35,] 0.05 170 0.000
>> >> > [36,] 0.05 180 0.000
>> >> > [37,] 0.05 190 0.000
>> >> > [38,] 0.05 200 0.000
>> >> > [39,] 0.10 20 1.000
>> >> > [40,] 0.10 30 1.000
>> >> >
>> >> > This looks like a nice case where both x and y are in increasing
>> >> > order. But contour() gets unhappy saying that he wants x and y in
>> >> > increasing order.
>> >> >
>> >> > Gnuplot generates pretty 3d pictures from such data, where you are
>> >> > standing above a surface and looking down at it. How does one do that
>> >> > in R?
>> >> >
>> >> > Any help will be most appreciated. A dput() of my data object is :
>> >> >
>> >> > structure(c(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
>> >> > 0, 0, 0.05, 0.05, 0.05, 0.05, 0.05, 0.05, 0.05, 0.05, 0.05, 0.05,
>> >> > 0.05, 0.05, 0.05, 0.05, 0.05, 0.05, 0.05, 0.05, 0.05, 0.1, 0.1,
>> >> > 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1,
>> >> > 0.1, 0.1, 0.1, 0.1, 0.15, 0.15, 0.15, 0.15, 0.15, 0.15, 0.15,
>> >> > 0.15, 0.15, 0.15, 0.15, 0.15, 0.15, 0.15, 0.15, 0.15, 0.15, 0.15,
>> >> > 0.15, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2,
>> >> > 0.2, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2, 0.25, 0.25, 0.25, 0.25,
>> >> > 0.25, 0.25, 0.25, 0.25, 0.25, 0.25, 0.25, 0.25, 0.25, 0.25, 0.25,
>> >> > 0.25, 0.25, 0.25, 0.25, 0.3, 0.3, 0.3, 0.3, 0.3, 0.3, 0.3, 0.3,
>> >> > 0.3, 0.3, 0.3, 0.3, 0.3, 0.3, 0.3, 0.3, 0.3, 0.3, 0.3, 0.35,
>> >> > 0.35, 0.35, 0.35, 0.35, 0.35, 0.35, 0.35, 0.35, 0.35, 0.35, 0.35,
>> >> > 0.35, 0.35, 0.35, 0.35, 0.35, 0.35, 0.35, 0.4, 0.4, 0.4, 0.4,
>> >> > 0.4, 0.4, 0.4, 0.4, 0.4, 0.4, 0.4, 0.4, 0.4, 0.4, 0.4, 0.4, 0.4,
>> >> > 0.4, 0.4, 0.45, 0.45, 0.45, 0.45, 0.45, 0.45, 0.45, 0.45, 0.45,
>> >> > 0.45, 0.45, 0.45, 0.45, 0.45, 0.45, 0.45, 0.45, 0.45, 0.45, 0.5,
>> >> > 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5,
>> >> > 0.5, 0.5, 0.5, 0.5, 0.5, 0.55, 0.55, 0.55, 0.55, 0.55, 0.55,
>> >> > 0.55, 0.55, 0.55, 0.55, 0.55, 0.55, 0.55, 0.55, 0.55, 0.55, 0.55,
>> >> > 0.55, 0.55, 0.6, 0.6, 0.6, 0.6, 0.6, 0.6, 0.6, 0.6, 0.6, 0.6,
>> >> > 0.6, 0.6, 0.6, 0.6, 0.6, 0.6, 0.6, 0.6, 0.6, 0.65, 0.65, 0.65,
>> >> > 0.65, 0.65, 0.65, 0.65, 0.65, 0.65, 0.65, 0.65, 0.65, 0.65, 0.65,
>> >> > 0.65, 0.65, 0.65, 0.65, 0.65, 0.7, 0.7, 0.7, 0.7, 0.7, 0.7, 0.7,
>> >> > 0.7, 0.7, 0.7, 0.7, 0.7, 0.7, 0.7, 0.7, 0.7, 0.7, 0.7, 0.7, 0.75,
>> >> > 0.75, 0.75, 0.75, 0.75, 0.75, 0.75, 0.75, 0.75, 0.75, 0.75, 0.75,
>> >> > 0.75, 0.75, 0.75, 0.75, 0.75, 0.75, 0.75, 0.8, 0.8, 0.8, 0.8,
>> >> > 0.8, 0.8, 0.8, 0.8, 0.8, 0.8, 0.8, 0.8, 0.8, 0.8, 0.8, 0.8, 0.8,
>> >> > 0.8, 0.8, 0.85, 0.85, 0.85, 0.85, 0.85, 0.85, 0.85, 0.85, 0.85,
>> >> > 0.85, 0.85, 0.85, 0.85, 0.85, 0.85, 0.85, 0.85, 0.85, 0.85, 0.9,
>> >> > 0.9, 0.9, 0.9, 0.9, 0.9, 0.9, 0.9, 0.9, 0.9, 0.9, 0.9, 0.9, 0.9,
>> >> > 0.9, 0.9, 0.9, 0.9, 0.9, 0.95, 0.95, 0.95, 0.95, 0.95, 0.95,
>> >> > 0.95, 0.95, 0.95, 0.95, 0.95, 0.95, 0.95, 0.95, 0.95, 0.95, 0.95,
>> >> > 0.95, 0.95, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
>> >> > 1, 1, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140,
>> >> > 150, 160, 170, 180, 190, 200, 20, 30, 40, 50, 60, 70, 80, 90,
>> >> > 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 20, 30,
>> >> > 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170,
>> >> > 180, 190, 200, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120,
>> >> > 130, 140, 150, 160, 170, 180, 190, 200, 20, 30, 40, 50, 60, 70,
>> >> > 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200,
>> >> > 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150,
>> >> > 160, 170, 180, 190, 200, 20, 30, 40, 50, 60, 70, 80, 90, 100,
>> >> > 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 20, 30, 40,
>> >> > 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180,
>> >> > 190, 200, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130,
>> >> > 140, 150, 160, 170, 180, 190, 200, 20, 30, 40, 50, 60, 70, 80,
>> >> > 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 20,
>> >> > 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160,
>> >> > 170, 180, 190, 200, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110,
>> >> > 120, 130, 140, 150, 160, 170, 180, 190, 200, 20, 30, 40, 50,
>> >> > 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180,
>> >> > 190, 200, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130,
>> >> > 140, 150, 160, 170, 180, 190, 200, 20, 30, 40, 50, 60, 70, 80,
>> >> > 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 20,
>> >> > 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160,
>> >> > 170, 180, 190, 200, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110,
>> >> > 120, 130, 140, 150, 160, 170, 180, 190, 200, 20, 30, 40, 50,
>> >> > 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180,
>> >> > 190, 200, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130,
>> >> > 140, 150, 160, 170, 180, 190, 200, 20, 30, 40, 50, 60, 70, 80,
>> >> > 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 20,
>> >> > 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160,
>> >> > 170, 180, 190, 200, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0,
>> >> > 0, 0, 0, 0, 0, 1, 1, 1, 1, 0.998, 0.124, 0, 0, 0, 0, 0, 0, 0,
>> >> > 0, 0, 0, 0, 0, 0, 1, 1, 1, 0.998, 0.71, 0.068, 0, 0, 0, 0, 0,
>> >> > 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0.998, 0.898, 0.396, 0.058, 0.002,
>> >> > 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0.998, 0.97, 0.726, 0.268,
>> >> > 0.056, 0.006, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0.996, 0.88,
>> >> > 0.546, 0.208, 0.054, 0.012, 0.002, 0, 0, 0, 0, 0, 0, 0, 0, 0,
>> >> > 0, 0, 0.998, 0.964, 0.776, 0.418, 0.18, 0.054, 0.014, 0.002,
>> >> > 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0.998, 0.906, 0.664, 0.342,
>> >> > 0.166, 0.056, 0.018, 0.006, 0.002, 0, 0, 0, 0, 0, 0, 0, 0, 0,
>> >> > 0, 0.986, 0.862, 0.568, 0.29, 0.15, 0.056, 0.022, 0.008, 0.002,
>> >> > 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0.954, 0.778, 0.494, 0.26, 0.148,
>> >> > 0.056, 0.024, 0.012, 0.004, 0.002, 0, 0, 0, 0, 0, 0, 0, 0, 0,
>> >> > 0.906, 0.712, 0.43, 0.242, 0.144, 0.058, 0.028, 0.012, 0.006,
>> >> > 0.002, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0.878, 0.642, 0.38, 0.222,
>> >> > 0.142, 0.066, 0.034, 0.014, 0.008, 0.004, 0.002, 0, 0, 0, 0,
>> >> > 0, 0, 0, 0, 0.846, 0.586, 0.348, 0.208, 0.136, 0.068, 0.034,
>> >> > 0.016, 0.012, 0.006, 0.004, 0.002, 0, 0, 0, 0, 0, 0, 0, 0.8,
>> >> > 0.538, 0.318, 0.204, 0.136, 0.07, 0.046, 0.024, 0.012, 0.008,
>> >> > 0.004, 0.002, 0.002, 0, 0, 0, 0, 0, 0, 0.762, 0.496, 0.294, 0.2,
>> >> > 0.138, 0.072, 0.05, 0.024, 0.014, 0.012, 0.006, 0.004, 0.002,
>> >> > 0.002, 0, 0, 0, 0, 0, 0.704, 0.472, 0.286, 0.198, 0.138, 0.074,
>> >> > 0.054, 0.028, 0.016, 0.012, 0.008, 0.006, 0.004, 0.002, 0.002,
>> >> > 0, 0, 0, 0, 0.668, 0.438, 0.276, 0.196, 0.138, 0.078, 0.054,
>> >> > 0.032, 0.024, 0.014, 0.012, 0.008, 0.004, 0.004, 0.002, 0.002,
>> >> > 0, 0, 0, 0.634, 0.412, 0.27, 0.194, 0.14, 0.086, 0.056, 0.032,
>> >> > 0.024, 0.016, 0.012, 0.01, 0.006, 0.004, 0.004, 0.002, 0.002,
>> >> > 0, 0, 0.604, 0.388, 0.26, 0.19, 0.144, 0.088, 0.058, 0.048, 0.026,
>> >> > 0.022, 0.014, 0.012, 0.008, 0.006, 0.004, 0.004, 0.002, 0.002,
>> >> > 0, 0.586, 0.376, 0.256, 0.19, 0.146, 0.094, 0.062, 0.052, 0.028,
>> >> > 0.024, 0.014, 0.012, 0.012, 0.008, 0.004, 0.004, 0.004, 0.002,
>> >> > 0.002, 0.566, 0.364, 0.254, 0.192, 0.148, 0.098, 0.064, 0.054,
>> >> > 0.032, 0.024, 0.022, 0.014, 0.012, 0.012, 0.008, 0.004, 0.004,
>> >> > 0.004, 0.002), .Dim = c(399, 3), .Dimnames = list(NULL, c("x",
>> >> > "y", "z")))
>> >> >
>> >> > --
>> >> > Ajay Shah http://www.mayin.org/ajayshah
>> >> > ajayshah_at_mayin.org http://ajayshahblog.blogspot.com
>> >> > <*(:-? - wizard who doesn't know the answer.
>> >> >
>> >> > ______________________________________________
>> >> > R-help@stat.math.ethz.ch mailing list
>> >> > https://stat.ethz.ch/mailman/listinfo/r-help
>> >> > PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
>> >>
>> >> ______________________________________________
>> >> R-help@stat.math.ethz.ch mailing list
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>> >>
>> >
>> > ______________________________________________
>> > R-help@stat.math.ethz.ch mailing list
>> > https://stat.ethz.ch/mailman/listinfo/r-help
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>>
>>

    Gabor> ______________________________________________
    Gabor> R-help@stat.math.ethz.ch mailing list
    Gabor> https://stat.ethz.ch/mailman/listinfo/r-help     Gabor> PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html

R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Tue Jun 27 17:25:01 2006

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