[R] Puzzled with contour()

Ajay Narottam Shah ajayshah at mayin.org
Sun Jun 25 15:33:37 CEST 2006


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:

              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.



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