R is plotting a line way outside of the chart area

Question

I am simply plotting some forecast errors, however one of my lines is plotting way outside of the chart area when I am using R's plot function

The data is as follows:

> Errors
         1.week      2.weeks      4.weeks     8.weeks
1    -0.8315842   -2.0770613   -1.5939279  -1.0221132
2     2.3557692    1.6248861    3.7038422   5.1803585
3     4.5628527    3.7731578    6.3575075   9.1854482
4   -13.9020725  -13.8751169   -9.9692492  -5.7205310
5   -26.2018878  -25.6789948  -19.6533859 -14.5865603
6   -15.4871932  -15.2419860   -6.8434238  -0.8066797
7   -14.1347094  -14.2751777   -4.5532670   2.5371869
8     7.6573971    7.0516291   20.0454082  29.5035655
9    14.2423208   11.7158540   26.8344705  38.9592733
10   12.9404280   10.4012970   23.8946655  35.4711499
11   13.5389572   11.8270242   22.4562988  32.0706150
12  -16.0386215  -17.8927906   -9.0232955  -0.9692534
13   -8.5479951  -11.4090786   -3.6729858   3.3122453
14  -17.4529120  -21.1515732  -13.8185905  -7.4398603
15  -26.7000634  -32.3277592  -23.1025683 -15.1729123
16   -4.0032531  -12.2613379   -1.8825783   6.7213671
17    8.8957503   -0.9585969    9.9365482  19.0748503
18   32.0322364   19.9301513   34.8202923  46.4041208
19   28.0687543   13.6083628   31.6832461  45.0969812
20   -3.0728661  -16.5312407   -0.9657741  10.3036339
21   11.7878788   -3.0478064   13.8424842  25.9771667
22    9.9892550   -4.9871205   11.5740132  23.2690438
23   22.8998538    6.0118306   22.7025023  35.3195641
24    5.7808321  -10.5933649    4.4892100  17.1939799
25   -6.0924242  -21.5923200   -9.2917299   2.1220339
26  -11.7374904  -28.1082658  -15.9798464  -4.1112579
27  -15.0147630  -29.3107975  -18.0836088  -6.8478348
28  -24.9128044  -38.4231537  -27.1156275 -15.6860608
29  -37.9817750  -51.6920999  -39.2222444 -25.5189189
30  -13.6706635  -27.6301887  -12.9572997   4.1337481
31   11.1107518   -1.6798887   12.6577970  30.1665708
32   31.8661224   19.8344487   34.2043033  52.8466940
33  -10.3451693  -20.2538434   -7.4683061   9.4857313
34  -13.6655462  -25.3717809  -11.4776440   7.5315424
35   11.2209802   -4.4268833   11.5400743  34.4884934
36   17.5595027   -4.1725697   12.6989773  37.6937120
37   72.3065693   41.3124760   61.7028494  93.0466741
38   89.8718428   55.3121569   74.5758621 107.7117030
39   63.0495238   35.4953908   50.1743506  77.7465922
40    4.5273250  -13.0854353   -2.6323285  18.1108514
41  -35.0096805  -48.1653640  -40.5522281 -23.7343486
42  -38.8347996  -52.1927711  -44.3939981 -26.6579849
43  -22.7564612  -40.4697479  -30.9755202  -8.8881556
44  -13.3679435  -33.7536109  -23.0032210   2.4724771
45  -21.5969388  -39.8752151  -29.9660974  -5.3971963
46  -22.2257732  -40.7611160  -30.0873218  -2.5576712
47   41.9854318   17.0388007   32.5581635  72.6495345
48   -4.7979058  -22.0000000   -9.4891390  22.1506720
49    0.8379237  -16.0771325   -2.3059105  31.0642555
50  -48.0432432  -64.6712707  -52.6205779 -23.2243465
51  -31.9405286  -50.1658080  -38.1287671  -6.7165479
52   13.3228700   -6.7078972    5.6320178  39.4271923
53   -9.9223744  -28.5279383  -18.3334270  10.8911537
54  -53.0358796  -69.7852611  -60.7242951 -33.7608786
55  -89.4042056 -106.8017795  -97.2221262 -66.1765325
56 -103.2912736 -117.4078156 -109.6670551 -81.5685855
57  -72.8317422  -89.7210127  -80.3448276 -46.6401129
58  -10.6460606  -33.5872690  -21.9263346  23.1584507
59   44.2416769   18.7887617   30.1124849  78.4170944
60   44.5294118   20.8873684   30.3804447  73.9218079
61   10.4536213  -11.1676424   -2.9950724  35.7541848
62  -13.4498715  -33.8472297  -26.4354588  10.9618605
63  -63.7424837  -83.6746464  -77.0424528 -42.0920245
64  -48.7203166  -74.8127054  -65.6121866 -20.2087413
65  -54.8806366  -77.7627958  -69.0863171 -28.6426332
66  -23.3034759  -46.2179700  -37.3916828   3.1970803
67   -0.4412955  -23.6060606  -14.4324853  28.0687361
68  -39.1934605  -58.2712826  -50.0247934 -13.7366842
69   -6.1793103  -26.9323006  -17.4225871  21.8382838
70  -67.7006993  -86.3950260  -77.7722806 -44.0970399
71  -95.0128023 -112.5663925 -104.3164426 -73.0256679
72  -58.8480463  -81.8627685  -71.4795383 -31.1377660
73  -31.9423077  -54.7657492  -45.3222698  -3.9940266
74   19.1490964   -3.2852665    5.1545455  50.2359800
75   11.1428571   -7.3954082    0.8880652  43.2303546
76   36.2714724   16.8534538   27.1051243  74.8324168
77  -18.1261682  -37.0353403  -27.1089450  18.6923529
78   -4.6456693  -25.0848244  -14.1691176  37.1199284
79  -55.9234450  -70.8848485  -61.7751479 -22.0358990
80  -80.6779935  -92.1077763  -84.1910700 -54.3332299
81  -63.1845140  -74.0436590  -66.2472325 -38.5645570
82  -27.2136895  -45.7618041  -30.1320755  20.0032362
83  -45.6570458  -61.3812950  -45.2886109   0.1458056
84   59.9193825   35.7708029   65.4523810 142.0542107
85   77.8921739   53.8424963   87.0364701 170.8487600
86  191.6063269  163.8654573  209.0661157 321.5901464
87   62.0849558   46.1521906   84.5931883 167.5243004
88   92.6666667   81.5545171  126.6058394 210.9166035
89    3.2517986   -2.0382166   30.7330657  87.3248731
90  -19.4141049  -20.6461039    7.3760903  55.6041667 

Below is the code I have used to plot these.

x1 = rep(1:90)

z1 = Errors[[1]]
z2 = Errors[[2]]
z3 = Errors[[3]]
Z4 = Errors[[4]]

plot(x1,z1,type="l",col="red", bty="L", xlab="Forecast Days",ylab="Error") #Plot first line
points(x1,z2,type="l",col="blue") #Add second
points(x1,z3,type="l",col="darkgoldenrod2") #Add third 
points(x1,z4,type="l", lwd=3, col="green") #Add fourth

When the fourth line is plotted, it is way above the others, off the chart area and partially outside of the viewing window. When I have plotted them in the reverse order (4th to 1st) the 4th line plots fine and the 3rd to 1st plot way below the chart area in a similar fashion. I'm getting no sort of error message and I can't find any other examples of this to understand why this is happening.

I have used the same code and method to plot the original forecast data (the data the errors have been calculated for) and had no such issues.

I know I can use ggplot2 also for charting, however I do still use this method sometimes. Any help is appreciated.

Using some suggested changes to the code to include the ylim still produces a similar result:

plot(x1,z1,type="l",col="red", bty="L", xlab="Forecast Days",ylab="Error", ylim = c(min(Errors),max(Errors)))  #Plot first destination
points(x1,z2,type="l",col="blue")                                                #Addition of second destination
points(x1,z3,type="l",col="darkgoldenrod2")                                               #Addition of a third destination
points(x1,z4,type="l", lwd=3, col="green")                                     #Addition of a third destination

The fourth line has come down but is still way off from where it should be as the data is all similar.

Answer 1

The reason why one of lines falls outside the plotting area is probably because the coordinates of the plotting area are calculated from the data that you use in your initial plot()command.

This can be easily rectified by setting the y-axis range by hand. You can do this by using the argument ylim() in the plotting command. Here I just calculated the minimum and the maximum from your data, and used those as y-axis limits.

This should do the trick:

plot(x1,z1,type="l",col="red", bty="L", xlab="Forecast Days",ylab="Error",ylim=c(min(Errors),max(Errors))) #Plot first line
points(x1,z2,type="l",col="blue") #Add second
points(x1,z3,type="l",col="darkgoldenrod2") #Add third 
points(x1,Z4,type="l", lwd=3, col="green") #Add fourth

Another option is to use the matplot() function:

matplot(Errors, type="l")