Information Visualization (3) - R 그래픽 기초 (원 그리기)

1. 원 그리기

원을 그리는 간단한 R 함수는 없다.

아래는 다각형을 가지고 대략적으로 원을 그리는 방법이다.

 

> plot.new()

> plot.window(xlim=c(-1.1,1.1), ylim=c(-1.1,1.1), asp=1)

> theta=seq(0,2*pi, length=72) // 180° = π, 2π 즉, 360° 를 72 로 나눈 것이므로 Change of angle = 5° 

> x=cos(theta)

> y=sin(theta)

> lines(x,y)

>  

 

 

 

 

위의 그림에서 c = 1 이라고 하면,

좌표 X = (a,b) = (a/1, b/1) = (cosA, sinA) 가 된다.

 

theta = seq(0,2*pi, length=72) 의 간격대로 해당 값들을 구해보면 아래와 같다.

아래와 같은 72개의 점을 이은 셈이되는 것이다.

 

#	theta=seq(0,2*pi, length=72)	cos(theta)	sin(theta)
0	0	1.0000	0.0000
1	0.087266463	0.9962	0.0872
2	0.174532925	0.9848	0.1736
3	0.261799388	0.9659	0.2588
4	0.34906585	0.9397	0.3420
5	0.436332313	0.9063	0.4226
6	0.523598776	0.8660	0.5000
7	0.610865238	0.8192	0.5736
8	0.698131701	0.7660	0.6428
9	0.785398163	0.7071	0.7071
10	0.872664626	0.6428	0.7660
11	0.959931089	0.5736	0.8192
12	1.047197551	0.5000	0.8660
13	1.134464014	0.4226	0.9063
14	1.221730476	0.3420	0.9397
15	1.308996939	0.2588	0.9659
16	1.396263402	0.1736	0.9848
17	1.483529864	0.0872	0.9962
18	1.570796327	0.0000	1.0000
19	1.658062789	-0.0872	0.9962
20	1.745329252	-0.1736	0.9848
21	1.832595715	-0.2588	0.9659
22	1.919862177	-0.3420	0.9397
23	2.00712864	-0.4226	0.9063
24	2.094395102	-0.5000	0.8660
25	2.181661565	-0.5736	0.8192
26	2.268928028	-0.6428	0.7660
27	2.35619449	-0.7071	0.7071
28	2.443460953	-0.7660	0.6428
29	2.530727415	-0.8192	0.5736
30	2.617993878	-0.8660	0.5000
31	2.705260341	-0.9063	0.4226
32	2.792526803	-0.9397	0.3420
33	2.879793266	-0.9659	0.2588
34	2.967059728	-0.9848	0.1736
35	3.054326191	-0.9962	0.0872
36	3.141592654	-1.0000	0.0000
37	3.228859116	-0.9962	-0.0872
38	3.316125579	-0.9848	-0.1736
39	3.403392041	-0.9659	-0.2588
40	3.490658504	-0.9397	-0.3420
41	3.577924967	-0.9063	-0.4226
42	3.665191429	-0.8660	-0.5000
43	3.752457892	-0.8192	-0.5736
44	3.839724354	-0.7660	-0.6428
45	3.926990817	-0.7071	-0.7071
46	4.01425728	-0.6428	-0.7660
47	4.101523742	-0.5736	-0.8192
48	4.188790205	-0.5000	-0.8660
49	4.276056667	-0.4226	-0.9063
50	4.36332313	-0.3420	-0.9397
51	4.450589593	-0.2588	-0.9659
52	4.537856055	-0.1736	-0.9848
53	4.625122518	-0.0872	-0.9962
54	4.71238898	0.0000	-1.0000
55	4.799655443	0.0872	-0.9962
56	4.886921906	0.1736	-0.9848
57	4.974188368	0.2588	-0.9659
58	5.061454831	0.3420	-0.9397
59	5.148721293	0.4226	-0.9063
60	5.235987756	0.5000	-0.8660
61	5.323254219	0.5736	-0.8192
62	5.410520681	0.6428	-0.7660
63	5.497787144	0.7071	-0.7071
64	5.585053606	0.7660	-0.6428
65	5.672320069	0.8192	-0.5736
66	5.759586532	0.8660	-0.5000
67	5.846852994	0.9063	-0.4226
68	5.934119457	0.9397	-0.3420
69	6.021385919	0.9659	-0.2588
70	6.108652382	0.9848	-0.1736
71	6.195918845	0.9962	-0.0872
72	6.283185307	1.0000	0.0000

 

 

#	theta=seq(0,2*pi, length=72)	cos(theta)	sin(theta)
0	0	1.0000	0.0000
1	0.087266463	0.9962	0.0872
2	0.174532925	0.9848	0.1736
3	0.261799388	0.9659	0.2588
4	0.34906585	0.9397	0.3420
5	0.436332313	0.9063	0.4226
6	0.523598776	0.8660	0.5000
7	0.610865238	0.8192	0.5736
8	0.698131701	0.7660	0.6428
9	0.785398163	0.7071	0.7071
10	0.872664626	0.6428	0.7660
11	0.959931089	0.5736	0.8192
12	1.047197551	0.5000	0.8660
13	1.134464014	0.4226	0.9063
14	1.221730476	0.3420	0.9397
15	1.308996939	0.2588	0.9659
16	1.396263402	0.1736	0.9848
17	1.483529864	0.0872	0.9962
18	1.570796327	0.0000	1.0000
19	1.658062789	-0.0872	0.9962
20	1.745329252	-0.1736	0.9848
21	1.832595715	-0.2588	0.9659
22	1.919862177	-0.3420	0.9397
23	2.00712864	-0.4226	0.9063
24	2.094395102	-0.5000	0.8660
25	2.181661565	-0.5736	0.8192
26	2.268928028	-0.6428	0.7660
27	2.35619449	-0.7071	0.7071
28	2.443460953	-0.7660	0.6428
29	2.530727415	-0.8192	0.5736
30	2.617993878	-0.8660	0.5000
31	2.705260341	-0.9063	0.4226
32	2.792526803	-0.9397	0.3420
33	2.879793266	-0.9659	0.2588
34	2.967059728	-0.9848	0.1736
35	3.054326191	-0.9962	0.0872
36	3.141592654	-1.0000	0.0000
37	3.228859116	-0.9962	-0.0872
38	3.316125579	-0.9848	-0.1736
39	3.403392041	-0.9659	-0.2588
40	3.490658504	-0.9397	-0.3420
41	3.577924967	-0.9063	-0.4226
42	3.665191429	-0.8660	-0.5000
43	3.752457892	-0.8192	-0.5736
44	3.839724354	-0.7660	-0.6428
45	3.926990817	-0.7071	-0.7071
46	4.01425728	-0.6428	-0.7660
47	4.101523742	-0.5736	-0.8192
48	4.188790205	-0.5000	-0.8660
49	4.276056667	-0.4226	-0.9063
50	4.36332313	-0.3420	-0.9397
51	4.450589593	-0.2588	-0.9659
52	4.537856055	-0.1736	-0.9848
53	4.625122518	-0.0872	-0.9962
54	4.71238898	0.0000	-1.0000
55	4.799655443	0.0872	-0.9962
56	4.886921906	0.1736	-0.9848
57	4.974188368	0.2588	-0.9659
58	5.061454831	0.3420	-0.9397
59	5.148721293	0.4226	-0.9063
60	5.235987756	0.5000	-0.8660
61	5.323254219	0.5736	-0.8192
62	5.410520681	0.6428	-0.7660
63	5.497787144	0.7071	-0.7071
64	5.585053606	0.7660	-0.6428
65	5.672320069	0.8192	-0.5736
66	5.759586532	0.8660	-0.5000
67	5.846852994	0.9063	-0.4226
68	5.934119457	0.9397	-0.3420
69	6.021385919	0.9659	-0.2588
70	6.108652382	0.9848	-0.1736
71	6.195918845	0.9962	-0.0872
72	6.283185307	1.0000	0.0000

 

 

 

 

2. 또 다른 예제

 

 

> x1 = seq(0, 1, length = 20)

> y1 = rep(0, 20) // 0 을 20번 반복

> x2 = rep(0, 20)

> y2 = seq(0.75, 0, length = 20)

> plot.new()

> plot.window(xlim = c(0, 1), ylim = c(0,0.75), asp = 1)

> segments(x1, y1, x2, y2) // (x1, y1) 에서 (x2, y2) 로 선 긋기

 

	from		to
	x1	y1	x2	y2
0	0.00	0	0	0.750
1	0.05	0	0	0.713
2	0.10	0	0	0.675
3	0.15	0	0	0.638
4	0.20	0	0	0.600
5	0.25	0	0	0.563
6	0.30	0	0	0.525
7	0.35	0	0	0.488
8	0.40	0	0	0.450
9	0.45	0	0	0.413
10	0.50	0	0	0.375
11	0.55	0	0	0.338
12	0.60	0	0	0.300
13	0.65	0	0	0.263
14	0.70	0	0	0.225
15	0.75	0	0	0.188
16	0.80	0	0	0.150
17	0.85	0	0	0.113
18	0.90	0	0	0.075
19	0.95	0	0	0.038
20	1.00	0	0	0.000

 

 

	from		to
	x1	y1	x2	y2
0	0.00	0	0	0.750
1	0.05	0	0	0.713
2	0.10	0	0	0.675
3	0.15	0	0	0.638
4	0.20	0	0	0.600
5	0.25	0	0	0.563
6	0.30	0	0	0.525
7	0.35	0	0	0.488
8	0.40	0	0	0.450
9	0.45	0	0	0.413
10	0.50	0	0	0.375
11	0.55	0	0	0.338
12	0.60	0	0	0.300
13	0.65	0	0	0.263
14	0.70	0	0	0.225
15	0.75	0	0	0.188
16	0.80	0	0	0.150
17	0.85	0	0	0.113
18	0.90	0	0	0.075
19	0.95	0	0	0.038
20	1.00	0	0	0.000