3 Figures and graphics basics

file_location <- "C:/YourFolder/Data/soil_data.txt"
soil_data <- read.table(file_location, header = TRUE)

names(soil_data)

##  [1] "OBJECTID" "x"        "y"        "coarse"   "clay"     "silt"    
##  [7] "sand"     "pH"       "OC"       "N"        "P"        "K"       
## [13] "CEC"      "pH_class"

str(soil_data)

## 'data.frame':    346 obs. of  14 variables:
##  $ OBJECTID: int  1 2 3 4 5 6 7 8 9 10 ...
##  $ x       : num  789504 773300 773621 766972 765574 ...
##  $ y       : num  5318238 5334066 5308045 5360016 5311956 ...
##  $ coarse  : int  12 8 14 13 12 5 50 5 35 9 ...
##  $ clay    : int  21 23 22 17 18 17 22 19 21 33 ...
##  $ silt    : int  41 72 58 54 56 74 39 63 69 60 ...
##  $ sand    : int  38 5 20 28 27 9 39 18 10 7 ...
##  $ pH      : num  6.32 5.56 5.1 7.34 6.12 6.6 7.2 7.39 7.02 6.24 ...
##  $ OC      : num  17.8 18 27.7 12.5 31.5 ...
##  $ N       : num  1.8 1.8 2.5 1.4 3.2 ...
##  $ P       : num  20.1 60.6 15 27.6 24.1 55.6 49.3 84.2 76.6 54.4 ...
##  $ K       : num  126.8 234.3 70.1 17.6 68.1 ...
##  $ CEC     : num  12.6 10.4 8.3 12.7 18.7 12.9 36 16.5 22.5 27.5 ...
##  $ pH_class: chr  "acidic" "acidic" "acidic" "neutral" ...

OBJECTID	x	y	coarse	clay	silt	sand	pH	OC	N	P	K	CEC	pH_class
1	789503.5	5318238	12	21	41	38	6.32	17.8	1.8	20.1	126.8	12.6	acidic
2	773299.8	5334066	8	23	72	5	5.56	18.0	1.8	60.6	234.3	10.4	acidic
3	773620.8	5308045	14	22	58	20	5.10	27.7	2.5	15.0	70.1	8.3	acidic
4	766972.2	5360016	13	17	54	28	7.34	12.5	1.4	27.6	17.6	12.7	neutral
5	765574.1	5311956	12	18	56	27	6.12	31.5	3.2	24.1	68.1	18.7	acidic
6	763222.3	5339957	5	17	74	9	6.60	12.4	1.4	55.6	123.9	12.9	neutral
7	763674.4	5303926	50	22	39	39	7.20	103.3	7.7	49.3	111.9	36.0	neutral
8	759071.3	5351917	5	19	63	18	7.39	17.0	1.9	84.2	0.0	16.5	neutral
9	759246.5	5337908	35	21	69	10	7.02	36.1	3.8	76.6	74.0	22.5	neutral
10	759699.9	5301880	9	33	60	7	6.24	72.8	6.7	54.4	764.4	27.5	acidic
11	756896.7	5365899	27	21	38	42	6.15	19.1	1.7	68.1	241.7	10.8	acidic
12	754942.4	5361877	20	17	57	26	6.72	15.2	1.7	74.6	139.7	15.0	neutral
13	753585.4	5311848	23	14	56	30	7.54	30.7	3.0	72.7	107.9	21.3	alkaline
14	749375.0	5327783	33	17	45	38	5.44	17.4	1.8	44.7	96.5	7.8	acidic
15	747123.7	5347773	17	20	63	17	7.29	20.2	2.2	19.6	94.9	16.6	neutral
16	745452.8	5321736	47	28	42	30	6.89	57.1	5.4	17.9	87.9	31.4	neutral
17	741023.2	5355707	29	25	54	21	7.32	50.4	5.4	86.0	657.7	33.9	neutral
18	741425.8	5323691	9	8	39	53	7.43	11.1	1.2	0.0	132.1	9.5	neutral
19	737249.5	5337649	20	16	41	44	7.26	30.2	2.9	64.6	210.0	30.2	neutral
20	737530.0	5315635	16	18	52	30	7.03	38.0	3.7	35.2	191.7	20.7	neutral
21	735121.1	5347621	4	19	54	28	3.81	49.5	3.0	24.2	45.1	10.6	acidic
22	735350.4	5329623	19	19	47	34	6.85	40.4	4.7	86.6	187.4	19.4	neutral
23	733300.3	5333599	34	18	65	17	7.61	30.5	2.7	48.2	145.2	17.8	alkaline
24	733754.7	5297578	25	7	37	55	7.24	32.2	2.5	10.6	35.0	13.6	neutral
25	728897.7	5365571	14	22	52	26	6.80	15.8	1.7	42.1	106.4	16.4	neutral
26	729505.9	5317542	18	31	53	17	6.19	83.7	8.5	33.6	106.9	35.2	acidic
27	729805.0	5293528	23	41	45	15	6.39	41.1	4.0	15.5	116.8	24.4	acidic
28	725505.1	5317497	27	18	43	39	6.87	197.3	12.5	42.9	102.4	73.7	neutral
29	723759.1	5297460	19	31	56	13	7.13	68.9	6.6	65.1	125.3	40.8	neutral
30	719027.6	5355448	15	14	73	12	7.51	11.2	1.3	71.2	187.5	12.2	alkaline
31	719633.5	5307419	21	28	36	36	6.16	33.5	3.2	23.7	162.4	24.6	acidic
32	714798.8	5373406	4	22	69	9	7.44	12.3	1.4	59.3	313.3	17.5	neutral
33	713154.9	5345368	14	27	69	3	6.46	21.0	2.2	40.0	79.6	18.4	acidic
34	707370.6	5335263	28	22	45	33	7.84	28.3	2.7	73.6	324.7	24.1	alkaline
35	704857.7	5369280	24	22	44	35	7.52	33.8	3.4	79.2	88.8	27.5	alkaline
36	705765.8	5297246	17	26	57	18	5.23	45.7	4.3	41.1	116.6	13.5	acidic
37	700340.3	5409247	11	23	54	23	8.14	38.2	2.6	21.0	104.5	24.4	alkaline
38	700623.5	5387240	7	27	60	13	6.77	17.9	1.9	53.2	337.7	14.7	neutral
39	700957.7	5361230	3	40	53	7	7.65	63.4	5.7	15.5	92.9	55.3	alkaline
40	701084.6	5351227	10	28	60	12	7.58	68.1	5.5	51.1	117.0	50.9	alkaline
41	694472.1	5399168	19	6	11	84	5.58	6.2	0.7	73.9	100.5	3.5	acidic
42	694933.8	5363158	19	15	38	48	6.24	10.3	1.3	35.0	176.8	6.8	acidic
43	692830.7	5371134	12	13	41	46	6.61	15.0	1.6	59.1	190.7	8.1	neutral
44	690239.9	5417126	9	26	59	15	7.69	18.2	1.7	24.1	119.6	20.6	alkaline
45	690317.1	5411119	16	23	64	13	7.95	20.1	1.8	62.3	20.5	20.3	alkaline
46	690703.2	5381116	15	20	55	25	7.06	14.9	1.5	92.2	235.4	15.2	neutral
47	691163.3	5345102	42	19	39	42	7.56	37.7	3.7	37.8	366.6	25.1	alkaline
48	686111.6	5427077	8	23	68	8	7.01	16.9	1.8	90.9	387.1	15.1	neutral
49	686577.7	5391068	5	21	23	56	6.84	28.2	3.0	10.7	0.0	20.9	neutral
50	687674.8	5305036	7	33	39	28	6.96	54.4	5.6	33.1	218.5	34.5	neutral
51	685600.6	5311015	26	19	48	33	7.31	38.7	3.8	10.3	122.6	31.1	neutral
52	680372.4	5406996	5	17	48	34	6.33	12.3	1.5	52.0	184.0	8.5	acidic
53	680449.6	5400997	21	25	50	25	7.66	35.3	2.1	47.8	291.5	20.5	alkaline
54	680604.4	5388992	5	6	14	80	7.56	32.8	2.4	13.3	135.2	18.3	alkaline
55	680683.4	5382991	6	10	21	69	6.25	8.9	1.1	35.0	199.1	5.9	acidic
56	680914.2	5364990	5	18	62	20	5.72	11.6	1.2	40.1	146.4	9.2	acidic
57	681066.5	5352983	2	36	37	26	6.44	28.4	2.9	23.9	115.1	26.8	acidic
58	676710.0	5380941	14	13	45	43	5.54	13.4	1.6	31.9	120.7	8.2	acidic
59	676996.0	5358943	14	15	26	59	7.46	16.2	1.6	84.5	121.5	14.7	neutral
60	672246.2	5416900	18	30	49	21	7.89	32.3	2.2	98.2	425.6	23.6	alkaline
61	672323.6	5410899	4	15	31	54	7.16	13.0	1.3	53.4	399.8	10.0	neutral
62	673351.6	5330876	8	9	65	26	6.69	13.2	1.5	67.4	128.0	11.2	neutral
63	673875.4	5290858	11	16	52	32	7.40	44.2	4.2	13.4	168.4	36.6	neutral
64	669043.9	5354836	9	18	37	45	6.75	13.1	1.6	94.6	262.2	12.0	neutral
65	669097.6	5350835	0	18	28	53	6.02	47.3	4.1	40.0	102.3	21.6	acidic
66	664505.2	5396794	12	11	14	74	7.33	29.1	2.3	0.0	264.5	17.1	neutral
67	664637.5	5386795	1	7	10	82	5.97	73.8	5.8	23.7	373.3	29.0	acidic
68	665892.2	5288761	34	20	49	31	6.84	37.3	3.4	20.0	193.5	27.9	neutral
69	664070.1	5274732	21	62	38	1	6.69	113.5	9.8	11.3	192.6	63.8	neutral
70	658251.4	5416723	23	39	35	26	7.69	32.8	3.0	77.0	467.0	27.9	alkaline
71	657845.6	5292668	16	45	43	12	6.80	123.8	8.6	17.4	156.6	64.7	neutral
72	654331.6	5410671	11	23	61	16	6.54	12.6	1.4	53.2	147.2	13.9	neutral
73	650434.7	5404620	10	29	54	17	7.33	27.2	1.9	95.4	543.3	22.1	neutral
74	651339.4	5332605	16	27	53	20	6.79	32.2	3.2	50.6	57.4	22.3	neutral
75	651748.9	5300596	2	23	41	36	6.35	40.1	4.1	47.8	151.0	20.3	acidic
76	647675.0	5306549	0	36	49	16	5.67	63.2	5.4	0.0	99.7	28.5	acidic
77	641883.8	5290470	10	31	50	19	5.84	50.8	5.2	21.1	115.5	29.0	acidic
78	633763.7	5300372	3	17	61	22	6.84	53.5	5.7	13.5	166.6	32.5	neutral
79	779726.1	5458249	7	17	37	46	6.49	57.3	5.2	16.0	67.4	17.5	acidic
80	775645.8	5464203	10	16	35	48	6.35	15.6	1.6	76.6	543.1	10.1	acidic
81	771799.3	5452147	17	11	28	61	7.07	17.4	1.7	139.4	688.1	7.0	neutral
82	765772.8	5454076	17	13	27	59	6.27	21.0	1.9	74.5	482.4	9.2	acidic
83	761720.6	5458028	3	23	44	33	5.59	24.4	2.4	43.3	282.1	9.5	acidic
84	757460.7	5477988	8	20	36	44	7.20	15.8	1.6	65.7	414.3	14.6	neutral
85	753173.0	5499946	6	17	51	31	7.00	15.7	1.5	51.8	183.2	9.9	neutral
86	751899.5	5443901	24	21	38	41	6.18	29.5	2.5	14.6	213.3	13.6	acidic
87	747536.9	5471862	30	10	26	64	6.20	12.5	1.3	63.5	130.9	7.4	acidic
88	747820.6	5449854	27	8	24	69	5.37	9.3	1.0	147.3	280.6	6.5	acidic
89	748051.9	5431845	22	22	61	17	8.08	31.1	2.4	45.2	138.7	20.6	alkaline
90	744805.7	5527855	13	18	30	52	5.34	62.7	5.2	15.0	58.6	15.9	acidic
91	746127.0	5425818	5	38	46	16	7.26	54.2	5.2	22.9	196.4	38.1	neutral
92	738751.2	5531779	9	18	34	47	6.69	16.5	1.4	95.8	218.3	11.8	neutral
93	739118.4	5503778	9	15	32	53	5.96	30.7	2.4	17.2	138.3	10.9	acidic
94	739405.1	5481764	5	23	37	40	6.07	29.8	2.9	15.7	76.6	14.3	acidic
95	735325.8	5487720	9	13	29	58	7.07	12.6	1.3	45.5	194.3	13.9	neutral
96	735871.1	5445705	18	16	33	50	5.78	22.1	2.3	50.0	305.7	10.2	acidic
97	732802.2	5527702	19	15	34	51	5.46	32.0	2.7	69.0	71.0	7.6	acidic
98	733430.1	5479691	14	11	39	51	7.21	13.9	1.4	59.4	155.2	12.9	neutral
99	730934.1	5517675	12	11	32	57	5.24	15.2	1.7	38.9	79.2	10.3	acidic
100	731168.6	5499671	15	10	23	67	5.93	9.1	1.1	49.8	243.8	5.1	acidic
101	732103.6	5427645	22	24	70	6	7.36	16.6	1.8	54.0	665.6	18.8	neutral
102	729586.7	5467637	5	8	13	79	7.07	14.4	1.2	43.5	189.0	7.4	neutral
103	727746.0	5455610	19	51	42	7	5.60	48.9	4.4	0.0	99.5	20.8	acidic
104	727896.5	5443603	9	8	24	68	6.17	9.8	0.9	76.2	145.7	4.8	acidic
105	722052.4	5431527	5	20	49	31	7.25	12.9	1.4	48.8	167.8	14.2	neutral
106	717559.4	5469493	6	14	8	77	7.39	7.9	0.9	30.5	166.7	10.4	neutral
107	711117.0	5503418	5	11	15	73	5.49	23.8	1.8	41.2	42.9	8.8	acidic
108	708801.8	5527395	7	20	25	55	5.70	23.0	2.2	17.3	120.8	8.4	acidic
109	709976.3	5437380	8	36	53	11	7.50	20.5	2.0	49.4	308.9	22.8	alkaline
110	706774.9	5529370	8	44	45	12	7.61	33.7	3.2	20.4	203.5	24.6	alkaline
111	704958.2	5515346	3	7	18	75	6.17	10.3	1.1	51.8	90.1	7.5	acidic
112	703169.4	5499315	4	30	33	37	5.90	36.8	3.2	10.3	68.9	13.4	acidic
113	703404.7	5481313	4	18	67	16	7.12	11.3	1.2	25.0	209.6	10.2	neutral
114	701274.9	5491289	5	18	45	37	6.53	22.9	2.0	29.1	53.5	9.6	neutral
115	699924.5	5441255	11	24	68	8	6.49	21.7	2.1	82.1	289.9	16.9	acidic
116	695873.4	5445206	28	26	60	14	7.11	22.7	2.4	87.3	529.5	17.7	neutral
117	690960.2	5515165	8	17	41	42	5.35	23.5	2.2	0.0	45.5	4.7	acidic
118	690084.8	5429127	11	26	63	11	7.16	17.3	1.8	22.3	233.5	14.6	neutral
119	687434.2	5479110	9	22	66	12	7.91	12.7	1.4	25.7	210.2	16.0	alkaline
120	687668.7	5461108	23	21	67	12	6.38	15.2	1.6	50.9	193.3	12.2	acidic
121	685878.0	5445078	13	21	69	9	7.55	16.0	1.6	28.5	219.8	17.1	alkaline
122	683512.7	5473059	26	25	36	40	6.93	13.1	1.4	26.8	0.0	10.1	neutral
123	677699.3	5458981	3	8	6	85	5.97	25.2	2.3	27.6	118.6	7.7	acidic
124	673751.7	5454931	3	24	12	64	6.00	22.3	2.1	64.3	139.8	12.3	acidic
125	632496.6	5550407	5	23	39	38	7.38	14.6	1.6	24.4	247.1	15.4	neutral
126	620422.9	5556246	10	27	21	52	7.43	14.2	1.5	52.7	471.5	17.1	neutral
127	610587.0	5544117	2	52	32	16	8.12	18.8	1.8	78.4	537.9	25.5	alkaline
128	608534.3	5548089	13	31	58	11	7.09	30.8	3.0	14.1	145.2	25.5	neutral
129	606269.1	5568058	7	41	41	18	7.12	45.2	3.7	35.1	263.4	26.5	neutral
130	605018.0	5512044	7	17	31	52	7.15	11.0	1.1	42.7	254.1	11.8	neutral
131	600405.0	5557980	13	21	72	7	6.34	14.7	1.6	22.8	177.0	12.8	acidic
132	598565.7	5545956	9	13	48	39	6.91	14.6	1.6	23.8	151.1	11.2	neutral
133	596031.5	5585920	4	44	47	9	6.45	21.7	2.4	28.8	431.6	20.3	acidic
134	594246.2	5569895	29	30	66	4	7.53	16.9	1.7	27.7	233.2	20.5	alkaline
135	594676.1	5537907	8	25	25	50	7.71	14.8	1.6	23.2	524.4	16.1	alkaline
136	594967.4	5515911	3	17	27	56	6.18	21.0	2.2	11.3	56.7	12.9	acidic
137	590890.7	5521855	4	32	27	42	8.02	12.2	1.3	53.3	421.6	12.3	alkaline
138	591128.2	5503860	11	39	49	12	8.05	17.7	1.4	40.0	643.0	18.9	alkaline
139	589081.3	5507835	7	20	32	48	7.23	6.3	0.7	25.1	178.2	10.4	neutral
140	586544.7	5547797	11	21	74	5	6.85	10.2	1.3	41.6	259.1	12.5	neutral
141	583967.2	5591742	5	33	59	8	7.62	32.9	3.4	32.2	349.4	34.4	alkaline
142	584918.3	5519778	4	36	60	5	7.93	17.5	1.8	65.7	585.7	19.5	alkaline
143	582760.7	5531749	11	29	63	8	8.14	12.9	1.5	38.9	355.1	19.8	alkaline
144	580709.7	5535722	17	25	72	3	7.90	13.1	1.5	20.3	239.5	19.2	alkaline
145	577029.7	5511675	11	22	64	14	7.12	11.5	1.3	51.4	196.2	14.2	neutral
146	572551.0	5547611	27	24	62	15	6.90	38.0	3.0	35.7	356.5	26.0	neutral
147	570044.3	5585571	10	12	19	69	5.85	17.2	1.5	18.2	112.3	8.0	acidic
148	570267.7	5567576	11	13	42	45	6.61	9.6	1.1	29.0	143.5	6.0	neutral
149	569275.2	5493572	4	26	72	2	7.79	12.4	1.5	36.8	196.8	14.6	alkaline
150	566877.0	5523538	44	38	52	10	8.12	20.1	2.0	70.1	534.0	26.0	alkaline
151	567113.1	5505545	7	36	59	5	7.09	21.6	2.7	22.0	245.4	25.1	neutral
152	564420.8	5557500	14	16	47	37	7.39	24.2	2.3	17.9	279.1	14.2	neutral
153	562717.9	5535478	4	42	54	4	6.85	12.5	1.4	29.6	322.0	24.5	neutral
154	558799.2	5529428	12	7	14	79	7.75	8.4	0.8	30.0	65.8	8.4	alkaline
155	554079.1	5583355	5	18	42	40	5.36	24.6	2.4	19.2	247.2	5.4	acidic
156	554991.9	5515379	14	27	66	8	7.91	10.7	1.4	34.7	194.4	18.5	alkaline
157	552857.6	5525351	8	17	78	5	7.06	12.4	1.5	68.3	274.2	14.5	neutral
158	553024.3	5513351	23	33	63	4	7.45	16.6	1.7	37.0	365.6	21.2	neutral
159	519172.3	5502901	5	14	40	45	5.96	14.9	1.4	56.3	245.4	7.6	acidic
160	510618.5	5542815	10	15	27	58	6.31	14.0	1.4	48.1	248.0	8.0	acidic
161	508615.3	5544746	16	14	25	61	5.82	8.7	1.0	44.9	142.5	8.5	acidic
162	508892.7	5526799	3	17	67	15	6.62	8.4	1.1	22.6	107.8	10.4	neutral
163	718600.3	5545446	13	12	55	33	6.71	17.2	1.8	42.6	144.8	8.7	neutral
164	712460.6	5553452	17	21	41	38	5.89	25.0	2.1	70.0	208.3	9.3	acidic
165	710165.2	5575427	36	18	53	29	7.19	17.1	1.6	41.0	85.9	16.0	neutral
166	698377.9	5559270	20	16	33	51	5.18	30.5	2.4	11.4	48.7	7.3	acidic
167	690564.4	5545167	18	28	36	36	6.07	25.4	2.6	10.6	88.5	17.5	acidic
168	686724.1	5533114	7	14	20	66	6.06	10.4	1.1	0.0	62.2	8.3	acidic
169	678247.5	5569008	6	17	40	43	6.31	30.8	2.8	0.0	151.6	12.9	acidic
170	676698.8	5534984	10	28	52	21	5.13	27.8	2.8	0.0	91.6	14.1	acidic
171	674831.1	5524958	34	38	46	16	7.74	43.2	3.9	143.2	652.7	35.4	alkaline
172	670433.2	5554906	6	38	49	13	7.07	29.7	2.9	45.0	475.5	25.0	neutral
173	668727.3	5532878	19	27	57	16	7.65	29.4	2.8	108.5	406.7	24.3	alkaline
174	664330.0	5562825	9	19	70	11	6.13	13.5	1.4	41.2	201.0	12.6	acidic
175	663096.3	5504801	2	30	58	12	6.44	20.9	2.1	13.4	82.7	17.9	acidic
176	656650.9	5538721	19	37	51	11	7.60	18.9	1.9	19.0	271.3	23.1	alkaline
177	654332.3	5562693	5	14	41	45	6.86	15.4	1.5	35.5	116.4	12.1	neutral
178	654489.6	5550694	33	41	49	9	7.39	38.7	3.7	58.9	943.0	37.3	neutral
179	654811.6	5526698	12	40	45	15	7.78	36.6	3.2	71.6	747.8	32.0	alkaline
180	655043.8	5508700	8	33	30	38	7.95	15.3	1.8	34.0	295.9	17.6	alkaline
181	648280.5	5566615	18	47	46	7	7.49	32.0	3.1	64.1	609.8	29.9	neutral
182	644521.5	5548565	47	59	36	5	5.91	48.5	4.8	0.0	405.3	30.5	acidic
183	640709.2	5534517	12	19	29	52	7.46	19.1	2.0	22.2	155.6	14.7	neutral
184	638841.6	5524488	13	20	16	64	6.83	22.8	2.1	27.0	99.0	23.8	neutral
185	636733.6	5532461	21	68	23	9	6.35	61.2	6.1	12.0	150.9	39.0	acidic
186	634925.9	5518440	6	15	37	48	6.38	9.5	1.0	19.6	179.3	9.7	acidic
187	626634.6	5540329	4	11	21	69	5.90	13.9	1.5	10.4	62.3	8.1	acidic
188	622955.2	5516280	2	13	24	63	6.66	9.3	1.1	50.2	147.3	7.5	neutral
189	658950.5	5362713	8	21	31	48	7.05	18.9	2.0	59.0	226.6	15.1	neutral
190	656694.0	5382693	9	33	34	33	6.63	44.3	5.1	17.8	110.9	32.6	neutral
191	657081.0	5352686	9	21	51	28	7.48	24.4	2.1	16.0	108.7	19.5	neutral
192	651109.7	5350613	12	22	50	28	6.67	14.2	1.6	64.4	235.0	16.2	neutral
193	646828.4	5372566	4	13	26	61	6.05	10.3	1.3	60.9	224.0	17.9	acidic
194	644931.3	5364538	6	33	40	28	7.46	59.7	5.4	24.4	100.6	39.1	neutral
195	640727.4	5380492	9	21	32	47	7.38	49.3	4.9	62.3	117.1	29.6	neutral
196	638391.3	5406468	7	9	27	63	6.54	14.2	1.4	64.7	204.4	9.0	neutral
197	636573.8	5392446	47	20	44	37	8.08	40.3	1.9	59.6	162.5	18.7	alkaline
198	636891.3	5366442	4	11	24	65	6.50	10.5	1.3	59.9	198.2	7.6	acidic
199	634627.7	5388417	13	45	33	22	7.50	66.5	6.3	54.0	192.7	54.2	alkaline
200	635093.0	5352410	20	33	42	24	7.32	24.6	2.5	45.9	155.1	26.5	neutral
201	633302.5	5336385	10	21	72	7	6.61	9.2	1.1	30.0	157.4	8.9	neutral
202	633533.8	5318379	7	34	49	16	6.24	121.2	12.2	33.5	86.8	62.0	acidic
203	634042.9	5278365	12	29	41	30	6.35	37.5	3.9	0.0	85.4	20.8	acidic
204	631636.7	5310352	8	30	34	36	6.30	43.3	4.4	43.1	319.3	23.3	acidic
205	629996.9	5282319	4	27	56	17	7.12	55.8	5.7	21.8	119.8	31.7	neutral
206	627332.9	5334307	7	31	33	36	7.10	68.3	6.5	40.2	211.9	37.1	neutral
207	627794.9	5298297	29	28	44	28	7.04	69.4	6.5	67.5	217.0	33.1	neutral
208	623949.8	5286244	6	22	42	36	5.57	30.8	3.3	10.9	56.3	10.8	acidic
209	620167.6	5424238	7	43	31	26	7.82	20.1	2.2	23.6	710.4	28.2	alkaline
210	620404.2	5406237	12	36	50	14	7.19	32.3	3.3	19.1	173.9	30.8	neutral
211	620638.0	5388237	12	30	65	5	7.54	16.0	1.7	28.2	298.6	19.3	alkaline
212	621181.7	5346233	12	25	42	34	5.78	21.9	2.2	12.1	126.5	13.0	acidic
213	621413.6	5328231	7	23	31	46	5.66	32.9	2.7	14.9	42.1	12.9	acidic
214	618957.6	5362223	16	8	16	76	5.88	12.9	1.5	57.8	239.1	6.9	acidic
215	619620.3	5312201	15	25	61	14	6.39	22.1	2.3	12.8	182.3	12.9	acidic
216	619672.0	5308201	7	49	33	18	6.86	61.6	6.3	46.6	388.9	49.7	neutral
217	620082.2	5276192	24	28	52	20	7.17	55.8	5.7	31.6	74.8	28.2	neutral
218	617109.0	5352183	7	30	41	30	6.09	36.8	3.6	26.5	73.0	11.2	acidic
219	618032.4	5280167	21	14	53	32	6.54	42.0	4.1	0.0	72.0	22.5	neutral
220	614145.3	5426159	13	39	36	25	7.87	20.6	2.2	80.6	628.0	25.2	alkaline
221	614379.5	5408160	8	31	64	6	6.48	19.1	2.0	71.2	594.1	20.8	acidic
222	614615.6	5390161	1	31	58	11	6.04	24.4	2.3	13.2	123.8	18.6	acidic
223	614901.8	5368156	9	15	37	49	6.01	12.6	1.6	0.0	58.5	11.7	acidic
224	615032.0	5358161	6	30	52	17	6.22	21.6	2.4	39.4	121.1	17.8	acidic
225	615134.7	5350158	9	19	33	47	6.94	11.8	1.4	54.0	170.5	15.4	neutral
226	615265.6	5340157	4	16	33	51	5.65	24.2	2.7	12.6	73.3	8.6	acidic
227	613651.6	5310125	26	20	46	34	7.20	35.2	3.2	41.0	211.5	20.9	neutral
228	610771.0	5378107	14	26	46	29	7.67	61.1	5.4	46.4	126.6	54.6	alkaline
229	611781.2	5300099	29	19	54	27	7.28	59.4	5.1	35.9	194.7	34.0	neutral
230	609424.0	5328078	12	39	42	19	6.50	122.1	9.1	15.9	94.5	62.5	acidic
231	609887.2	5292070	10	17	51	32	7.16	55.0	5.3	45.6	239.2	28.9	neutral
232	607372.7	5332054	13	0	0	0	5.14	251.3	16.8	0.0	78.6	61.9	acidic
233	607786.2	5300048	6	25	46	29	5.85	37.8	4.0	24.3	93.6	15.0	acidic
234	606146.5	5272012	3	27	50	23	6.32	42.4	4.4	10.3	85.2	26.9	acidic
235	603582.9	5315999	10	30	34	36	6.30	35.7	3.5	18.7	178.1	22.6	acidic
236	603816.0	5297997	8	26	46	28	5.39	28.6	3.0	21.2	94.1	13.8	acidic
237	600973.9	5366005	9	22	55	23	7.10	18.2	1.9	61.8	495.1	17.3	neutral
238	601767.3	5301971	19	31	38	30	7.36	29.1	3.0	18.1	115.1	34.0	neutral
239	601997.0	5283966	26	30	43	27	6.45	90.7	8.1	44.5	134.5	47.8	acidic
240	599354.7	5333951	5	14	39	47	6.49	14.8	1.7	47.4	137.4	12.4	acidic
241	596628.3	5389928	4	18	28	54	7.95	14.7	1.5	30.7	275.8	15.0	alkaline
242	597382.0	5331926	8	23	50	28	6.46	26.1	2.7	33.6	387.6	15.2	acidic
243	597564.0	5317924	3	27	37	36	6.05	32.3	3.4	14.0	84.9	17.4	acidic
244	595668.8	5309896	4	35	33	32	5.95	38.8	3.9	37.3	231.0	23.6	acidic
245	596131.2	5273889	6	19	47	34	6.07	35.2	3.8	10.6	74.6	22.2	acidic
246	594082.5	5277863	21	20	46	34	7.38	37.8	3.2	0.0	71.4	25.9	neutral
247	591192.3	5345847	18	20	45	35	6.32	6.1	0.8	10.7	145.1	7.3	acidic
248	591826.2	5297843	4	25	41	34	5.54	28.7	3.1	0.0	75.8	13.6	acidic
249	588918.8	5367823	22	24	45	31	7.53	32.5	2.9	69.9	352.7	19.9	alkaline
250	589102.2	5353824	5	14	38	48	6.45	13.6	1.5	31.7	116.6	10.0	acidic
251	589802.7	5299817	9	21	34	45	5.53	29.4	2.8	41.0	196.4	12.6	acidic
252	590085.4	5277812	6	24	36	41	6.03	25.4	2.8	12.8	214.5	13.5	acidic
253	587467.5	5325796	11	15	60	25	6.08	11.2	1.3	64.0	200.6	9.7	acidic
254	587701.4	5307794	13	32	35	33	6.33	43.2	4.2	25.3	123.7	26.5	acidic
255	576980.3	5363668	14	33	47	20	7.47	22.6	2.7	29.3	336.1	27.4	neutral
256	574153.8	5273606	6	22	47	31	5.34	30.7	3.4	69.1	142.8	10.6	acidic
257	566189.3	5271503	16	26	42	32	5.67	49.1	4.8	27.2	95.2	18.8	acidic
258	560168.8	5273426	7	25	41	34	5.85	31.4	3.4	29.4	71.0	15.8	acidic
259	848381.1	5411014	23	11	28	62	6.36	17.8	1.3	12.2	46.0	7.1	acidic
260	840424.0	5406921	5	20	42	38	5.22	32.5	3.0	19.1	153.9	8.9	acidic
261	838498.1	5400889	38	4	27	69	4.73	27.3	1.4	36.8	88.7	4.4	acidic
262	830191.3	5424818	20	24	40	36	5.49	40.2	3.3	0.0	64.5	7.6	acidic
263	828515.6	5402761	7	12	27	61	5.27	17.9	1.5	80.9	145.3	8.7	acidic
264	826740.9	5380728	3	18	77	5	5.36	17.0	2.0	0.0	60.4	8.3	acidic
265	822412.6	5406711	20	8	15	76	5.79	21.9	2.2	28.5	145.2	7.0	acidic
266	822864.0	5370676	6	20	58	23	6.80	15.5	1.6	66.6	157.8	11.1	neutral
267	818233.3	5420675	11	18	37	45	5.67	26.9	2.5	28.9	64.0	7.4	acidic
268	816705.3	5382628	27	24	45	31	7.27	16.3	1.6	61.8	102.7	21.7	neutral
269	812859.8	5370547	13	12	38	50	6.08	14.9	1.8	65.4	246.8	8.8	acidic
270	812996.4	5360528	6	20	45	36	6.95	19.1	2.0	36.5	141.5	12.0	neutral
271	808400.9	5406547	5	21	73	6	6.38	23.6	2.5	28.1	386.7	10.0	acidic
272	804869.5	5370467	23	18	49	33	7.37	18.9	1.9	80.6	223.5	16.0	neutral
273	802478.3	5400470	5	13	36	51	7.55	33.1	1.8	54.2	145.7	12.9	alkaline
274	800660.1	5384422	4	18	47	35	7.00	10.8	1.3	40.4	276.1	10.3	neutral
275	801013.0	5366354	17	33	58	9	6.80	27.8	2.5	96.6	442.7	21.0	neutral
276	798245.9	5418439	8	15	29	56	4.37	32.4	3.1	16.4	62.4	4.5	acidic
277	798423.6	5404427	4	32	61	7	7.55	41.9	3.2	113.6	88.0	29.3	alkaline
278	798878.6	5368397	16	20	47	33	5.43	27.7	2.8	12.0	53.5	10.8	acidic
279	796373.0	5408407	11	18	41	42	7.55	28.8	2.2	39.8	129.3	15.7	alkaline
280	794550.6	5396423	11	24	70	6	7.94	9.0	1.0	45.2	119.2	16.8	alkaline
281	794750.8	5378335	7	17	53	30	5.78	12.5	1.4	49.7	210.4	6.7	acidic
282	784293.6	5414267	11	18	76	6	7.27	10.5	1.3	66.9	352.4	11.2	neutral
283	784909.1	5364222	14	20	53	27	5.63	17.3	1.8	15.5	91.9	9.1	acidic
284	778369.1	5408191	16	19	68	13	7.78	18.1	1.6	101.2	375.1	15.3	alkaline
285	774212.3	5420157	16	16	42	42	7.63	15.1	1.7	103.9	378.8	14.7	alkaline
286	774622.5	5384144	32	20	64	16	6.23	16.3	1.8	29.4	118.8	10.4	acidic
287	774899.2	5366121	16	16	56	27	6.40	16.2	1.7	54.3	241.1	10.7	acidic
288	772025.9	5434135	6	16	43	41	5.83	15.3	1.4	91.2	206.0	10.5	acidic
289	772505.3	5392106	9	29	54	17	7.90	21.2	1.9	50.9	381.3	22.9	alkaline
290	772850.0	5370093	13	15	36	49	5.71	13.0	1.5	15.8	65.1	8.0	acidic
291	770440.8	5402094	23	23	59	18	7.81	17.1	1.5	67.8	283.4	17.6	alkaline
292	770567.5	5390130	29	24	48	28	7.03	13.8	1.5	88.3	274.0	17.6	neutral
293	768578.6	5406123	13	30	62	8	7.68	17.7	1.9	89.2	313.7	22.7	alkaline
294	768797.3	5374050	21	32	47	21	6.55	20.2	2.1	64.8	321.1	22.3	neutral
295	760132.9	5425983	8	9	21	70	7.36	12.4	1.3	67.8	150.7	7.8	neutral
296	758157.4	5423962	4	14	61	25	7.38	45.1	3.1	15.9	56.8	21.6	neutral
297	758515.3	5395946	28	37	47	16	7.23	148.1	11.2	52.6	260.9	83.7	neutral
298	754333.2	5409896	6	19	61	20	6.94	13.5	1.4	78.7	384.1	12.2	neutral
299	754614.6	5387893	10	17	73	10	6.93	15.0	1.7	50.6	285.4	13.6	neutral
300	744998.1	5357759	8	18	40	42	7.17	21.3	2.2	68.9	64.1	18.1	neutral
301	740384.7	5405734	2	26	61	14	7.26	16.5	1.7	54.0	314.0	2.7	neutral
302	738436.8	5401710	8	29	60	10	7.37	18.9	1.9	42.3	235.3	18.9	neutral
303	736615.8	5387675	8	24	61	15	7.83	35.1	3.2	33.0	0.0	32.7	alkaline
304	734362.7	5407662	7	33	39	27	5.62	17.4	1.8	42.0	255.7	21.5	acidic
305	732822.5	5369684	2	30	46	24	6.61	11.9	1.4	38.2	202.9	16.1	neutral
306	728437.5	5401587	21	26	51	23	6.96	19.3	2.1	78.2	353.2	18.4	neutral
307	728593.1	5389584	26	26	64	10	7.77	14.8	1.7	73.5	344.9	18.3	alkaline
308	724132.0	5425551	17	29	31	40	7.09	12.9	1.5	50.2	16.6	17.6	neutral
309	720668.9	5383481	15	26	48	26	7.53	11.0	1.4	35.9	198.1	19.0	alkaline
310	718258.2	5415470	5	27	61	13	7.74	14.5	1.4	72.6	334.2	18.2	alkaline
311	714389.3	5405419	2	24	61	15	7.65	13.8	1.5	57.3	218.9	19.0	alkaline
312	714567.8	5391413	8	21	64	15	7.56	17.6	1.8	90.8	231.9	17.4	alkaline
313	710259.3	5415358	9	22	40	38	7.51	10.9	1.2	67.5	203.5	15.1	alkaline
314	679435.2	5479005	35	27	60	13	6.25	25.2	2.5	10.3	0.0	14.3	acidic
315	667413.9	5480857	13	41	29	30	5.73	44.0	4.2	17.5	133.2	26.1	acidic
316	667830.4	5448853	3	32	27	41	7.21	22.0	2.1	64.5	583.4	22.2	neutral
317	661991.6	5436765	11	36	56	8	7.15	18.7	2.0	83.7	614.5	21.1	neutral
318	655285.1	5490700	6	4	9	86	5.63	7.8	0.7	45.7	82.7	5.1	acidic
319	655914.0	5442699	17	25	58	17	7.01	13.6	1.4	28.1	183.2	12.5	neutral
320	649942.5	5440626	6	38	48	14	6.40	26.3	2.7	37.4	257.7	21.5	acidic
321	644155.2	5424548	6	22	68	10	5.92	16.3	1.7	55.8	191.1	10.4	acidic
322	640078.4	5430493	6	49	45	6	7.72	19.8	2.1	0.0	264.4	24.0	alkaline
323	637333.6	5486472	4	17	41	42	6.92	13.8	1.3	54.1	265.3	9.9	neutral
324	637448.9	5478465	8	18	28	53	6.39	19.3	2.0	21.2	47.7	11.2	acidic
325	638188.8	5424477	12	27	68	5	5.86	19.2	2.2	21.6	80.6	13.6	acidic
326	635792.1	5452444	8	10	26	64	5.36	9.4	0.8	95.6	116.5	2.9	acidic
327	631951.7	5440391	12	43	30	27	7.41	26.8	2.4	34.3	346.0	21.5	neutral
328	629056.9	5508361	3	24	47	29	6.71	11.0	1.2	16.1	246.6	11.7	neutral
329	630005.1	5436366	17	30	53	17	5.90	16.7	1.9	15.6	146.0	14.2	acidic
330	627666.1	5462337	8	18	36	46	6.68	34.6	3.5	45.7	106.0	21.9	neutral
331	625455.2	5478313	13	25	25	51	6.91	38.1	3.7	24.1	148.7	24.5	neutral
332	625535.5	5472313	3	9	24	67	7.14	13.6	1.7	63.8	388.3	9.4	neutral
333	625771.4	5454315	7	11	26	63	7.49	6.0	0.7	60.5	198.0	9.0	neutral
334	626008.8	5436316	6	41	48	11	6.50	30.8	2.9	0.0	156.4	24.9	acidic
335	617326.8	5488205	6	22	22	56	6.01	13.8	1.4	28.3	126.7	10.4	acidic
336	615225.9	5496179	13	31	34	36	7.45	28.0	2.9	27.6	133.5	23.9	neutral
337	611225.1	5496124	8	9	24	68	7.60	11.7	1.4	101.4	232.3	12.3	alkaline
338	607545.4	5472076	5	13	37	50	6.24	12.5	1.5	64.9	308.4	9.2	acidic
339	605729.7	5458054	12	74	23	3	6.50	53.3	5.9	0.0	269.8	54.8	acidic
340	599414.6	5481971	26	42	53	5	7.12	45.2	4.5	28.0	258.2	37.6	neutral
341	599577.1	5469973	13	23	35	42	7.05	14.5	1.5	32.9	263.9	13.7	neutral
342	595869.6	5447893	3	20	45	35	7.46	10.1	1.1	19.3	120.8	13.0	neutral
343	591368.8	5485864	3	19	74	7	7.91	11.4	1.4	26.3	161.7	16.0	alkaline
344	585398.3	5483786	12	34	47	18	7.73	16.8	1.8	46.6	328.1	22.8	alkaline
345	583374.3	5485761	12	38	58	4	7.50	37.3	3.5	13.3	185.8	40.7	alkaline
346	581586.1	5469739	0	36	53	11	7.30	29.4	3.0	15.2	527.2	24.8	neutral

3.1 Visualization with plots

The R Graph Gallery

# We separate only two properties to make easier to work with them
pH <- soil_data$pH
OC <- soil_data$OC
N <- soil_data$N

# We also create a data.frame with those 3 variables (only for easy handling)
data <- as.data.frame(cbind(pH, OC, N))

3.1.1 Boxplots boxplot()

boxplot(pH, N, names = c("pH value", "N [%]"), ylab = "pH in water and N")

• Data to be displayed: pH and Corg.
• Labeling of the x-axis: names = c("pH value", "N [%]").
• Labeling of the y-axis: ylab = "pH in water and N".

What does the boxplot show?

3.1.2 Histograms hist()

hist(pH,
     xlab = "pH value", 
     ylab = "Frequency", 
     main = ""
     )

3.1.3 Density plots plot(density())

plot(density(pH),
     xlab = "pH value",
     ylab = "Frequency", 
     main = ""
     )

3.1.4 Scatterplots plot(x, y)

plot(N, 
     OC, 
     xlab = "OC [%]",
     ylab = "N [%]"
     )

3.1.5 Design options

Directly in the graphic routines (help with ?par)

• Set colors with col = ...
• Set symbol properties with pch = ..., sizes with cex = ...
• Set title with main = ..., axis label with xlab = ..., ylab = ...
• Set drawing area with xlim = ..., ylim = ...

After drawing a graphic

• Complete lines and points with lines(...) or points(...) respectively.
• Add captions (texts) with text(...) or mtext(...)
• Complete titles with title(...)
• Complete legend with legend(...)

Output adjustment

• main Title of the diagram
• xlab labeling of the x-axis
• ylab labeling of the y-axis
• breaks frequency classes number of bars
• col color filling of the bars
• cex gradual scaling of text size

hist(pH, 
     xlab = "pH value", 
     ylab = "Frequency", 
     main = "",
     breaks = seq(3.5, 8.5, 0.125), 
     col = "red",
     cex = 0.5
     )

3.2 All roads lead to Rome

When working with code, it is very common that there are several ways to solve the same problem.

Exercise:

• Create boxplots and histograms for clay content and P.

• Create a density of CEC distribution.

• Plot the correlations between clay content and OC.

• And now for the frequency distribution of pH_class, create one of the next plots.

In the variable pH_class, pH is classified as:

• neutral: 6.5 to 7.5
• alkaline: over 7.5
• acidic: less than 6.5

Hint: The three different version are made with a barplot(), plot() and hist()

You do need to remember the importance of factors transformation.

3.2.1 Variant A

3.2.2 Variant B

3.2.3 Variant C

3.2.3.1 Solution

See solution

# Variant A
barplot(pH_class_count$Freq, space = 0, names = pH_class_count$Var1, 
                    xlab = "pH class", ylab = "Frequency", 
                    main = "Frequency diagram of pH classes") 

# Variant B
plot(factor(soil_data$pH_class), 
     xlab = "pH class", 
     ylab = "Frequency", 
     main = "Frequency diagram of pH classes")

# Variant C
hist(as.numeric(factor(soil_data$pH_class)),
     breaks = c(0, 1, 2, 3),
     freq = TRUE,
     xaxt = "n",
     xlab = "pH class",
     ylab = "Frequency",
     main = "Frequency diagram of pH classes")

axis(side = 1, at = seq(0.5, 2.5, 1), labels = c("acidic", "alkaline", "neutral"))

3.3 Multiple plots in one figure

When you set graphical parameters in Rstudio using this method, it is important to set the properties, plot the figures and reset the properties to the way they were before. Otherwise, every time we plot something, it will follow the set parameters.

par(                              # set or query graphical parameters
  mfrow = c(1, 3),                # 1 x 3 pictures on one plot, equivalent to mfcol = c(3, 1)
  mar = c(5.1, 4.1, 4.1, 2.1),    # margins as c(bottom, left, top, right)
  oma = c(0, 0, 0, 0),            # outer margins in lines of text as c(bottom, left, top, right)
  mgp = c(3, .1, 0),              # margins line for axis title, axis label and axis line
  las = 0,                        # label axis style 
  cex.lab = 1,                    # size of the labels
  cex.axis = 1,                   # size of the axis annotation 
  xpd = FALSE                     # If FALSE, all plotting is clipped to the plot region, if TRUE, all plotting is clipped to the figure region, and if NA, all plotting is clipped to the device region.
    )
dev.off()                         # reset the original parameters

plot(…); plot(…); plot(…)

par(mfrow = c(1, 1), 
    mar = c(5.1, 4.1, 4.1, 2.1), 
    oma = c(0, 0, 0, 0), 
    mgp = c(3, 1, 0), 
    las = 0, 
    cex.lab = 1, 
    cex.axis = 1,
    )

3.4 Plots file output

In R it is possible to export images in the most common formats. The output format must be specified and the file will be generated by default in our working directory.

tiff("filename.jpg", width = 21, height = 8, units = "cm", res = 300)

par(…)
    plot(…); plot(…); plot(…)
par(…)

dev.off()

Plot export can be done in most of the image formats. E.g. .png, .jpg, .svg, .pdf.