Plot based on variable name

Question

I am using this code to plot my dataframe. The statistics variable contains two values: "mean" and "sd".

ggplot(NDVIdf_forplot, aes(x = statistic, y= value, group = ID)) + geom_line()

If I use that code the graph includes both the "mean" and "sd" categories. I want to use only those observations that are in the "mean" class of the statistic variable and later use the "sd" class to plot geom_errorbar

I used this code before but did not manage to create what I want:

ggplot(NDVIdf_forplot,aes(x=mean,y=value))+geom_errorbar(aes(ymin=NDVI_mean-NDVI_sd, ymax=NDVI_mean+NDVI_sd), width=0.1)+geom_line()+geom_point()

edit ---

The data I want to plot look like this (I'm showing only the top rows). The idea is to use NDVI_mean to create the lines and NDVI_sd to create the error bars on the same graph

> NDVIdf_forplot
    ID    statistic       value
1    1    NDVI_mean 0.052957208
2    2    NDVI_mean 0.044501794
3    3    NDVI_mean 0.077902512
4    4    NDVI_mean 0.141576609
5    5    NDVI_mean 0.653835647
6    6    NDVI_mean 0.716164870
7    7    NDVI_mean 0.386612348
8    8    NDVI_mean 0.486527816
9    9    NDVI_mean 0.226190208
10  10    NDVI_mean 0.573239754
11   1      NDVI_sd 0.008259909
12   2      NDVI_sd 0.015453091
13   3      NDVI_sd 0.099944407
14   4      NDVI_sd 0.091479545
15   5      NDVI_sd 0.223150965
16   6      NDVI_sd 0.074045394
17   7      NDVI_sd 0.058177949
18   8      NDVI_sd 0.109762451
19   9      NDVI_sd 0.019822312
20  10      NDVI_sd 0.104795771
21   1  NDVI_mean.1 0.081417705
22   2  NDVI_mean.1 0.036114126
23   3  NDVI_mean.1 0.037729680
24   4  NDVI_mean.1 0.016398037
25   5  NDVI_mean.1 0.052672604
26   6  NDVI_mean.1 0.024580946
27   7  NDVI_mean.1 0.064811390
28   8  NDVI_mean.1 0.119724256
29   9  NDVI_mean.1 0.078961665
30  10  NDVI_mean.1 0.041025489
31   1    NDVI_sd.1 0.016093458
32   2    NDVI_sd.1 0.027927592
33   3    NDVI_sd.1 0.046937888
34   4    NDVI_sd.1 0.011805721
35   5    NDVI_sd.1 0.026467984
36   6    NDVI_sd.1 0.028896611
37   7    NDVI_sd.1 0.016313583
38   8    NDVI_sd.1 0.066647683
39   9    NDVI_sd.1 0.022800589
40  10    NDVI_sd.1 0.015085673
41   1  NDVI_mean.2 0.063375514
42   2  NDVI_mean.2 0.086191853
43   3  NDVI_mean.2 0.092580942
44   4  NDVI_mean.2 0.144053635
45   5  NDVI_mean.2 0.696155509
46   6  NDVI_mean.2 0.252707792
47   7  NDVI_mean.2 0.144636380
48   8  NDVI_mean.2 0.757321462
49   9  NDVI_mean.2 0.689617575
50  10  NDVI_mean.2 0.179591653
51   1    NDVI_sd.2 0.010017152
52   2    NDVI_sd.2 0.023206464
53   3    NDVI_sd.2 0.106580902
54   4    NDVI_sd.2 0.097440674
55   5    NDVI_sd.2 0.231063744
56   6    NDVI_sd.2 0.043961963
57   7    NDVI_sd.2 0.010335935
58   8    NDVI_sd.2 0.061841114
59   9    NDVI_sd.2 0.048363788
60  10    NDVI_sd.2 0.111704779
61   1  NDVI_mean.3 0.048932939
62   2  NDVI_mean.3 0.110942174
63   3  NDVI_mean.3 0.080362752
64   4  NDVI_mean.3 0.132868790
65   5  NDVI_mean.3 0.682639604
66   6  NDVI_mean.3 0.503766225
67   7  NDVI_mean.3 0.120794820
68   8  NDVI_mean.3 0.777808416
69   9  NDVI_mean.3 0.755741184
70  10  NDVI_mean.3 0.058089687
71   1    NDVI_sd.3 0.009048781
72   2    NDVI_sd.3 0.029528930
73   3    NDVI_sd.3 0.098454753
74   4    NDVI_sd.3 0.089512544
75   5    NDVI_sd.3 0.241257647
76   6    NDVI_sd.3 0.114466677
77   7    NDVI_sd.3 0.013347437
78   8    NDVI_sd.3 0.066441491
79   9    NDVI_sd.3 0.065787691
80  10    NDVI_sd.3 0.013351357

So far this image shows how the plot is being produced. As you can see both NDVI_mean and NDVI_sd are used but this should not be the case. NDVI_sd should be used to produce geom_errorbar

@PoGibas, I have updated the question to show you the data. Thanks for your help — GCGM
– GCGM, Commented Oct 30, 2017 at 12:39
My mistake, that is a code of an older version that is not useful anymore since the data structure changed. Maybe I should remove it but I included it to show what I was trying to do before — GCGM
– GCGM, Commented Oct 30, 2017 at 12:41

pogibas · Accepted Answer · 2017-10-30 12:50:33Z

2

Code:

# Transform data
# Here we make table with three columns (ID Mean SD)
pd <- reshape2::dcast(NDVIdf_forplot, ID ~ statistic, value.var = "value")

# Plot data using ggplot2
library(ggplot2)
ggplot(pd, aes(ID, NDVI_mean)) +
    geom_point() +
    geom_line() +
    geom_errorbar(aes(ymin = NDVI_mean - NDVI_sd,
                      ymax = NDVI_mean + NDVI_sd))

Result plot:

answered Oct 30, 2017 at 12:50

pogibas

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3 Comments

GCGM Over a year ago

Thanks for your help. What if I want to plot on the Y axes the values of NDVI_mean, on the x axes the NDVI_mean.1, NDVI_mean.2 etc. and then one line for each ID (1 to 10)

pogibas Over a year ago

@GCGM I can't image what kind of figure is that

GCGM Over a year ago

Let me give you more details about my data. I have 10 images (multi-temporal dataset). For each image, I am deriving an index and then extracting the value of this index at my observation locations (10 points). What I want to produce is a graph where the value of that index is on the Y axes, the image date (image1, image2, etc) is on the X axes. So I would have one line for each observation (point). In my data, NDVI_mean is related to NDVI_sd (meaning those are one image), NDVI_mean.1 and NDVI_sd.1 are another image and so on

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