R / ggplot2 —逐面，以錯誤的順序繪制

Question

我試圖繪制一些時間序列數據，並按天對其進行分析。 我毫不費力地管理這些方面，但無法理解為什么每天的x軸順序不正確。 也就是說，不是從0:00開始到23:59結束，而是從22:00開始並在22:00結束。 任何幫助，不勝感激：

#Convert Datetime column to R POSIXct
original_data$Date<-as.POSIXct(x = original_data$Date, format = "%m/%d/%Y %H:%M")

#Set reference values to numeric
original_data$Reference<-as.numeric(original_data$Reference)

calibration_plot<-ggplot(original_data, aes(Date, Reference)) +
facet_wrap(~DOY, scales = "free") + xlab("Time (hours)") + 
geom_point()+     ylab(expression(Radiation ~ (W ~ m^{-2}))) + 
scale_x_datetime(labels = date_format("%H")) + ggtitle("Calibration 
Plots") + theme_bw() + theme(axis.text=element_text(size=12), 
axis.title=element_text(size=12,face="bold"), title = 
element_text(size=10, face = "bold"))


Date    DOY Reference
11/7/2016 0:01  312 -0.0137
11/7/2016 0:06  312 -0.01525
11/7/2016 0:11  312 -0.01325
11/7/2016 0:16  312 -0.01235
11/7/2016 0:21  312 -0.0119
11/7/2016 0:26  312 -0.0112
11/7/2016 0:31  312 -0.0109
11/7/2016 0:36  312 -0.0112
11/7/2016 0:41  312 -0.0105
11/7/2016 0:46  312 -0.00865
11/7/2016 0:51  312 -0.00875
11/7/2016 0:56  312 -0.0081
11/7/2016 1:01  312 -0.00885
11/7/2016 1:06  312 -0.00775
11/7/2016 1:11  312 -0.0086
11/7/2016 1:16  312 -0.0085
11/7/2016 1:21  312 -0.00915
11/7/2016 1:26  312 -0.0077
11/7/2016 1:31  312 -0.0114
11/7/2016 1:36  312 -0.0148
11/7/2016 1:41  312 -0.0121
11/7/2016 1:46  312 -0.012
11/7/2016 1:51  312 -0.0121
11/7/2016 1:56  312 -0.0086
11/7/2016 2:01  312 -0.00915
11/7/2016 2:06  312 -0.00945
11/7/2016 2:11  312 -0.0072
11/7/2016 2:16  312 -0.00485
11/7/2016 2:21  312 -0.006
11/7/2016 2:26  312 -0.00605
11/7/2016 2:31  312 -0.00685
11/7/2016 2:36  312 -0.00905
11/7/2016 2:41  312 -0.01085
11/7/2016 2:46  312 -0.0133
11/7/2016 2:51  312 -0.0118
11/7/2016 2:56  312 -0.01285
11/7/2016 3:01  312 -0.0125
11/7/2016 3:06  312 -0.0108
11/7/2016 3:11  312 -0.0114
11/7/2016 3:16  312 -0.01165
11/7/2016 3:21  312 -0.0117
11/7/2016 3:26  312 -0.0116
11/7/2016 3:31  312 -0.01155
11/7/2016 3:36  312 -0.01345
11/7/2016 3:41  312 -0.01375
11/7/2016 3:46  312 -0.01405
11/7/2016 3:51  312 -0.01195
11/7/2016 3:56  312 -0.012
11/7/2016 4:01  312 -0.0115
11/7/2016 4:06  312 -0.01215
11/7/2016 4:11  312 -0.01155
11/7/2016 4:16  312 -0.013
11/7/2016 4:21  312 -0.01135
11/7/2016 4:26  312 -0.01165
11/7/2016 4:31  312 -0.01125
11/7/2016 4:36  312 -0.01025
11/7/2016 4:41  312 -0.0106
11/7/2016 4:46  312 -0.0118
11/7/2016 4:51  312 -0.01045
11/7/2016 4:56  312 -0.0108
11/7/2016 5:01  312 -0.01315
11/7/2016 5:06  312 -0.01155
11/7/2016 5:11  312 -0.01195
11/7/2016 5:16  312 -0.01255
11/7/2016 5:21  312 -0.01145
11/7/2016 5:26  312 -0.011
11/7/2016 5:31  312 -0.0108
11/7/2016 5:36  312 -0.01115
11/7/2016 5:41  312 -0.0104
11/7/2016 5:46  312 -0.00325
11/7/2016 5:51  312 0.01585
11/7/2016 5:56  312 0.0383
11/7/2016 6:01  312 0.0541
11/7/2016 6:06  312 0.08845
11/7/2016 6:11  312 0.16495
11/7/2016 6:16  312 0.2525
11/7/2016 6:21  312 0.3453
11/7/2016 6:26  312 0.4411
11/7/2016 6:31  312 0.5581
11/7/2016 6:36  312 0.73945
11/7/2016 6:41  312 0.84045
11/7/2016 6:46  312 1.0619
11/7/2016 6:51  312 1.50535
11/7/2016 6:56  312 1.7774
11/7/2016 7:01  312 1.9699
11/7/2016 7:06  312 1.94915
11/7/2016 7:11  312 1.984
11/7/2016 7:16  312 2.17855
11/7/2016 7:21  312 2.5005
11/7/2016 7:26  312 2.35345
11/7/2016 7:31  312 2.43305
11/7/2016 7:36  312 2.63425
11/7/2016 7:41  312 3.16065
11/7/2016 7:46  312 3.34475
11/7/2016 7:51  312 3.2605
11/7/2016 7:56  312 3.3372
11/7/2016 8:01  312 3.3398
11/7/2016 8:06  312 3.43235
11/7/2016 8:11  312 3.8922
11/7/2016 8:16  312 4.359
11/7/2016 8:21  312 4.4112
11/7/2016 8:26  312 4.7168
11/7/2016 8:31  312 4.8878
11/7/2016 8:36  312 5.05045
11/7/2016 8:41  312 5.20745
11/7/2016 8:46  312 4.82285
11/7/2016 8:51  312 5.19705
11/7/2016 8:56  312 4.9623
11/7/2016 9:01  312 5.164
11/7/2016 9:06  312 5.85755
11/7/2016 9:11  312 5.91635
11/7/2016 9:16  312 6.20635
11/7/2016 9:21  312 6.3367
11/7/2016 9:26  312 6.4511
11/7/2016 9:31  312 6.5009
11/7/2016 9:36  312 6.55115
11/7/2016 9:41  312 6.77255
11/7/2016 9:46  312 6.73385
11/7/2016 9:51  312 6.739
11/7/2016 9:56  312 7.0979
11/7/2016 10:01 312 7.2608
11/7/2016 10:06 312 7.39525
11/7/2016 10:11 312 7.32865
11/7/2016 10:16 312 7.4016
11/7/2016 10:21 312 7.70725
11/7/2016 10:26 312 7.8645
11/7/2016 10:31 312 7.8682
11/7/2016 10:36 312 8.0161
11/7/2016 10:41 312 7.7934
11/7/2016 10:46 312 5.99495
11/7/2016 10:51 312 8.25685
11/7/2016 10:56 312 8.7265
11/7/2016 11:01 312 8.5505
11/7/2016 11:06 312 8.1372
11/7/2016 11:11 312 5.0642
11/7/2016 11:16 312 5.0355
11/7/2016 11:21 312 6.32535
11/7/2016 11:26 312 5.8676
11/7/2016 11:31 312 7.37175
11/7/2016 11:36 312 6.1949
11/7/2016 11:41 312 5.01225
11/7/2016 11:46 312 5.91725
11/7/2016 11:51 312 6.7572
11/7/2016 11:56 312 7.70375
11/7/2016 12:01 312 8.12815
11/7/2016 12:06 312 6.04805
11/7/2016 12:11 312 5.2638
11/7/2016 12:16 312 4.85
11/7/2016 12:21 312 4.2291
11/7/2016 12:26 312 4.2851
11/7/2016 12:31 312 4.99735
11/7/2016 12:36 312 4.7308
11/7/2016 12:41 312 5.2383
11/7/2016 12:46 312 6.9894
11/7/2016 12:51 312 6.8357
11/7/2016 12:56 312 9.124
11/7/2016 13:01 312 9.2875
11/7/2016 13:06 312 7.11615
11/7/2016 13:11 312 7.8034
11/7/2016 13:16 312 5.29235
11/7/2016 13:21 312 6.02785
11/7/2016 13:26 312 5.6154
11/7/2016 13:31 312 3.5963
11/7/2016 13:36 312 2.88325
11/7/2016 13:41 312 2.7976
11/7/2016 13:46 312 3.07845
11/7/2016 13:51 312 3.55455
11/7/2016 13:56 312 3.2716
11/7/2016 14:01 312 2.8856
11/7/2016 14:06 312 4.42685
11/7/2016 14:11 312 6.93045
11/7/2016 14:16 312 6.68565
11/7/2016 14:21 312 6.0181
11/7/2016 14:26 312 3.3964
11/7/2016 14:31 312 3.3697
11/7/2016 14:36 312 2.99275
11/7/2016 14:41 312 5.2926
11/7/2016 14:46 312 4.70665
11/7/2016 14:51 312 4.16065
11/7/2016 14:56 312 3.7451
11/7/2016 15:01 312 3.47665
11/7/2016 15:06 312 3.2893
11/7/2016 15:11 312 3.0863
11/7/2016 15:16 312 2.9122
11/7/2016 15:21 312 2.71525
11/7/2016 15:26 312 2.50645
11/7/2016 15:31 312 2.26005
11/7/2016 15:36 312 2.0562
11/7/2016 15:41 312 1.89285
11/7/2016 15:46 312 1.3635
11/7/2016 15:51 312 1.1739
11/7/2016 15:56 312 1.4291
11/7/2016 16:01 312 1.1776
11/7/2016 16:06 312 1.03155
11/7/2016 16:11 312 0.8916
11/7/2016 16:16 312 0.73225
11/7/2016 16:21 312 0.6009
11/7/2016 16:26 312 0.47795
11/7/2016 16:31 312 0.35235
11/7/2016 16:36 312 0.2142
11/7/2016 16:41 312 0.11565
11/7/2016 16:46 312 0.04355
11/7/2016 16:51 312 0.0127
11/7/2016 16:56 312 -0.00405
11/7/2016 17:01 312 -0.0198
11/7/2016 17:06 312 -0.02375
11/7/2016 17:11 312 -0.0219
11/7/2016 17:16 312 -0.01975
11/7/2016 17:21 312 -0.02105
11/7/2016 17:26 312 -0.02275
11/7/2016 17:31 312 -0.022
11/7/2016 17:36 312 -0.02135
11/7/2016 17:41 312 -0.02165
11/7/2016 17:46 312 -0.0232
11/7/2016 17:51 312 -0.01995
11/7/2016 17:56 312 -0.02085
11/7/2016 18:01 312 -0.0197
11/7/2016 18:06 312 -0.02185
11/7/2016 18:11 312 -0.0213
11/7/2016 18:16 312 -0.022
11/7/2016 18:21 312 -0.01915
11/7/2016 18:26 312 -0.0211
11/7/2016 18:31 312 -0.02025
11/7/2016 18:36 312 -0.0198
11/7/2016 18:41 312 -0.0205
11/7/2016 18:46 312 -0.0212
11/7/2016 18:51 312 -0.0212
11/7/2016 18:56 312 -0.0221
11/7/2016 19:01 312 -0.0209
11/7/2016 19:06 312 -0.0214
11/7/2016 19:11 312 -0.02025
11/7/2016 19:16 312 -0.02115
11/7/2016 19:21 312 -0.02205
11/7/2016 19:26 312 -0.0225
11/7/2016 19:31 312 -0.0216
11/7/2016 19:36 312 -0.0206
11/7/2016 19:41 312 -0.02145
11/7/2016 19:46 312 -0.0214
11/7/2016 19:51 312 -0.02115
11/7/2016 19:56 312 -0.021
11/7/2016 20:01 312 -0.02075
11/7/2016 20:06 312 -0.0224
11/7/2016 20:11 312 -0.02035
11/7/2016 20:16 312 -0.01915
11/7/2016 20:21 312 -0.02075
11/7/2016 20:26 312 -0.02095
11/7/2016 20:31 312 -0.0228
11/7/2016 20:36 312 -0.0207
11/7/2016 20:41 312 -0.0215
11/7/2016 20:46 312 -0.01995
11/7/2016 20:51 312 -0.0209
11/7/2016 20:56 312 -0.0202
11/7/2016 21:01 312 -0.02125
11/7/2016 21:06 312 -0.02045
11/7/2016 21:11 312 -0.02345
11/7/2016 21:16 312 -0.02325
11/7/2016 21:21 312 -0.02195
11/7/2016 21:26 312 -0.02065
11/7/2016 21:31 312 -0.01935
11/7/2016 21:36 312 -0.01475
11/7/2016 21:41 312 -0.0172
11/7/2016 21:46 312 -0.01635
11/7/2016 21:51 312 -0.01495
11/7/2016 21:56 312 -0.0145
11/7/2016 22:01 312 -0.0177
11/7/2016 22:06 312 -0.01585
11/7/2016 22:11 312 -0.0134
11/7/2016 22:16 312 -0.01355
11/7/2016 22:21 312 -0.01435
11/7/2016 22:26 312 -0.0134
11/7/2016 22:31 312 -0.0157
11/7/2016 22:36 312 -0.01535
11/7/2016 22:41 312 -0.0139
11/7/2016 22:46 312 -0.01495
11/7/2016 22:51 312 -0.01585
11/7/2016 22:56 312 -0.01735
11/7/2016 23:01 312 -0.01475
11/7/2016 23:06 312 -0.0165
11/7/2016 23:11 312 -0.0157
11/7/2016 23:16 312 -0.0223
11/7/2016 23:21 312 -0.0214
11/7/2016 23:26 312 -0.02155
11/7/2016 23:31 312 -0.02245
11/7/2016 23:36 312 -0.0223
11/7/2016 23:41 312 -0.02315
11/7/2016 23:46 312 -0.0204
11/7/2016 23:51 312 -0.01915
11/7/2016 23:56 312 -0.018
11/8/2016 0:01  313 -0.01895
11/8/2016 0:06  313 -0.0195
11/8/2016 0:11  313 -0.0152
11/8/2016 0:16  313 -0.0157
11/8/2016 0:21  313 -0.0177
11/8/2016 0:26  313 -0.0179
11/8/2016 0:31  313 -0.0185
11/8/2016 0:36  313 -0.0164
11/8/2016 0:41  313 -0.0145
11/8/2016 0:46  313 -0.0158
11/8/2016 0:51  313 -0.01295
11/8/2016 0:56  313 -0.0149
11/8/2016 1:01  313 -0.014
11/8/2016 1:06  313 -0.01505
11/8/2016 1:11  313 -0.01795
11/8/2016 1:16  313 -0.01375
11/8/2016 1:21  313 -0.0066
11/8/2016 1:26  313 -0.00835
11/8/2016 1:31  313 -0.00785
11/8/2016 1:36  313 -0.0082
11/8/2016 1:41  313 -0.0108
11/8/2016 1:46  313 -0.01275
11/8/2016 1:51  313 -0.01515
11/8/2016 1:56  313 -0.01505
11/8/2016 2:01  313 -0.01805
11/8/2016 2:06  313 -0.01875
11/8/2016 2:11  313 -0.01955
11/8/2016 2:16  313 -0.0201
11/8/2016 2:21  313 -0.0183
11/8/2016 2:26  313 -0.01715
11/8/2016 2:31  313 -0.0169
11/8/2016 2:36  313 -0.0139
11/8/2016 2:41  313 -0.0145
11/8/2016 2:46  313 -0.0162
11/8/2016 2:51  313 -0.01275
11/8/2016 2:56  313 -0.01285
11/8/2016 3:01  313 -0.01605
11/8/2016 3:06  313 -0.0133
11/8/2016 3:11  313 -0.00905
11/8/2016 3:16  313 -0.0149
11/8/2016 3:21  313 -0.01395
11/8/2016 3:26  313 -0.01115
11/8/2016 3:31  313 -0.0108
11/8/2016 3:36  313 -0.01015
11/8/2016 3:41  313 -0.00805
11/8/2016 3:46  313 -0.00735
11/8/2016 3:51  313 -0.00615
11/8/2016 3:56  313 -0.0055
11/8/2016 4:01  313 -0.0138
11/8/2016 4:06  313 -0.01405
11/8/2016 4:11  313 -0.01755
11/8/2016 4:16  313 -0.0181
11/8/2016 4:21  313 -0.01675
11/8/2016 4:26  313 -0.0165
11/8/2016 4:31  313 -0.01455
11/8/2016 4:36  313 -0.01425
11/8/2016 4:41  313 -0.0146
11/8/2016 4:46  313 -0.0152
11/8/2016 4:51  313 -0.0125
11/8/2016 4:56  313 -0.0117
11/8/2016 5:01  313 -0.01215
11/8/2016 5:06  313 -0.0125
11/8/2016 5:11  313 -0.0132
11/8/2016 5:16  313 -0.0126
11/8/2016 5:21  313 -0.0135
11/8/2016 5:26  313 -0.01165
11/8/2016 5:31  313 -0.00775
11/8/2016 5:36  313 -0.00695
11/8/2016 5:41  313 -0.00385
11/8/2016 5:46  313 -0.00235
11/8/2016 5:51  313 0.0028
11/8/2016 5:56  313 0.01585
11/8/2016 6:01  313 0.03635
11/8/2016 6:06  313 0.07065
11/8/2016 6:11  313 0.1311
11/8/2016 6:16  313 0.21305
11/8/2016 6:21  313 0.32055
11/8/2016 6:26  313 0.43565
11/8/2016 6:31  313 0.5715
11/8/2016 6:36  313 0.7204
11/8/2016 6:41  313 0.8756
11/8/2016 6:46  313 1.0433
11/8/2016 6:51  313 1.2124
11/8/2016 6:56  313 1.3829
11/8/2016 7:01  313 1.5636
11/8/2016 7:06  313 1.7513
11/8/2016 7:11  313 1.9341
11/8/2016 7:16  313 2.11025
11/8/2016 7:21  313 2.28195
11/8/2016 7:26  313 2.46095
11/8/2016 7:31  313 2.64895
11/8/2016 7:36  313 2.83475
11/8/2016 7:41  313 3.01725
11/8/2016 7:46  313 3.19545
11/8/2016 7:51  313 3.37045
11/8/2016 7:56  313 3.5479
11/8/2016 8:01  313 3.71555
11/8/2016 8:06  313 3.89685
11/8/2016 8:11  313 4.0722
11/8/2016 8:16  313 4.24365
11/8/2016 8:21  313 4.421
11/8/2016 8:26  313 4.6007
11/8/2016 8:31  313 4.7579
11/8/2016 8:36  313 4.9085
11/8/2016 8:41  313 5.0742
11/8/2016 8:46  313 5.2702
11/8/2016 8:51  313 5.43175
11/8/2016 8:56  313 5.5679
11/8/2016 9:01  313 5.70595
11/8/2016 9:06  313 5.8536
11/8/2016 9:11  313 6.00405
11/8/2016 9:16  313 6.14975
11/8/2016 9:21  313 6.28225
11/8/2016 9:26  313 6.3957
11/8/2016 9:31  313 6.49145
11/8/2016 9:36  313 6.61005
11/8/2016 9:41  313 6.7059
11/8/2016 9:46  313 6.803
11/8/2016 9:51  313 6.9047
11/8/2016 9:56  313 6.99005
11/8/2016 10:01 313 7.10665
11/8/2016 10:06 313 7.1775
11/8/2016 10:11 313 7.24965
11/8/2016 10:16 313 7.32285
11/8/2016 10:21 313 7.40145
11/8/2016 10:26 313 7.4465
11/8/2016 10:31 313 7.48625
11/8/2016 10:36 313 7.5403
11/8/2016 10:41 313 7.56665
11/8/2016 10:46 313 7.6129
11/8/2016 10:51 313 7.6587
11/8/2016 10:56 313 7.65805
11/8/2016 11:01 313 7.69065
11/8/2016 11:06 313 7.69305
11/8/2016 11:11 313 7.75695
11/8/2016 11:16 313 7.7813
11/8/2016 11:21 313 7.807
11/8/2016 11:26 313 7.84605
11/8/2016 11:31 313 7.86405
11/8/2016 11:36 313 7.86835
11/8/2016 11:41 313 7.71245
11/8/2016 11:46 313 7.81435
11/8/2016 11:51 313 7.78805
11/8/2016 11:56 313 7.7583
11/8/2016 12:01 313 7.70065
11/8/2016 12:06 313 7.6603
11/8/2016 12:11 313 7.622
11/8/2016 12:16 313 7.56315
11/8/2016 12:21 313 7.4049
11/8/2016 12:26 313 7.4034
11/8/2016 12:31 313 7.278
11/8/2016 12:36 313 7.3192
11/8/2016 12:41 313 7.19265
11/8/2016 12:46 313 7.4927
11/8/2016 12:51 313 7.54555
11/8/2016 12:56 313 7.69435
11/8/2016 13:01 313 6.95105
11/8/2016 13:06 313 6.26065
11/8/2016 13:11 313 6.90735
11/8/2016 13:16 313 6.4603
11/8/2016 13:21 313 5.69755
11/8/2016 13:26 313 5.30295
11/8/2016 13:31 313 5.993
11/8/2016 13:36 313 6.24425
11/8/2016 13:41 313 5.89575
11/8/2016 13:46 313 6.3803
11/8/2016 13:51 313 6.17455
11/8/2016 13:56 313 5.6555
11/8/2016 14:01 313 5.0811
11/8/2016 14:06 313 3.33805
11/8/2016 14:11 313 3.131
11/8/2016 14:16 313 3.87235
11/8/2016 14:21 313 4.3724
11/8/2016 14:26 313 4.6554
11/8/2016 14:31 313 4.7956
11/8/2016 14:36 313 3.41335
11/8/2016 14:41 313 3.11155
11/8/2016 14:46 313 3.9269
11/8/2016 14:51 313 2.8726
11/8/2016 14:56 313 2.68095
11/8/2016 15:01 313 2.98235
11/8/2016 15:06 313 3.1635
11/8/2016 15:11 313 3.09815
11/8/2016 15:16 313 2.89455
11/8/2016 15:21 313 2.7253
11/8/2016 15:26 313 2.52735
11/8/2016 15:31 313 2.30685
11/8/2016 15:36 313 1.9471
11/8/2016 15:41 313 1.76245
11/8/2016 15:46 313 1.7001
11/8/2016 15:51 313 1.509
11/8/2016 15:56 313 1.31435
11/8/2016 16:01 313 1.1337
11/8/2016 16:06 313 0.9801
11/8/2016 16:11 313 0.83105
11/8/2016 16:16 313 0.67265
11/8/2016 16:21 313 0.53225
11/8/2016 16:26 313 0.41065
11/8/2016 16:31 313 0.3211
11/8/2016 16:36 313 0.2437
11/8/2016 16:41 313 0.1663
11/8/2016 16:46 313 0.08585
11/8/2016 16:51 313 0.02745
11/8/2016 16:56 313 -0.001
11/8/2016 17:01 313 -0.0124
11/8/2016 17:06 313 -0.01965
11/8/2016 17:11 313 -0.0209
11/8/2016 17:16 313 -0.0219
11/8/2016 17:21 313 -0.02165
11/8/2016 17:26 313 -0.0221
11/8/2016 17:31 313 -0.021
11/8/2016 17:36 313 -0.02155
11/8/2016 17:41 313 -0.0211
11/8/2016 17:46 313 -0.0214
11/8/2016 17:51 313 -0.0222
11/8/2016 17:56 313 -0.0209
11/8/2016 18:01 313 -0.0217
11/8/2016 18:06 313 -0.0225
11/8/2016 18:11 313 -0.0215
11/8/2016 18:16 313 -0.02195
11/8/2016 18:21 313 -0.0217
11/8/2016 18:26 313 -0.02125
11/8/2016 18:31 313 -0.02095
11/8/2016 18:36 313 -0.0218
11/8/2016 18:41 313 -0.02165
11/8/2016 18:46 313 -0.02235
11/8/2016 18:51 313 -0.0214
11/8/2016 18:56 313 -0.0211
11/8/2016 19:01 313 -0.02195
11/8/2016 19:06 313 -0.02135
11/8/2016 19:11 313 -0.02195
11/8/2016 19:16 313 -0.0222
11/8/2016 19:21 313 -0.0215
11/8/2016 19:26 313 -0.02155
11/8/2016 19:31 313 -0.0225
11/8/2016 19:36 313 -0.02205
11/8/2016 19:41 313 -0.0209
11/8/2016 19:46 313 -0.0222
11/8/2016 19:51 313 -0.02205
11/8/2016 19:56 313 -0.02255
11/8/2016 20:01 313 -0.0224
11/8/2016 20:06 313 -0.0232
11/8/2016 20:11 313 -0.0234
11/8/2016 20:16 313 -0.02285
11/8/2016 20:21 313 -0.0224
11/8/2016 20:26 313 -0.0242
11/8/2016 20:31 313 -0.023
11/8/2016 20:36 313 -0.02055
11/8/2016 20:41 313 -0.01945
11/8/2016 20:46 313 -0.0173
11/8/2016 20:51 313 -0.01545
11/8/2016 20:56 313 -0.0199
11/8/2016 21:01 313 -0.0195
11/8/2016 21:06 313 -0.0178
11/8/2016 21:11 313 -0.019
11/8/2016 21:16 313 -0.0182
11/8/2016 21:21 313 -0.01805
11/8/2016 21:26 313 -0.01845
11/8/2016 21:31 313 -0.018
11/8/2016 21:36 313 -0.01645
11/8/2016 21:41 313 -0.0161
11/8/2016 21:46 313 -0.0163
11/8/2016 21:51 313 -0.0157
11/8/2016 21:56 313 -0.0152
11/8/2016 22:01 313 -0.01885
11/8/2016 22:06 313 -0.01865
11/8/2016 22:11 313 -0.0191
11/8/2016 22:16 313 -0.02055
11/8/2016 22:21 313 -0.023
11/8/2016 22:26 313 -0.0216
11/8/2016 22:31 313 -0.0174
11/8/2016 22:36 313 -0.0206
11/8/2016 22:41 313 -0.0196
11/8/2016 22:46 313 -0.0185
11/8/2016 22:51 313 -0.02025
11/8/2016 22:56 313 -0.0187
11/8/2016 23:01 313 -0.0197
11/8/2016 23:06 313 -0.01915
11/8/2016 23:11 313 -0.0192
11/8/2016 23:16 313 -0.01875
11/8/2016 23:21 313 -0.0168
11/8/2016 23:26 313 -0.01535
11/8/2016 23:31 313 -0.01515
11/8/2016 23:36 313 -0.0156
11/8/2016 23:41 313 -0.01725
11/8/2016 23:46 313 -0.0175
11/8/2016 23:51 313 -0.0183
11/8/2016 23:56 313 -0.01815
11/9/2016 0:01  314 -0.02115
11/9/2016 0:06  314 -0.01925
11/9/2016 0:11  314 -0.01605
11/9/2016 0:16  314 -0.01725
11/9/2016 0:21  314 -0.01875
11/9/2016 0:26  314 -0.01695
11/9/2016 0:31  314 -0.01585
11/9/2016 0:36  314 -0.0156
11/9/2016 0:41  314 -0.0158
11/9/2016 0:46  314 -0.01735
11/9/2016 0:51  314 -0.02115
11/9/2016 0:56  314 -0.0203
11/9/2016 1:01  314 -0.01595
11/9/2016 1:06  314 -0.0162
11/9/2016 1:11  314 -0.01845
11/9/2016 1:16  314 -0.01935
11/9/2016 1:21  314 -0.01705
11/9/2016 1:26  314 -0.01725
11/9/2016 1:31  314 -0.0183
11/9/2016 1:36  314 -0.01585
11/9/2016 1:41  314 -0.01665
11/9/2016 1:46  314 -0.0179
11/9/2016 1:51  314 -0.02015
11/9/2016 1:56  314 -0.01765
11/9/2016 2:01  314 -0.016
11/9/2016 2:06  314 -0.01575
11/9/2016 2:11  314 -0.01795
11/9/2016 2:16  314 -0.0155
11/9/2016 2:21  314 -0.01745
11/9/2016 2:26  314 -0.0203
11/9/2016 2:31  314 -0.0185
11/9/2016 2:36  314 -0.0186
11/9/2016 2:41  314 -0.01935
11/9/2016 2:46  314 -0.0184
11/9/2016 2:51  314 -0.01735
11/9/2016 2:56  314 -0.01695
11/9/2016 3:01  314 -0.01775
11/9/2016 3:06  314 -0.019
11/9/2016 3:11  314 -0.0167
11/9/2016 3:16  314 -0.015
11/9/2016 3:21  314 -0.01565
11/9/2016 3:26  314 -0.0153
11/9/2016 3:31  314 -0.0167
11/9/2016 3:36  314 -0.0172
11/9/2016 3:41  314 -0.0183
11/9/2016 3:46  314 -0.0197
11/9/2016 3:51  314 -0.01745
11/9/2016 3:56  314 -0.019
11/9/2016 4:01  314 -0.0172
11/9/2016 4:06  314 -0.0192
11/9/2016 4:11  314 -0.018
11/9/2016 4:16  314 -0.016
11/9/2016 4:21  314 -0.01565
11/9/2016 4:26  314 -0.01495
11/9/2016 4:31  314 -0.0141
11/9/2016 4:36  314 -0.0165
11/9/2016 4:41  314 -0.0181
11/9/2016 4:46  314 -0.0142
11/9/2016 4:51  314 -0.014
11/9/2016 4:56  314 -0.0154
11/9/2016 5:01  314 -0.01815
11/9/2016 5:06  314 -0.01695
11/9/2016 5:11  314 -0.01535
11/9/2016 5:16  314 -0.0173
11/9/2016 5:21  314 -0.0168
11/9/2016 5:26  314 -0.01705
11/9/2016 5:31  314 -0.0131
11/9/2016 5:36  314 -0.01255
11/9/2016 5:41  314 -0.011
11/9/2016 5:46  314 -0.0074
11/9/2016 5:51  314 -0.0033
11/9/2016 5:56  314 0.0092
11/9/2016 6:01  314 0.02835
11/9/2016 6:06  314 0.05945
11/9/2016 6:11  314 0.11275
11/9/2016 6:16  314 0.19305
11/9/2016 6:21  314 0.29155
11/9/2016 6:26  314 0.41715
11/9/2016 6:31  314 0.5569
11/9/2016 6:36  314 0.7058
11/9/2016 6:41  314 0.85515
11/9/2016 6:46  314 1.0122
11/9/2016 6:51  314 1.17105
11/9/2016 6:56  314 1.3468
11/9/2016 7:01  314 1.533
11/9/2016 7:06  314 1.72655
11/9/2016 7:11  314 1.8999
11/9/2016 7:16  314 2.0892
11/9/2016 7:21  314 2.27335
11/9/2016 7:26  314 2.45275
11/9/2016 7:31  314 2.6254
11/9/2016 7:36  314 2.80495
11/9/2016 7:41  314 2.9698
11/9/2016 7:46  314 3.14485
11/9/2016 7:51  314 3.33695
11/9/2016 7:56  314 3.5185
11/9/2016 8:01  314 3.72455
11/9/2016 8:06  314 3.91035
11/9/2016 8:11  314 4.0785
11/9/2016 8:16  314 4.2559
11/9/2016 8:21  314 4.4217
11/9/2016 8:26  314 4.5722
11/9/2016 8:31  314 4.7556
11/9/2016 8:36  314 4.9501
11/9/2016 8:41  314 5.11165
11/9/2016 8:46  314 5.2733
11/9/2016 8:51  314 5.4304
11/9/2016 8:56  314 5.56685
11/9/2016 9:01  314 5.703
11/9/2016 9:06  314 5.8769
11/9/2016 9:11  314 6.01635
11/9/2016 9:16  314 6.111
11/9/2016 9:21  314 6.24235
11/9/2016 9:26  314 6.3809
11/9/2016 9:31  314 6.5062
11/9/2016 9:36  314 6.64785
11/9/2016 9:41  314 6.75385
11/9/2016 9:46  314 6.84935
11/9/2016 9:51  314 6.93285
11/9/2016 9:56  314 7.02905
11/9/2016 10:01 314 7.11505
11/9/2016 10:06 314 7.2036
11/9/2016 10:11 314 7.2851
11/9/2016 10:16 314 7.33835
11/9/2016 10:21 314 7.44855
11/9/2016 10:26 314 7.4837
11/9/2016 10:31 314 7.53375
11/9/2016 10:36 314 7.62295
11/9/2016 10:41 314 7.66075
11/9/2016 10:46 314 7.68485
11/9/2016 10:51 314 7.7384
11/9/2016 10:56 314 7.7615
11/9/2016 11:01 314 7.82885
11/9/2016 11:06 314 7.8675
11/9/2016 11:11 314 7.91915
11/9/2016 11:16 314 7.94695
11/9/2016 11:21 314 7.93695
11/9/2016 11:26 314 7.9442
11/9/2016 11:31 314 7.9382
11/9/2016 11:36 314 7.9218
11/9/2016 11:41 314 7.92835
11/9/2016 11:46 314 7.9046
11/9/2016 11:51 314 7.8732
11/9/2016 11:56 314 7.83255
11/9/2016 12:01 314 7.803
11/9/2016 12:06 314 7.7647
11/9/2016 12:11 314 7.7232
11/9/2016 12:16 314 7.6825
11/9/2016 12:21 314 7.6342
11/9/2016 12:26 314 7.5411
11/9/2016 12:31 314 7.45375
11/9/2016 12:36 314 7.38675
11/9/2016 12:41 314 7.18185
11/9/2016 12:46 314 7.13925
11/9/2016 12:51 314 7.135
11/9/2016 12:56 314 6.98295
11/9/2016 13:01 314 6.89455
11/9/2016 13:06 314 6.8586
11/9/2016 13:11 314 6.7578
11/9/2016 13:16 314 6.65955
11/9/2016 13:21 314 6.57115
11/9/2016 13:26 314 6.442
11/9/2016 13:31 314 6.2897
11/9/2016 13:36 314 6.1718
11/9/2016 13:41 314 6.0275
11/9/2016 13:46 314 5.88025
11/9/2016 13:51 314 5.73785
11/9/2016 13:56 314 5.5934
11/9/2016 14:01 314 5.4494
11/9/2016 14:06 314 5.1863
11/9/2016 14:11 314 4.98255
11/9/2016 14:16 314 4.8496
11/9/2016 14:21 314 4.8176
11/9/2016 14:26 314 4.6013
11/9/2016 14:31 314 4.2561
11/9/2016 14:36 314 3.96345
11/9/2016 14:41 314 3.9824
11/9/2016 14:46 314 3.9432
11/9/2016 14:51 314 3.7544
11/9/2016 14:56 314 3.4839
11/9/2016 15:01 314 2.7597
11/9/2016 15:06 314 2.4419
11/9/2016 15:11 314 2.64675
11/9/2016 15:16 314 2.45525
11/9/2016 15:21 314 2.4179
11/9/2016 15:26 314 2.3876
11/9/2016 15:31 314 2.23465
11/9/2016 15:36 314 2.07505
11/9/2016 15:41 314 1.79335
11/9/2016 15:46 314 1.415
11/9/2016 15:51 314 1.25875
11/9/2016 15:56 314 0.99305
11/9/2016 16:01 314 0.716
11/9/2016 16:06 314 0.51725
11/9/2016 16:11 314 0.43155
11/9/2016 16:16 314 0.42175
11/9/2016 16:21 314 0.52755
11/9/2016 16:26 314 0.4067
11/9/2016 16:31 314 0.2853
11/9/2016 16:36 314 0.18875
11/9/2016 16:41 314 0.1121
11/9/2016 16:46 314 0.0422
11/9/2016 16:51 314 0.0087
11/9/2016 16:56 314 -0.01395
11/9/2016 17:01 314 -0.0253
11/9/2016 17:06 314 -0.03095
11/9/2016 17:11 314 -0.03115
11/9/2016 17:16 314 -0.0322
11/9/2016 17:21 314 -0.03055
11/9/2016 17:26 314 -0.02585
11/9/2016 17:31 314 -0.02525
11/9/2016 17:36 314 -0.0207
11/9/2016 17:41 314 -0.01985
11/9/2016 17:46 314 -0.0202
11/9/2016 17:51 314 -0.0216
11/9/2016 17:56 314 -0.02065
11/9/2016 18:01 314 -0.02215
11/9/2016 18:06 314 -0.02005
11/9/2016 18:11 314 -0.017
11/9/2016 18:16 314 -0.01985
11/9/2016 18:21 314 -0.02015
11/9/2016 18:26 314 -0.02005
11/9/2016 18:31 314 -0.01875
11/9/2016 18:36 314 -0.019
11/9/2016 18:41 314 -0.01875
11/9/2016 18:46 314 -0.0196
11/9/2016 18:51 314 -0.0123
11/9/2016 18:56 314 -0.01185
11/9/2016 19:01 314 -0.01485
11/9/2016 19:06 314 -0.0187
11/9/2016 19:11 314 -0.02015
11/9/2016 19:16 314 -0.01935
11/9/2016 19:21 314 -0.0197
11/9/2016 19:26 314 -0.01885
11/9/2016 19:31 314 -0.0218
11/9/2016 19:36 314 -0.0169
11/9/2016 19:41 314 -0.01205
11/9/2016 19:46 314 -0.01245
11/9/2016 19:51 314 -0.0112
11/9/2016 19:56 314 -0.01655
11/9/2016 20:01 314 -0.0185
11/9/2016 20:06 314 -0.0204
11/9/2016 20:11 314 -0.0227
11/9/2016 20:16 314 -0.02115
11/9/2016 20:21 314 -0.01345
11/9/2016 20:26 314 -0.0135
11/9/2016 20:31 314 -0.0191
11/9/2016 20:36 314 -0.0172
11/9/2016 20:41 314 -0.0136
11/9/2016 20:46 314 -0.0129
11/9/2016 20:51 314 -0.0176
11/9/2016 20:56 314 -0.01285
11/9/2016 21:01 314 -0.0138
11/9/2016 21:06 314 -0.0179
11/9/2016 21:11 314 -0.0193
11/9/2016 21:16 314 -0.02365
11/9/2016 21:21 314 -0.02045
11/9/2016 21:26 314 -0.0218
11/9/2016 21:31 314 -0.0215
11/9/2016 21:36 314 -0.02105
11/9/2016 21:41 314 -0.0184
11/9/2016 21:46 314 -0.01795
11/9/2016 21:51 314 -0.01945
11/9/2016 21:56 314 -0.01865
11/9/2016 22:01 314 -0.01425
11/9/2016 22:06 314 -0.0125
11/9/2016 22:11 314 -0.0093
11/9/2016 22:16 314 -0.01355
11/9/2016 22:21 314 -0.01235
11/9/2016 22:26 314 -0.01205
11/9/2016 22:31 314 -0.01225
11/9/2016 22:36 314 -0.0138
11/9/2016 22:41 314 -0.01255
11/9/2016 22:46 314 -0.01655
11/9/2016 22:51 314 -0.01695
11/9/2016 22:56 314 -0.01605
11/9/2016 23:01 314 -0.018
11/9/2016 23:06 314 -0.01165
11/9/2016 23:11 314 -0.00995
11/9/2016 23:16 314 -0.0181
11/9/2016 23:21 314 -0.0137
11/9/2016 23:26 314 -0.014
11/9/2016 23:31 314 -0.02185
11/9/2016 23:36 314 -0.0238
11/9/2016 23:41 314 -0.02165
11/9/2016 23:46 314 -0.02095
11/9/2016 23:51 314 -0.01925
11/9/2016 23:56 314 -0.0201

Answer 1

TL; DR：這看起來像是時區問題。 當您將日期轉換為POSIXct時，默認時區是您的本地時區。 但是，當您在ggplot運行date_format() ，日期將在繪制之前轉換為GMT，因此，時間都會因GMT與本地時區之間的時差而發生偏移。 為了獲得正確的小時數，您可以在date_format顯式設置所需的時區，也可以在將Date轉換為POSIXct時將時區顯式設置為GMT。

---

在處理ggplot代碼之前，讓我們看一下您的數據。 下面，在將Date轉換為POSIXct之前，我先介紹了您的數據：

head(original_data)
str(original_data)

  Date DOY Reference 1 11/7/2016 0:01 312 -0.01370 2 11/7/2016 0:06 312 -0.01525 3 11/7/2016 0:11 312 -0.01325 4 11/7/2016 0:16 312 -0.01235 5 11/7/2016 0:21 312 -0.01190 6 11/7/2016 0:26 312 -0.01120 'data.frame': 864 obs. of 3 variables: $ Date : chr "11/7/2016 0:01" "11/7/2016 0:06" "11/7/2016 0:11" "11/7/2016 0:16" ... $ DOY : int 312 312 312 312 312 312 312 312 312 312 ... $ Reference: num -0.0137 -0.0152 -0.0132 -0.0123 -0.0119 ... 

現在，以兩種不同的方式將Date轉換為POSIXct：首先，不設置時區，然后將時區設置為GMT。 請注意，盡管字面時間字符串相同，但Date1在我的本地時區（美國太平洋時區）中，而Date2在GMT中。

original_data$Date1 <- as.POSIXct(x = original_data$Date, format = "%m/%d/%Y %H:%M")
original_data$Date2 <- as.POSIXct(x = original_data$Date, format = "%m/%d/%Y %H:%M", tz="GMT")

head(original_data$Date1) 

 [1] "2016-11-07 00:01:00 PST" "2016-11-07 00:06:00 PST" "2016-11-07 00:11:00 PST" "2016-11-07 00:16:00 PST" [5] "2016-11-07 00:21:00 PST" "2016-11-07 00:26:00 PST" 

head(original_data$Date2)

 [1] "2016-11-07 00:01:00 GMT" "2016-11-07 00:06:00 GMT" "2016-11-07 00:11:00 GMT" "2016-11-07 00:16:00 GMT" [5] "2016-11-07 00:21:00 GMT" "2016-11-07 00:26:00 GMT" 

這是date_format函數的代碼。 請注意，默認的tz （時區）設置為UTC ，與GMT相同。 因此date_format時間值從數據的時區轉換為GMT：

date_format

 function (format = "%Y-%m-%d", tz = "UTC") { function(x) format(x, format, tz = tz) } 

現在為ggplot ：首先，我們將使用Date1 。 在下面的示例中，請注意，當我們使用默認日期格式時，小時數是正確的。 但是，當我們scale_x_datetime不指定時區的情況下使用scale_x_datetime時，ggplot似乎正在從我的本地時區（美國太平洋時區）轉移到GMT，這是8小時后。 但是，當我在date_format()指定“ America / Los_Angeles”時區時，將獲得所需的小時值。

# Create plot with Date1, but without scale_x_datetime
p = ggplot(original_data, aes(Date1, Reference)) +
  facet_wrap(~ DOY, scales="free_x") + 
  xlab("Time (hours)") + 
  geom_point() +     
  ylab(expression(Radiation ~ (W ~ m^{-2}))) +
  ggtitle("Calibration Plots") + 
  theme_bw() + 
  theme(axis.title=element_text(size=12,face="bold"), 
        title = element_text(size=9, face = "bold"))

p + scale_x_datetime(date_breaks = "3 hours") + 
  ggtitle("Default date formatting") + 
  theme(axis.text.x=element_text(size=9, angle=-90, , vjust=0.5))
p + scale_x_datetime(date_breaks = "3 hours", labels=date_format("%H")) + 
  ggtitle('date_format("%H")')
p + scale_x_datetime(date_breaks = "3 hours", labels=date_format("%H", tz="America/Los_Angeles")) +
  ggtitle('date_format("%H", tz="America/Los_Angeles")')

另一方面，如果我們使用已經設置為GMT時區的Date2 ，則無需在date_format()指定時區：

# Create plot with Date2, but without scale_x_datetime
p = ggplot(original_data, aes(Date2, Reference)) +
  facet_wrap(~ DOY, scales="free_x") + 
  xlab("Time (hours)") + 
  geom_point() +     
  ylab(expression(Radiation ~ (W ~ m^{-2}))) +
  ggtitle("Calibration Plots") + 
  theme_bw() + 
  theme(axis.title=element_text(size=12,face="bold"), 
        title = element_text(size=9, face = "bold"))

p + scale_x_datetime(date_breaks = "3 hours") + 
  ggtitle("Default date formatting") + 
  theme(axis.text.x=element_text(size=9, angle=-90, , vjust=0.5))
p + scale_x_datetime(date_breaks = "3 hours", labels=date_format("%H")) + 
  ggtitle('date_format("%H")')
p + scale_x_datetime(date_breaks = "3 hours", labels=date_format("%H", tz="GMT")) +
  ggtitle('date_format("%H", tz="GMT")')