plotting timeseries with ggplot with legends

Question

I have 2 time series, which one is Actual and another the forecast. i want to plot them on same graph to show their differences with legends ( Actual to be "solid" and Forecast to be "dashed"). As im trying to use ggplo function as script below, only one time series is shown, while 2 legends ( as attached picture)! Thanks for attention.

legs=c("Actual" = "solid", "Forecast" = "dashed")
ggplot() +
  geom_line(data = df_COVIX_ts, aes(x = t, y = Actual, color = "Actual")) +
  geom_line(data = df_COVIX_prediction_sGARCH, aes(x = t, y = Forecast, color = "Forecast",linetype="dashed")) +
  
  scale_x_date(date_labels = "%Y-%m-%d", limits = c(min(t), max(t))) +
  ggtitle("VIX - Actual Vs. Prediction (GARCH)") +
  theme(plot.title = element_text(hjust = 0.5, size = 9)) +
  labs(x = "", y = "VIX") +
  guides(fill = guide_legend(title = "Title")) +
  scale_linetype_manual(values = legs) +
  scale_color_manual(name = "", values = c("Actual" = "black", "Forecast" ="black"))

Answer 1

ggplot2 works well with long data frames. By first pivoting the actual and forecast values into a long structure, you can map the variable with these measurement names to a linetype aesthetic.

library(tidyverse)

glimpse(df)
#> Rows: 200
#> Columns: 3
#> $ date     <date> 2020-02-01, 2020-02-08, 2020-02-15, 2020-02-22, 2020-02-29, …
#> $ actual   <dbl> 3.288741, 4.428592, 1.062242, 2.182198, 3.516459, 6.052417, 5…
#> $ forecast <dbl> 4.169825, 4.505264, 3.698598, 5.805117, 4.910112, 9.936979, 4…

df %>%
  pivot_longer(-date) %>%
  ggplot(aes(x = date, y = value, linetype = name)) +
  geom_line() +
  scale_x_date(date_labels = '%Y-%m-%d') +
  labs(linetype = '', x = '')

Data

df <- structure(list(date = structure(c(18293, 18300, 18307, 18314, 
                                        18321, 18328, 18335, 18342, 18349, 18356, 18363, 18370, 18377, 
                                        18384, 18391, 18398, 18405, 18412, 18419, 18426, 18433, 18440, 
                                        18447, 18454, 18461, 18468, 18475, 18482, 18489, 18496, 18503, 
                                        18510, 18517, 18524, 18531, 18538, 18545, 18552, 18559, 18566, 
                                        18573, 18580, 18587, 18594, 18601, 18608, 18615, 18622, 18629, 
                                        18636, 18643, 18650, 18657, 18664, 18671, 18678, 18685, 18692, 
                                        18699, 18706, 18713, 18720, 18727, 18734, 18741, 18748, 18755, 
                                        18762, 18769, 18776, 18783, 18790, 18797, 18804, 18811, 18818, 
                                        18825, 18832, 18839, 18846, 18853, 18860, 18867, 18874, 18881, 
                                        18888, 18895, 18902, 18909, 18916, 18923, 18930, 18937, 18944, 
                                        18951, 18958, 18965, 18972, 18979, 18986, 18993, 19000, 19007, 
                                        19014, 19021, 19028, 19035, 19042, 19049, 19056, 19063, 19070, 
                                        19077, 19084, 19091, 19098, 19105, 19112, 19119, 19126, 19133, 
                                        19140, 19147, 19154, 19161, 19168, 19175, 19182, 19189, 19196, 
                                        19203, 19210, 19217, 19224, 19231, 19238, 19245, 19252, 19259, 
                                        19266, 19273, 19280, 19287, 19294, 19301, 19308, 19315, 19322, 
                                        19329, 19336, 19343, 19350, 19357, 19364, 19371, 19378, 19385, 
                                        19392, 19399, 19406, 19413, 19420, 19427, 19434, 19441, 19448, 
                                        19455, 19462, 19469, 19476, 19483, 19490, 19497, 19504, 19511, 
                                        19518, 19525, 19532, 19539, 19546, 19553, 19560, 19567, 19574, 
                                        19581, 19588, 19595, 19602, 19609, 19616, 19623, 19630, 19637, 
                                        19644, 19651, 19658, 19665, 19672, 19679, 19686), class = "Date"), 
                     actual = c(3.28874065030508, 4.4285922274598, 1.06224207639793, 
                                2.18219770760681, 3.51645879226372, 6.05241746961732, 5.79611702128364, 
                                4.13234452035898, 3.38111266642933, 1.50281761091055, 1.42556812473176, 
                                2.48496180277605, 1.19097163407738, 4.99984428513707, 6.69143163730217, 
                                2.71063691016419, 1.12206950996106, 1.98279398073119, 8.13375839438498, 
                                4.41327208119987, 4.34748661301959, 2.57364490218226, 1.96491029930092, 
                                3.21420226037685, 6.87894697756316, 9.53814816440948, 3.33775053766952, 
                                4.04572492069243, 6.45358947480898, 4.85125895833075, 7.71729867373477, 
                                3.89058806744212, 7.44677179828588, 5.25369694043315, 6.99723067851833, 
                                1.23764852451844, 1.85804340573129, 4.93495911314066, 3.20421123194634, 
                                3.80202345498991, 4.59728668936361, 2.20377207592745, 1.71123553649349, 
                                7.15085833808143, 3.54856516018219, 0.439908553151525, 2.22810283918601, 
                                2.52543797405242, 3.72697424238729, 4.88527716653564, 4.95257428044565, 
                                4.24044745063398, 6.0837989635431, 4.58644123181828, 4.6627564481823, 
                                2.83625992914383, 2.35733511308702, 1.39942432392613, 3.06066932142494, 
                                7.23117133717794, 5.1165872418357, 2.98492856003888, 1.26060898372184, 
                                1.14770478034679, 2.14793765624062, 5.36193788608447, 0.760095250622055, 
                                4.8180757061164, 1.67570233859657, 4.75492269976045, 3.4732781673343, 
                                5.62642192460913, 1.38336562887383, 2.22909047975983, 4.18916612892439, 
                                4.23407279306309, 4.80449922527823, 4.69848009545694, 0.648620348836542, 
                                2.10217964562766, 9.79161306455318, 4.34507783699215, 3.28605287765656, 
                                3.27619753512109, 2.54849756971699, 3.64913316445642, 1.97649439415558, 
                                4.75004086963248, 5.89452279605083, 4.06815942287174, 5.46191155974912, 
                                3.17598747699571, 5.15929503245336, 5.70205132765433, 1.60802306613371, 
                                2.75412269646413, 6.99581375614331, 3.13471629117182, 6.20510248013667, 
                                4.36919724503688, 3.34471255414684, 3.11300440383322, 5.30929011441096, 
                                1.46662433681718, 5.64344817346343, 5.69323453199174, 1.850016719382, 
                                2.57247090492984, 4.20175748227793, 1.30578596379586, 4.15078792603889, 
                                7.11467567720884, 2.15971923715515, 5.40061300333779, 3.70121472000772, 
                                1.3617153406259, 5.51263400668972, 3.12589683373434, 1.09549827871575, 
                                6.4093757150203, 1.49379496940512, 1.05302911159218, 3.68975211480564, 
                                2.99026821623729, 4.30555984703391, 4.7946309831355, 4.80405783187878, 
                                2.31175208388313, 4.22796069322853, 2.57354577694459, 1.19693062225977, 
                                3.81924831940111, 4.26912831319176, 6.51161546099656, 1.08264442210734, 
                                3.00211535337831, 7.64123432672373, 2.69803396414478, 3.0876252287969, 
                                1.64093027385428, 10.9520904422579, 0.636647108258377, 4.6066342644438, 
                                5.03957339604486, 4.88858427288202, 6.70029787422672, 4.87579822429576, 
                                5.70388932441972, 1.16289987676769, 6.09353996105886, 2.16209642843071, 
                                5.74320425146561, 2.08156802093873, 2.24300448653446, 2.66976361887272, 
                                5.97083447317016, 3.84695325250366, 3.7594231842453, 3.38617878684922, 
                                1.88668690266653, 2.36107348490651, 6.65334068791418, 3.75371111166926, 
                                6.19565658169446, 1.85967966753591, 1.71153439664321, 4.94785249969116, 
                                3.94823800314345, 3.10487907824919, 3.28638926637272, 6.0333266812145, 
                                5.24212084819572, 1.61142946050173, 2.36199246287038, 2.48780112436943, 
                                4.23712578674802, 1.6571057101026, 6.81719110323871, 4.85683105832273, 
                                5.69374764879796, 4.56595331542098, 2.71591570075931, 2.59150077303684, 
                                7.11581725053756, 1.6658238685009, 3.57788145686773, 7.50839120336298, 
                                2.3318800202984, 2.94936493725179, 2.7027546593414, 2.39700955772009, 
                                2.87958209412425, 2.67661402223743, 3.89419446014874, 4.87023632133511, 
                                2.32855834531085, 3.45170366013234, 1.58687357218832, 3.83931639618774, 
                                3.37765595251538), forecast = c(4.1698247724348, 4.50526394911021, 
                                                                3.69859791711935, 5.80511741309413, 4.91011218921042, 9.93697854898073, 
                                                                4.54180883476536, 3.87773652428389, 6.05144754745353, 6.21865459270552, 
                                                                2.71263832348855, 2.04246351718433, 4.9614825282331, 3.64269608731646, 
                                                                6.18980570332805, 8.3468995581247, 4.73104409699238, 11.0968116451996, 
                                                                6.83854772564325, 4.2849862913275, 4.08276422790788, 6.4020457253604, 
                                                                2.7781907424399, 6.23872352473962, 8.82188754578991, 5.04043346975867, 
                                                                4.6884295997509, 5.16827932207786, 5.72437482762343, 4.64470500656282, 
                                                                2.27917425096252, 5.80676663808963, 3.2785827117899, 8.90703555940237, 
                                                                9.59670634477214, 6.78567382120192, 9.35304280174594, 4.79717345737545, 
                                                                8.05507265034085, 2.99737714088976, 7.27308146209495, 4.73676211374256, 
                                                                7.30329391613901, 2.43652408788639, 7.91631621476096, 7.00179391531402, 
                                                                4.89564803091592, 7.98961342949566, 3.98960524237949, 1.83041021882691, 
                                                                14.0243553061146, 2.91931709551672, 4.60822741067605, 5.67641513116577, 
                                                                5.42816179867222, 2.26694856325183, 6.23050438765815, 4.2355547355738, 
                                                                4.39875792607304, 6.92853999571364, 4.56785561606008, 4.9975540692599, 
                                                                1.80742582922693, 4.2667172098683, 9.01843062688821, 4.19681188195013, 
                                                                4.53006473264954, 3.45434053863443, 8.75924676382993, 8.2037837237412, 
                                                                13.3697553854309, 5.91862895498429, 3.64999080205973, 2.20889028572588, 
                                                                6.28455297871811, 3.81643928260327, 4.45333620166443, 5.67259489527364, 
                                                                3.19658317811276, 7.10009232772503, 3.48255878232722, 10.1725848725698, 
                                                                5.34842666331172, 5.56383800181514, 3.26803528283006, 6.0142175878763, 
                                                                4.45904170869608, 8.76536915520345, 8.51715950667011, 6.16930185708268, 
                                                                4.70138916953348, 5.28206148655482, 5.92728647122255, 4.29942635244725, 
                                                                9.49314870180486, 10.7936129536663, 4.64799951690488, 6.70237967278852, 
                                                                5.98724497482555, 5.23585740492705, 7.38057933701108, 12.3632564077007, 
                                                                12.341113200617, 7.03258485384277, 4.84242706012351, 6.17166439479491, 
                                                                5.65836227347138, 7.46120542691246, 8.4371731114912, 4.47460174584551, 
                                                                9.63507336518174, 6.2709342273401, 2.48339668024008, 5.58580071522955, 
                                                                10.1844759632255, 10.5469730831885, 8.21390106475101, 2.85448830173941, 
                                                                4.52380980233145, 7.13220415484461, 5.79357910731392, 5.1522671240697, 
                                                                6.39873116594009, 9.630743406872, 3.35813258452889, 3.70629511377323, 
                                                                5.31771655891862, 2.61309494337275, 7.14419954821106, 10.8188853784094, 
                                                                8.03754046693252, 5.80277070359749, 4.3074445116721, 2.51875990327741, 
                                                                5.34943351212739, 2.95020001266179, 5.75772580540749, 5.87313425181282, 
                                                                4.7583250163393, 11.2310061125872, 4.8709503376592, 8.1673460014618, 
                                                                5.12919595685114, 10.1854168540149, 7.13666644948573, 6.37704716945168, 
                                                                7.36792420543312, 4.9637030465638, 7.36448617132007, 3.80484260513138, 
                                                                6.5518513520329, 6.96477719204104, 6.28397625406823, 8.23569291343554, 
                                                                5.36775391599576, 3.74352810111954, 2.00064077908589, 4.40062275963743, 
                                                                5.92144847952075, 7.37049715145676, 6.9702459807258, 8.43800878188679, 
                                                                6.43853926551262, 4.59899879588672, 14.4402791967773, 2.86489152982389, 
                                                                5.26045088585811, 7.73356605836671, 5.40894504536202, 3.60114623868179, 
                                                                7.4875573786376, 2.65154597388059, 4.92143403055419, 4.95081834248318, 
                                                                4.42343093985504, 11.5488569892395, 8.36672282493584, 9.45131386782127, 
                                                                8.57443960804476, 6.15502316555192, 5.05377288267693, 3.38338452875799, 
                                                                4.6738214151808, 2.54023148382839, 9.02771870404468, 4.63263795820419, 
                                                                7.5327650597126, 3.24477778462022, 8.6162729910346, 8.23774939355695, 
                                                                4.90941719708473, 9.2421367798144, 5.05250178864963, 5.82968965786235, 
                                                                4.12554916715611, 6.27360841264592, 6.5083005079192, 8.46695419836787, 
                                                                3.45837903116391, 4.4821903498946)), class = c("tbl_df", 
                                                                                                               "tbl", "data.frame"), row.names = c(NA, -200L))