Adding a geom_point at the maximum of a stacked geom_col plot - coloured by a variable outcome

Question

I have some data which looks like:

# A tibble: 50 x 11
       V1     V2      V3     V4      V5      V6      V7      V8   GRP    ID OUTCOME
    <dbl>  <dbl>   <dbl>  <dbl>   <dbl>   <dbl>   <dbl>   <dbl> <int> <int>   <dbl>
 1  0.667  0.539  0.373  -0.774  0.197  -0.0816 -0.0835  0.189      1   166       1
 2 -0.436 -0.592 -0.686  -0.364 -0.0200 -0.0360  0.0285 -0.147      1    61       1
 3 -0.631 -0.573 -0.705  -0.287 -0.0507  0.0474  0.0182 -0.0702     1    54       1
 4  0.418  0.731  0.500   0.262 -0.0979  0.0353  0.0450  0.0156     1   240       0
 5  1.03   0.281 -0.0649 -0.670  0.223   0.138   0.0336  0.162      1   179       1
 6 -0.200  0.312  0.492   0.398 -0.0372 -0.0175  0.0101  0.0322     1   272       0
 7 -0.595 -0.549 -0.606  -0.308 -0.0358 -0.0281 -0.0478 -0.0832     1    76       0
 8 -0.289 -0.854 -1.01    0.169 -0.0207 -0.0149 -0.0742 -0.162      1    87       1
 9  0.608  0.392  0.478   0.223 -0.0372 -0.0495  0.0101  0.0479     1   224       1
10  0.707  0.595  0.496   0.615 -0.0372 -0.0209 -0.149   0.0682     1   164       1

I can plot the data using:

df %>% 
  arrange(OUTCOME) %>% 
  tibble() %>% 
  pivot_longer(cols = c(V1:V8)) %>% 
  setNames(c("GRP", "ID", "OUTCOME", "name", "value")) %>% # not sure why but the column name for OUTCOME was changing too - OUTCOME[,"outcome"] so I had to add a "setNames()" 
  ggplot(aes(x = ID, y = value, fill = name)) + 
  geom_col(width = 1, alpha = 0.9)

Where I want to arrange by OUTCOME and then plot such that the OUTCOME = 0 comes first and the OUTCOME = 1 comes second in the plot.

i.e. the x-axis corresponds to ID's and therefore I want the first 1:26 observations (which are 0 - OUTCOME) observations at the begining and the 27:50 ( which are 1 - OUTCOME) observation at the end of the plot.

In order to make this more clear in the plot I want to add a geom_vline(xintercept = 26) to the plot (which currently does not seem to do anything). Secondly, I want to add a geom_point at the tip of each of the geom_cols which are coloured according to the OUTCOME variable - so each stacked geom_col will have a point at the top.

Data:

df <- structure(list(V1 = c(0.666589915752411, -0.436222612857819, 
-0.631442725658417, 0.418105125427246, 1.03165137767792, -0.19955663383007, 
-0.595063030719757, -0.289468944072723, 0.608067691326141, 0.707050204277039, 
-0.352968633174896, -0.348733305931091, -0.734579741954803, -0.407550632953644, 
0.382651209831238, 0.317887604236603, 0.682134985923767, -1.3781418800354, 
-0.399168610572815, -0.718308925628662, 0.867228746414185, 0.679950773715973, 
0.839851379394531, -0.76373964548111, -1.42656266689301, -0.609997689723969, 
-0.385522603988647, 0.439238548278809, -0.456471681594849, -0.280009210109711, 
0.469753742218018, 0.318808495998383, -0.541835129261017, 0.842987537384033, 
0.452548682689667, 0.535462975502014, -0.364355206489563, -1.42656266689301, 
0.630698442459106, -0.44173675775528, -0.643441200256348, 0.685096621513367, 
1.14054381847382, 0.370130002498627, -0.619462072849274, -0.845775902271271, 
0.548840582370758, -0.477323114871979, -0.324755012989044, -0.781804263591766
), V2 = c(0.539071500301361, -0.59157657623291, -0.572662830352783, 
0.730981111526489, 0.281135410070419, 0.311570674180984, -0.549109578132629, 
-0.853675782680511, 0.392016798257828, 0.595141530036926, -0.566748976707458, 
0.478970289230347, -0.689719200134277, -0.291370570659637, 0.328506886959076, 
-1.00046491622925, 0.607915163040161, 0.167531609535217, -0.268897891044617, 
-0.669840693473816, 0.352877289056778, 0.335686177015305, 0.4686459004879, 
-0.120377041399479, 0.178255885839462, 0.242509573698044, 0.127220243215561, 
0.723466992378235, 0.169776439666748, 0.311570674180984, 0.241861879825592, 
-0.565791606903076, -0.596093893051147, 0.352877289056778, 0.755794286727905, 
0.237963885068893, -0.610303223133087, 0.178255885839462, 0.604371428489685, 
-0.566528797149658, -0.665839433670044, 0.572437882423401, -0.361080080270767, 
0.698914647102356, -0.539785265922546, 0.217821598052979, 0.808691143989563, 
0.50318056344986, -0.623627364635468, -0.344621360301971), V3 = c(0.373223125934601, 
-0.686219215393066, -0.705432772636414, 0.500304698944092, -0.0648666396737099, 
0.491708755493164, -0.60560667514801, -1.00564706325531, 0.477529734373093, 
0.496099144220352, -0.680513858795166, -0.289659559726715, -0.865037560462952, 
-0.3294717669487, 0.313058227300644, -0.659056186676025, 0.355539441108704, 
0.356298297643661, -0.742002785205841, -0.782470107078552, 0.462770104408264, 
0.524555385112762, 0.507511615753174, -0.400415688753128, 0.38832151889801, 
0.54375559091568, 0.348951697349548, 0.423646926879883, -0.22981920838356, 
0.472731471061707, 0.31219682097435, -0.381594121456146, -0.723009943962097, 
0.391745924949646, 0.414667755365372, 0.31219682097435, -0.779489040374756, 
0.38832151889801, 0.480808824300766, -0.666897296905518, -0.755469918251038, 
0.401484251022339, -0.543907880783081, 0.344876348972321, -0.528214573860168, 
-0.269392281770706, 0.56480598449707, 0.621908187866211, -0.531825602054596, 
-0.434289932250977), V4 = c(-0.773811459541321, -0.363897234201431, 
-0.287408024072647, 0.261809468269348, -0.670326471328735, 0.397776305675507, 
-0.307681560516357, 0.168681144714355, 0.223264053463936, 0.614758968353271, 
-0.338626772165298, -0.846252083778381, 0.11482846736908, -0.345179617404938, 
-1.05273842811584, -0.350423514842987, 0.196808382868767, 0.00778263807296753, 
0.189556911587715, 0.123728767037392, 0.583511531352997, 0.52887761592865, 
0.522512197494507, -0.343501180410385, 0.257596492767334, 0.581979811191559, 
-0.991406679153442, -0.863794207572937, -0.758265018463135, 0.374924182891846, 
-1.05103802680969, -0.504420638084412, 0.00401294603943825, 0.335065960884094, 
-0.823703289031982, -1.05103802680969, -0.353600144386292, 0.257596492767334, 
0.229928761720657, -0.338579297065735, -0.257122099399567, -0.802706837654114, 
0.196976840496063, -0.947062849998474, -0.328546792268753, -0.37180632352829, 
0.473592817783356, 0.396025836467743, -0.382713079452515, -0.403718531131744
), V5 = c(0.197130978107452, -0.0200146716088057, -0.0507026240229607, 
-0.0978699624538422, 0.222558438777924, -0.0371929332613945, 
-0.0357776693999767, -0.0207225400954485, -0.0371929332613945, 
-0.0371929332613945, -0.0357776693999767, -0.102090179920197, 
0.032932948321104, -0.0899124220013618, -0.102090179920197, 0.0611645467579365, 
0.0739013180136681, -0.0371929332613945, -0.0207225400954485, 
0.0266784615814686, -0.0371929332613945, -0.0371929332613945, 
-0.0978699624538422, -0.0507026240229607, -0.0371929332613945, 
-0.0371929332613945, -0.102090179920197, 0.222558438777924, -0.102090179920197, 
-0.0371929332613945, -0.102090179920197, -0.0442905239760876, 
-0.0356474928557873, -0.0371929332613945, 0.197130978107452, 
-0.102090179920197, -0.0507026240229607, -0.0371929332613945, 
0.0739013180136681, -0.0357776693999767, 0.0674190372228622, 
0.222558438777924, -0.0356474928557873, 0.197130978107452, -0.0357776693999767, 
0.193563550710678, 0.0484738424420357, 0.0484738424420357, -0.0357776693999767, 
0.0674190372228622), V6 = c(-0.0815747752785683, -0.0359503589570522, 
0.0473587699234486, 0.0353398211300373, 0.137635827064514, -0.017513670027256, 
-0.0280688628554344, -0.0148527026176453, -0.0495327338576317, 
-0.0209453999996185, -0.0280688628554344, -0.0714860409498215, 
0.0438234098255634, 0.120613776147366, -0.0714860409498215, -0.0342447310686111, 
0.0836121588945389, -0.0538526326417923, -0.0134977530688047, 
-0.0259735006839037, -0.017513670027256, -0.017513670027256, 
0.0353398211300373, 0.0394904688000679, -0.0380047224462032, 
-0.0380047224462032, -0.0495327338576317, 0.174676224589348, 
-0.0758059397339821, -0.0380047224462032, -0.0495327338576317, 
-0.0714860409498215, 0.0473587699234486, -0.017513670027256, 
-0.103528082370758, -0.0495327338576317, 0.0473587699234486, 
-0.0380047224462032, 0.0894022956490517, -0.0280688628554344, 
0.0527884140610695, 0.174676224589348, 0.0250600017607212, -0.103528082370758, 
-0.0280688628554344, -0.0359503589570522, -0.0529874339699745, 
-0.073478490114212, -0.0263632386922836, 0.0527884140610695), 
    V7 = c(-0.0834691673517227, 0.0285118855535984, 0.0181918852031231, 
    0.0450421050190926, 0.0335643924772739, 0.0101256892085075, 
    -0.0478062480688095, -0.0741845071315765, 0.0101256892085075, 
    -0.148965746164322, -0.0173042453825474, 0.0335643924772739, 
    0.0111529966816306, 0.0335643924772739, -0.241482585668564, 
    0.0323374196887016, 0.0374831557273865, 0.00208079349249601, 
    0.0306694488972425, -0.0391291491687298, 0.0101256892085075, 
    0.0101256892085075, 0.0450421050190926, 0.0188414938747883, 
    0.00208079349249601, 0.0101256892085075, -0.0643396899104118, 
    0.0936737284064293, 0.0335643924772739, 0.0101256892085075, 
    -0.0643396899104118, 0.0323374196887016, 0.0168080646544695, 
    0.0101256892085075, 0.110289998352528, -0.0643396899104118, 
    0.0285118855535984, 0.00208079349249601, 0.0450421050190926, 
    -0.0593610778450966, 0.016591826453805, 0.110289998352528, 
    0.0382283963263035, -0.241482585668564, -0.0384819433093071, 
    0.0229429267346859, 0.0101256892085075, -0.193015351891518, 
    -0.0816542878746986, 0.0229429267346859), V8 = c(0.188536351546645, 
    -0.14695412479341, -0.0702244397252798, 0.015599824488163, 
    0.162356040906161, 0.0322057278826833, -0.0832092929631472, 
    -0.162452442571521, 0.0479177413508296, 0.0682498225942254, 
    0.153729286044836, -0.243203143589199, 0.149779425002635, 
    -0.242116670124233, 0.109018758870661, -0.142883030232042, 
    -0.245007876306772, -0.0900559583678842, -0.247359684668481, 
    0.148495792876929, -0.0406780429184437, 0.00872406736016273, 
    0.138334958814085, -0.0638183308765292, -0.00990268588066101, 
    -0.0324675692245364, -0.114242037758231, -0.0935285966843367, 
    0.0216120602563024, 0.0322057278826833, 0.0343138063326478, 
    -0.0388489956967533, 0.0989119447767735, -0.0688016824424267, 
    0.166093233972788, -0.0274974387139082, 0.0373926516622305, 
    -0.00990268588066101, 0.140418875962496, -0.115373022854328, 
    -0.0672494322061539, 0.0669955778867006, 0.0579314436763525, 
    -0.194228617474437, -0.13398567494005, 0.117101473733783, 
    0.0771859539672732, 0.150191807188094, -0.1857496839948, 
    0.0725541273131967), GRP = c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 
    1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 
    1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 
    1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L), ID = c(166L, 
    61L, 54L, 240L, 179L, 272L, 76L, 87L, 224L, 164L, 13L, 125L, 
    14L, 41L, 147L, 64L, 33L, 260L, 95L, 10L, 219L, 234L, 243L, 
    53L, 261L, 279L, 123L, 177L, 127L, 269L, 142L, 63L, 18L, 
    214L, 168L, 141L, 20L, 263L, 191L, 75L, 3L, 182L, 31L, 171L, 
    74L, 170L, 249L, 154L, 67L, 4L), OUTCOME = c(1, 1, 1, 0, 
    1, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 
    0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 1, 1, 1, 0, 1, 
    1, 1, 0, 1, 1, 1, 1, 0)), class = "data.frame", row.names = c(NA, 
-50L))

EDIT:

(Excuse my poor MS Paint skills) - I was hoping for something like the following - where there are geom_points coloured at the begining (corresponding to 0) and then geom_points at the end (corresponding to 1). One point for each geom_col. (The geom_points do not need to lie on the same line as in the MS Paint version - I am happy also if they sit on top of each geom_col).

Answer 1

Understanding the biological problem really helped. How about ordering the individuals by value first and then plotting the outcome as the point?

df %>% 
  arrange(OUTCOME) %>% 
  tibble() %>% 
  pivot_longer(cols = c(V1:V8)) %>%
  ggplot(aes(x = reorder(factor(ID,unique(ID)),value, sum), y = value)) + 
  geom_point(aes(y = 3, color = as.factor(OUTCOME))) +
  scale_color_manual(values = c("red","black"), labels = c("Dead","Alive")) + 
  geom_col(aes(fill = name),width = 1, alpha = 0.9) + labs(x = "ID", color = "Outcome") + 
  theme(axis.text.x=element_blank(),
        axis.ticks.x=element_blank())