How can I change the thickness of a specific line and/or add shape in a multi-line plot?

I have a data called molten.data below. I have this code which plots the lines I want, but I need to change the thickness of one specific line (G11F:G11M) to make it look thicker compared to other lines or preferably add shape to the data point in that line. How can we do it?

molten.data

G11F:G11M

code I have:

ggplot(molten.data, aes(variable, value,group= key.related,colour=key.related)) +
geom_line() +
geom_point()


data:

molten.data<- structure(list(key.related = c("G11F:G11F", "G11F:G11F", "G11F:G11F",
"G11F:G11M", "G11F:G11F", "G11F:G11M", "G11F:AOGC-02-0079", "G11F:G11F",
"G11F:G11M"), variable = structure(c(1L, 2L, 3L, 3L, 4L, 4L,
4L, 5L, 5L), .Label = c("IBS_2_samples", "IBS_4_samples", "IBS_8_samples",
"IBS_16_samples", "IBS_32_samples"), class = "factor"), value = c(0.533,
1.01, 1.11, 0.132, 1.22, 0.353, 0.0658, 1.33, 0.534)), .Names = c("key.related",
"variable", "value"), row.names = c(1L, 82L, 163L, 168L, 244L,
249L, 260L, 325L, 330L), class = "data.frame")


2 Answers
2

You can set up a column to note whether an observation should be highlighted, and map that to size, shape, linetype, etc.

You can do that with an ifelse:

ifelse

library(tidyverse)

molten.data %>%
mutate(hilite = ifelse(key.related == "G11F:G11M", 2, 1))
#> key.related variable value hilite
#> 1 G11F:G11F IBS_2_samples 0.5330 1
#> 2 G11F:G11F IBS_4_samples 1.0100 1
#> 3 G11F:G11F IBS_8_samples 1.1100 1
#> 4 G11F:G11M IBS_8_samples 0.1320 2
#> 5 G11F:G11F IBS_16_samples 1.2200 1
#> 6 G11F:G11M IBS_16_samples 0.3530 2
#> 7 G11F:AOGC-02-0079 IBS_16_samples 0.0658 1
#> 8 G11F:G11F IBS_32_samples 1.3300 1
#> 9 G11F:G11M IBS_32_samples 0.5340 2


My preference is to do it with factors. forcats::fct_other lets you pick levels to keep, and labels everything else as "Other". Imagine you have several keys you want to keep with their original names, and a whole lot of keys you want to lump into an "Other" category—it becomes pretty useful as the data gets more complicated.

forcats::fct_other

Then I pipe it into ggplot, using hilite to designate the highlighting. One way is with size; you can adjust the sizes to make it more dramatic, or get whatever sizes are appropriate:

ggplot

hilite

molten.data %>%
mutate(hilite = as.factor(key.related) %>% fct_other(keep = c("G11F:G11M"), other_level = "Other keys")) %>%
ggplot(aes(x = variable, y = value, color = key.related, group = key.related, size = hilite)) +
geom_line() +
geom_point(size = 2) +
scale_size_manual(values = c("G11F:G11M" = 1.5, "Other keys" = 0.5), guide = F)


Or keeping size uniform but changing shapes. Here I set up the shape values so the non-highlighted points get a normal circle point and the highlighted points get triangles.

molten.data %>%
mutate(hilite = as.factor(key.related) %>% fct_other(keep = c("G11F:G11M"), other_level = "Other keys")) %>%
ggplot(aes(x = variable, y = value, color = key.related, group = key.related)) +
geom_line() +
geom_point(aes(shape = hilite), size = 2) +
scale_shape_manual(values = c("G11F:G11M" = 17, "Other keys" = 16), guide = F)


Created on 2018-07-01 by the reprex package (v0.2.0).

Based on what you need you can keep or remove size or linetype as shown below -

l <- ifelse(molten.data$key.related == 'G11F:G11M', 1, 2)
ltyp <- ifelse(molten.data$key.related == 'G11F:G11M', 'longdash', '“dotted”')

ggplot(data=molten.data, aes(x=variable, y=value, group= key.related, colour=key.related)) +
geom_line(aes( linetype = ltyp , size = l )) +
geom_point(aes( size = l ))


l

linetype

geom_point

l

size

ltyp

geom_point

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