How to show lines when using ylim()?

I’m generating a plot with this code:

BPL2.0.5op <- subset(ambiental2021, dependencia=="BPL2.sala" & tipo.control=="NV")
BPL2.0.5op <- BPL2.0.5op[!is.na(BPL2.0.5op[,"part.0.5"]),]
BPL2.0.5op$punto <- naturalsort::naturalfactor(paste("Punto", BPL2.0.5op$punto, sep="."))

ggplot(BPL2.0.5op, 
       aes(x=fecha, y=part.0.5, group = punto, fill = punto)) +
  geom_point(aes(colour = punto), size = 1.5) +
  geom_line(aes(colour = punto), linetype = 1, size = 1) +
  theme(plot.title = element_text(size = 20, face = "bold")) +
  ggtitle("PARTÍCULAS DE 0,5 micras SALA BPL2") +
  ylab("Partículas 0,5 micras/m3") +
  xlab("fecha del control") +
  geom_hline(yintercept = 3520000, colour = "red", size = 1, linetype = 6) +
  scale_x_date(breaks = unique(BPL2.0.5op$fecha), labels = date_format("%d/%m/%Y")) +
  theme(axis.text.x = element_text(angle = 45, hjust = 1, size = 7), legend.position = "none") +
  facet_wrap(~ punto, ncol = 5, strip.position = "left")

And I get this type of graph:

Due to "Punto.17" peaks I lose resolution in the rest of the data. Mi intention is to add a "ylim()" argument to place a limit in the y axis. I used this code:

BPL2.0.5op <- subset(ambiental2021, dependencia=="BPL2.sala" & tipo.control=="NV")
BPL2.0.5op <- BPL2.0.5op[!is.na(BPL2.0.5op[,"part.0.5"]),]
BPL2.0.5op$punto <- naturalsort::naturalfactor(paste("Punto", BPL2.0.5op$punto, sep="."))

ggplot(BPL2.0.5op, 
       aes(x=fecha, y=part.0.5, group = punto, fill = punto)) +
  geom_point(aes(colour = punto), size = 1.5) +
  geom_line(aes(colour = punto), linetype = 1, size = 1) +
  theme(plot.title = element_text(size = 20, face = "bold")) +
  ggtitle("PARTÍCULAS DE 0,5 micras SALA BPL2") +
  ylab("Partículas 0,5 micras/m3") +
  ylim(0,4000000) +
  xlab("fecha del control") +
  geom_hline(yintercept = 3520000, colour = "red", size = 1, linetype = 6) +
  scale_x_date(breaks = unique(BPL2.0.5op$fecha), labels = date_format("%d/%m/%Y")) +
  theme(axis.text.x = element_text(angle = 45, hjust = 1, size = 7), legend.position = "none") +
  facet_wrap(~ punto, ncol = 5, strip.position = "left")

And I get this graph:

It’s seems as if there are no data… I would like the line to go up even though the point is far from the specified ylim(). I’d like a graph like this:

Please, could you show me how to do it?

>Solution :

library(ggplot2)
ggplot(data.frame(a = 1:10, b = c(1:6,4:1)), aes(x = a, y = b)) +
  geom_point() +
  geom_line() +
  coord_cartesian(ylim = c(1,4))

Will create the following "zoomed in" plot: