How to apply the coordinate limits to one layer only in ggplot?

Question

Data

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Problem

I have 2 datasets. The first one is the pos_df which contains the coordinates of vehicle motion as follows:

> head(pos_df)
  frames    ED_x      ED_y
1   1442 31367.9 -3103.045
2   1443 31367.9 -3103.045
3   1444 31367.9 -3103.043
4   1445 31367.9 -3103.041
5   1446 31367.9 -3103.038
6   1447 31367.9 -3103.034

I can plot it:

library(ggplot2)
ggplot() + 
  geom_path(data = pos_df, mapping = aes(ED_x, ED_y))

The second dataset is actually a svg image, Springfield.svg. I can read it using the svgparser package:

# remotes::install_github('coolbutuseless/svgparser')
library(svgparser)
df <- svgparser::read_svg("Springfield.svg", obj_type = 'data.frame') 

I can plot it as well:

ggplot() + 
 geom_path(data = df,
            aes(x, y,
                group = interaction(elem_idx, path_idx)),
            color = "grey50")  

But it is upside down. Zooming in to the section where pos_df is relevant and rotating the plot:

ggplot() + 
  geom_path(data = df,
            aes(x, y,
                group = interaction(elem_idx, path_idx)),
            color = "grey50") +
  coord_cartesian(xlim = c(30000, 44000),
                  ylim = c(5000, -7000))  

I want to now combine the two datasets. But when I do, the pos_df is also flipped:

ggplot() + 
  geom_path(data = df,
            aes(x, y,
                group = interaction(elem_idx, path_idx)),
            color = "grey50") +
  coord_cartesian(xlim = c(30000, 44000),
                  ylim = c(5000, -7000)) +
  geom_path(data = pos_df, mapping = aes(ED_x, ED_y), color = "red")+
  theme_bw()  

How can apply the coord limits to the df only?

Answer 1

One simple solution is to use -ED_y:

ggplot() + 
  geom_path(data = df,
            aes(x, y,
                group = interaction(elem_idx, path_idx)),
            color = "grey50") +
  coord_cartesian(xlim = c(30000, 44000),
                  ylim = c(5000, -7000)) +
  geom_path(data = pos_df, mapping = aes(ED_x, -ED_y), color = "red")+
  theme_bw()