CODEWITHSUNDEEP
rggplot2
sieste
sieste

Reputation: 9027

2d density plot in orthographic projection in ggplot2

I get artifacts when plotting 2d density estimates in an orthographic projection. The problem is that the contour lines don't wrap around at the date line. Can this be done in ggplot2?

library(tidyverse)

# points on a map, longitude between -180 and 180
df = data_frame(lon=c(rnorm(100, -180, 50), 
                      rnorm(100, 180, 50)), 
                lat=rnorm(200, 60, 10)) %>% 
     filter(lon > -180, lon < 180)

# 2d density, orthographic projection
ggplot(data=df) +     
  coord_map('ortho') + 
  geom_point(aes(x=lon, y=lat)) + 
  stat_density2d(aes(x=lon, y=lat))

ggplot2 artifact in 2d density plot with orthographic projection

Upvotes: 2

Views: 239

Answers (1)

MrSmithGoesToWashington
MrSmithGoesToWashington

Reputation: 1076

Not sure that it is exactly what you are looking for : 

m <- mapproject(df$lon, df$lat, projection="orthographic", parameters=NULL, 
orientation=NULL)


ggplot(data=as.data.frame(cbind(m$x, m$y))) +     
  geom_point(aes(x=V1, y=V2)) + 
  geom_density2d(aes(x=V1, y=V2))

Upvotes: 2

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