scatterpie shape changes with the map from ggmap

[smallfishcui]

Hi,

I have been using the scatterpie package with ggmap package, aiming to show the genetic admixture on the map, here is my code:
library(tidyverse)
library(ggplot2)
library(ggmap)
library(scatterpie)
register_google(key = "xxxxx", write = TRUE)
d<-read.table("/Users/cuiwang/Desktop/map/Phmap.txt", header=TRUE)
a<-get_googlemap(center = c(mean(d$lon), mean(d$lat)), zoom = 1)
a<- ggmap(a)
a + geom_scatterpie(aes(x=long, y=lat,r=2), data=d, cols=c("Usnat","Usland","Med","AU","CN","EU"), color="#252728", alpha=1)

However, I got a picture with the pie chart skewed, as if it is also projected in the same way of the map. Is there any solution for this?

[kfuku52]

I came across a similar problem in combining scatterpie with ggtree + cowplot. The orange pie charts in the middle were generated by scatterpie but its aspect ratio cannot be easily adjusted. I would appreciate it if anybody could tell me a solution to force the pie charts perfect circle.

[Kamouyiaraki]

Hi I'm here with the same issue, hoping someone will see this to offer some insight!

[PGmajev]

This is also true when using geom_sf() and coord_sf()

[martinpastoors]

I have a similar issue trying to plot proportions on a map. This is using coord_quickmap(xlim=xlim, ylim=ylim):

If I use coord_equal, the problem disappears:

[madelynore]

hi! I have this same issue. Has anyone figured out a solution to this problem?

[GuangchuangYu]

use +coord_equal().

[madelynore]

Thanks, coord_equal() did not work for me, because I'm working maps plotted with WGS84 coordinate system and I get this error:

Coordinate system already present. Adding new coordinate system, which will replace the existing one.

But I did figure out a workaround, by projecting everything into NAD83, and that solved the problem