I tried doing the following:
ggplot(geography) + geom_sf(aes(fill=rate, color = NULL))
but that didn't get rid of the border lines.
Peter
Without a reproducible example it is difficult to know exactly what you are looking for. However, I will take a guess that your are looking for a way to suppress the lines marking boundaries between different polygons (regions), e.g., suppress the lines showing country borders on a map of the world. If that is so then here is a solution.
Use lwd = 0 in the geom_sf call.
Example (you might need to download the developmental version of ggplot2)
# devtools::install_github("tidyverse/ggplot2")
library(ggplot2)
library(maps)
library(maptools)
library(rgeos)
library(sf)
world1 <- sf::st_as_sf(map('world', plot = FALSE, fill = TRUE))
with_boundary <-
ggplot() +
geom_sf(data = world1, mapping = aes(fill = ID)) +
theme(legend.position = "none") +
ggtitle("With Country Boundaries")
without_boundary <-
ggplot() +
geom_sf(data = world1, mapping = aes(fill = ID), lwd = 0) +
theme(legend.position = "none") +
ggtitle("Without Country Boundaries")
来源：https://stackoverflow.com/questions/47720329/how-can-i-remove-border-lines-when-using-geom-sf