geom_point not showing up on ggplot with geom_sf of rivers - r

Question

I am trying to build a map that contains a few points overlayed onto rivers. I am using code adapted from https://milospopovic.net/map-rivers-with-sf-and-ggplot2-in-r/, but I downloaded the North America map and substituted
st_polygon(list(cbind(
c(-84.9, -84.9, -84.0, -84.0, -84.9),
c(34.4, 35.05, 35.05, 34.4, 34.4)
))),
crs = crsLONGLAT)
to create my bounding box.
test.point <- data.frame("x"= -84.73405, "y"= 35.00988)
p <-
ggplot()+
geom_point(data= test.point, aes(x=x, y=y), color= "black", fill= "black") +
geom_sf(data=na_riv, aes(color=factor(ORD_FLOW), size=width)) +
coord_sf(crs = 4087,
xlim = c(bbox["xmin"], bbox["xmax"]),
ylim = c(bbox["ymin"], bbox["ymax"])) +
labs(x= "", subtitle="",
title="Rivers of the Southeast",
caption="©2022\nSource: ©World Wildlife Fund, Inc. (2006-2013)\n HydroSHEDS database http://www.hydrosheds.org") +
scale_color_manual(
name = "",
values = c('#081f6b', '#08306b', '#08519c', '#2171b5', '#4292c6', '#6baed6', '#9ecae1', '#c6dbef', '#deebf7')) +
scale_size(range=c(0, .3)) +
scale_alpha_manual(values=c("2"= 1, "3" = 1, "4" = 1, "5" = .7, "6" = .6, "7" = .4, "8" = .3, "9" = .2, "10" = .1)) +
theme_bw() +
theme(text = element_text(family = "georg"),
panel.background = element_blank(),
legend.background = element_blank(),
legend.position = "none",
panel.border = element_blank(),
panel.grid.minor = element_blank(),
panel.grid.major = element_blank(),
plot.title = element_text(size=40, color="#2171b5", hjust=0.5, vjust=0),
plot.subtitle = element_text(size=14, color="#ac63a0", hjust=0.5, vjust=0),
plot.caption = element_text(size=10, color="grey60", hjust=0.5, vjust=10),
legend.text = element_text(size=9, color="grey20"),
legend.title = element_text(size=10, color="grey20"),
strip.text = element_text(size=12),
plot.margin = unit(c(t=1, r=0, b=-1, l=-1),"lines"))
p
The above code yields a pretty map of all of the rivers but the point doesn't show up. :(

Answer 1

Here is one way to get around this. Basically you can convert the points you want to highlight a a simple feature geometry:
test.point <- data.frame(x = c(-84.73405, -84.6), y = c(35.00988, 34.6))
new_test.point <- st_sfc(st_multipoint(as.matrix(test.point)), crs = crsLONGLAT)
Then, I just filtered the data to have only the rivers present in the area of interested:
nariv = nariv %>% mutate(inter = as.integer(st_intersects(geometry, bbox)))
nariv_filt = nariv %>% filter(!is.na(inter))
And create the plot:
ggplot() +
geom_sf(data = nariv_filt, aes(color = factor(ORD_FLOW), size = width, alpha = width)) +
geom_sf(data = new_test.point, color="red", size=5)+
coord_sf(crs = prj, xlim = c(bb["xmin"], bb["xmax"]),ylim = c(bb["ymin"], bb["ymax"])) +
geom_point(data = test.point, aes(x=x, y=y), color="red", size=5)+
labs(y = "", subtitle = "", x = "", title = "Rivers of North and Central America") +
scale_color_manual(name = "",
values = c(
"#08306b", "#1c4680", "#305d94", "#4574a7",
"#5d8cb9", "#77a4cb", "#deebf7", "#deebf7", "#deebf7"
), drop = F) +
scale_alpha(range = c(0.3, 0.8)) +
scale_size(range = c(0, 3)) +
theme_minimal() +
theme(
text = element_text(family = "Montserrat"),
panel.background = element_blank(),
legend.background = element_blank(),
legend.position = "none",
panel.border = element_blank(),
#panel.grid.minor = element_blank(),
#panel.grid.major = element_blank(),
#plot.title = element_text(size = 100, color = "#2171b5", hjust = 0.5, vjust = -22),
#plot.subtitle = element_text(size = 14, color = "#ac63a0", hjust = 0.5, vjust = 0),
#plot.caption = element_text(size = 40, color = "grey60", hjust = 0.5, vjust = 120),
#axis.title.x = element_text(size = 10, color = "grey20", hjust = 0.5, vjust = -6),
legend.text = element_text(size = 9, color = "grey20"),
legend.title = element_text(size = 10, color = "grey20"),
strip.text = element_text(size = 12),
#plot.margin = unit(c(t = -2.5, r = -10, b = -10, l = -10), "lines"),
axis.title.y = element_blank(),
axis.ticks = element_blank(),
#axis.text.x = element_blank(),
#axis.text.y = element_blank()
)