Plotting Airbnb data over NASA's "black marble" geotiff - r

Question

I am trying to create an image similar to that presented by Ricardo Bion of Airbnb but I would like to plot the visualization over the NASA "black marble" image to give more context as I don't have nearly the data density of the Airbnb dataset.
I downloaded the Nasa black marble image here using the global map 13500x6750 (3km) GeoTIFF 39 MB option.
This issue I keep running into is most of the options and explanations available online have been depreciated in the past few years. I tried using EBImage as shown here but ebimageGrob has been removed from gridExtra. I also tried to use the rasterVis package as shown here but the code breaks at the colorable step.
Here is as far as I have made it trying to layer the tiff behind the plot using the ggplot2 annotation_raster option (this gives the lines between the destinations but only a white background):
library(ggplot2)
library(ggmap)
library(sp)
library(grid)
library(geosphere)
library(plyr)
library(tiff)
# source the theme_map for ggplot2
# source("https://dl.dropboxusercontent.com/u/2364714/theme_map.R")
# in the original post I had a data.frame with 500k rows of top origin destination pairs
trips <- data.frame(origin = c("San Francisco", "Sydney", "Chicago"),
destination = c("Paris", "Tokyo", "Boston"),
stringsAsFactors = FALSE)
# get lat and lon of cities
trips$geocode_origin <- suppressMessages(geocode(trips$origin))
trips$geocode_destination <- suppressMessages(geocode(trips$destination))
# get intermediate points between the two locations
arch <- gcIntermediate(trips$geocode_origin,
trips$geocode_destination,
n=100,
breakAtDateLine=FALSE,
addStartEnd=TRUE, sp=TRUE)
# http://docs.ggplot2.org/0.9.3.1/fortify.map.html
arch_fortified <- ldply(arch#lines, fortify)
earth <- readTIFF("~/Downloads/dnb_land_ocean_ice.2012.13500x6750_geo.tif")
theme_map <- function(base_size = 12) {
require(grid)
theme_grey(base_size) %+replace%
theme(
axis.title = element_blank(),
axis.text = element_blank(),
panel.grid = element_blank(),
axis.ticks.length = unit(0,"cm"),
panel.margin = unit(0,"lines"),
plot.margin = unit(c(0,0,0,0),"lines"),
complete = TRUE,
panel.background = element_rect(fill = NA, colour=NA)
)
}
# a few lines of ggplot2 code
ggplot() +
geom_line(aes(long,lat,group=group), data=arch_fortified, alpha=0.1,size=1, colour="skyblue1") +
coord_cartesian(ylim =c(-45, 70), xlim=c(-165, 165)) +
theme_map() +
geom_point(aes(lon, lat),data=trips$geocode_origin, alpha = 0.8, size = 1, colour = "white") +
geom_point(aes(lon, lat),data=trips$geocode_destination, alpha = 0.8, size = 1, colour = "white") +
annotation_raster(earth, -180, 180, -90, 90)
Thanks!

Answer 1

I just had to slightly modify your plotting code to get it work:
ggplot(arch_fortified) +
coord_cartesian(ylim =c(-45, 70), xlim=c(-165, 165)) +
theme_map() +
annotation_raster(earth, -180, 180, -90, 90) +
geom_line(aes(long,lat,group=group), alpha=0.1,size=1, colour="skyblue1") +
geom_point(aes(lon, lat),data=trips$geocode_origin, alpha = 0.8, size = 1, colour = "white") +
geom_point(aes(lon, lat),data=trips$geocode_destination, alpha = 0.8, size = 1, colour = "white")
Note that you should first draw the background and only then the lines and points, otherwise the image will cover other plot elements.