问题
I am creating a map of Brazil with its state boundaries, which is straight forward to achieve using ggplot2 and geom_sf.
However, this time around, instead of color filling each state with data, I want to fill each state's boundaries with an external image (png), similar to this example of the largest employer in each state.
I have tried a few settings of geom_image and even geom_flag to no avail (hence why I am not posting any code here).
Are there any suggestions on how to approach this problem?
回答1:
You can try cartography::getPngLayer/pngLayer. These two functions takes a png as input, geotag and crop it to the shape of a given polygon and creates a rasterbrick object (as a tile) that you can manipulate and plot:
https://dieghernan.github.io/cartographyvignette#png-layer
来源：https://stackoverflow.com/questions/64318505/how-to-fill-map-boundaries-with-external-images