Generates a base OSM plot ready for polygon, line, and point objects to be
overlain with add_osm_objects.
Usage
osm_basemap(bbox, structures, bg = "gray20")
Arguments
bbox
bounding box (Latitude-longitude range) to be plotted. A 2-by-2
matrix of 4 elements with columns of min and max values, and rows of x and y
values. Can also be an object of class sf, for example as returned
from extract_osm_objects or the osmdata package, in which case
the bounding box will be extracted from the object coordinates.
structures
Data frame returned by osm_structures used
here to specify background colour of plot; if missing, the colour is
specified by bg.
bg
Background colour of map (default = gray20) only if
structs not given).