Convert a bb specification to a bbox specification
In ggmap, all maps (class ggmap) have the bb attribute, a data frame bounding box specification in terms of the bottom left and top right points of the spatial extent. This function converts this specification to a named double vector (with names left, bottom, right, top) specification that is used in some querying functions (e.g. get_stamenmap).
bb2bbox(bb)
bb |
a bounding box in bb format (see examples) |
a bounding box in bbox format (see examples)
David Kahle david.kahle@gmail.com
## Not run: # cut down on R CMD check time
# grab a center/zoom map and compute its bounding box
gc <- geocode("white house, washington dc")
map <- get_map(gc)
(bb <- attr(map, "bb"))
(bbox <- bb2bbox(bb))
# use the bounding box to get a stamen map
stamMap <- get_stamenmap(bbox)
ggmap(map) +
geom_point(
aes(x = lon, y = lat),
data = gc, colour = "red", size = 3
)
ggmap(stamMap) +
geom_point(
aes(x = lon, y = lat),
data = gc, colour = "red", size = 3
)
## End(Not run)Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.