make_bbox: Compute a bounding box
In KimByoungmo/modefiedggmap: Spatial Visualization with ggplot2

Compute a bounding box for a given longitude / latitude collection.

1	make_bbox(lon, lat, data, f = 0.05)

`lon`	longitude
`lat`	latitude
`data`	(optional) a data frame containing lon and lat as variables
`f`	number specifying the fraction by which the range should be extended

make_bbox(lon, lat, data = crime)

(lon <- sample(crime$lon, 10))
(lat <- sample(crime$lat, 10))
make_bbox(lon, lat)
make_bbox(lon, lat, f = .10) # bigger box