Calculate a zoom given a bounding box

calc_zoom can calculate a zoom based on either (1) a data frame with longitude and latitude variables, (2) a longitude range and latitude range, or (3) a bounding box (bbox specification). The specification for (1) is identical to that of most R functions, for (2) simply put in a longitude range into lon and a latitude range into lat, and for (3) put the bounding box in for the lon argument.

Usage

calc_zoom(lon, lat, data, adjust = 0, f = 0.05)

Arguments

lon

longitude, see details

lat

latitude, see details

data

(optional) a data frame containing lon and lat as variables

adjust

number to add to the calculated zoom

f

argument to pass to make_bbox

See also

make_bbox(), bb2bbox()

Examples

# From data
calc_zoom(lon, lat, wind)
#> Error in eval(expr, envir, enclos): object 'wind' not found

# From range
lon_range <- extendrange( wind$lon )
#> Error in eval(expr, envir, enclos): object 'wind' not found
lat_range <- extendrange( wind$lat )
#> Error in eval(expr, envir, enclos): object 'wind' not found
calc_zoom(lon_range, lat_range)
#> Error in eval(expr, envir, enclos): object 'lon_range' not found

# From bounding box
box <- make_bbox(lon, lat, data = crime)
#> Error in eval(expr, envir, enclos): object 'crime' not found
calc_zoom(box)
#> Error in calc_zoom(box): if specifying a bounding box, the format should match that of make_bbox.