Given a latitude or longitude coordinate, return that coordinate jittered
plus or minus a certain maximum amount. This function assumes a spherical
earth when calculating the maximum amount to jitter.
     
    
    Usage
    jitter_latlong(coord, type = c("lat", "long"), latitude, km = 1)
 
    
    Arguments
- coord
- The coordinate in degrees 
- type
- Whether the coordinate is latitude or longitude 
- latitude
- If the coordinate is longitude, then the latitude to use for
calculating the maximum amount to jitter. 
- km
- The maximum number of kilometers to jitter a point plus or minus. 
 
    
    Value
    The jittered coordinate in degrees.
     
    
    
    Examples
    jitter_latlong(-73, type = "long", lat = 43, km = 1)
#> [1] -73.01152
jitter_latlong(42, type = "lat", km = 1)
#> [1] 41.99675