R/table_getNearestDistance.R
table_getNearestDistance.Rd
Returns distances from known locations in locationTbl
,
one for each incoming location. If no known location is found within
distanceThreshold
meters for a particular
incoming location, that distance in the vector will be NA
.
table_getNearestDistance( locationTbl = NULL, longitude = NULL, latitude = NULL, distanceThreshold = NULL, measure = "geodesic" )
locationTbl | Tibble of known locations. |
---|---|
longitude | Vector of longitudes in decimal degrees E. |
latitude | Vector of latitudes in decimal degrees N. |
distanceThreshold | Distance in meters. |
measure | One of "haversine" "vincenty", "geodesic", or "cheap"
specifying desired method of geodesic distance calculation. See |
Vector of distances from known locations.
The measure "cheap"
may be used to speed things up depending on
the spatial scale being considered. Distances calculated with
measure = "cheap"
will vary by a few meters compared with those
calculated using measure = "geodesic"
.
library(MazamaLocationUtils) locationTbl <- get(data("wa_monitors_500")) # Wenatchee lon <- -120.325278 lat <- 47.423333 # Too small a distanceThreshold will not find a match table_getNearestDistance(locationTbl, lon, lat, distanceThreshold = 50)#> [1] NA# Expanding the distanceThreshold will find one table_getNearestDistance(locationTbl, lon, lat, distanceThreshold = 5000)#> [1] 1495.593