View source: R/table_getNearestDistance.R
table_getNearestDistance | R Documentation |
Returns distances between known locations in locationTbl
,
and a vector of target locations specified by longitude
and latitude
.
Only a single distance to the closest known location is returned for each
incoming target 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 = c("geodesic", "haversine", "vincenty", "cheap") )
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) # Expanding the distanceThreshold will find one table_getNearestDistance(locationTbl, lon, lat, distanceThreshold = 5000)
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