R/table_findAdjacentLocations.R
table_findAdjacentLocations.Rd
Calculates distances between all locations within a known
locations table and returns a tibble with the row indices and separation
distances of those records separated by less than distanceThreshold
meters.
It is useful when working with new metadata tables to identify ajacent
locations early on so that decisions can be made about the appropriateness
of the specified distanceThreshold
.
table_findAdjacentLocations( locationTbl = NULL, distanceThreshold = NULL, measure = "geodesic" )
locationTbl | Tibble of known locations. |
---|---|
distanceThreshold | Distance in meters. |
measure | One of "haversine" "vincenty", "geodesic", or "cheap"
specifying desired method of geodesic distance calculation. See |
Tibble of known locations separated by less than
distanceThreshold
meters.
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) meta <- wa_airfire_meta # Any locations closer than 2 km? meta %>% table_findAdjacentLocations(distanceThreshold = 2000) %>% dplyr::select(monitorID, siteName, timezone)#> monitorID siteName #> lon_.122.671_lat_47.029_usfs.1078 lon_.122.671_lat_47.029_usfs.1078 #> lon_.122.677_lat_47.028_usfs.1078 lon_.122.677_lat_47.028_usfs.1078 #> timezone #> lon_.122.671_lat_47.029_usfs.1078 America/Los_Angeles #> lon_.122.677_lat_47.028_usfs.1078 America/Los_Angeles# How about 4 km? meta %>% table_findAdjacentLocations(distanceThreshold = 4000) %>% dplyr::select(monitorID, siteName, timezone)#> monitorID #> lon_.122.671_lat_47.029_usfs.1078 lon_.122.671_lat_47.029_usfs.1078 #> 530330057_01 530330057_01 #> 530330080_01 530330080_01 #> 530330057_01.1 530330057_01 #> lon_.122.677_lat_47.028_usfs.1078 lon_.122.677_lat_47.028_usfs.1078 #> 530330080_01.1 530330080_01 #> 530330030_01 530330030_01 #> 530331011_01 530331011_01 #> siteName timezone #> lon_.122.671_lat_47.029_usfs.1078 America/Los_Angeles #> 530330057_01 Seattle-Duwamish America/Los_Angeles #> 530330080_01 Seattle-Beacon Hill America/Los_Angeles #> 530330057_01.1 Seattle-Duwamish America/Los_Angeles #> lon_.122.677_lat_47.028_usfs.1078 America/Los_Angeles #> 530330080_01.1 Seattle-Beacon Hill America/Los_Angeles #> 530330030_01 Seattle-10th & Weller America/Los_Angeles #> 530331011_01 Seattle-South Park America/Los_Angeles