dist_wlatlng_cpp: dist_wlatlng_cpp

Description

calculate distance between coordinate1 and coordinate2

Usage

dist_wlatlng_mi_cpp(lat1, lng1, lat2, lng2)
dist_wlatlng_km_cpp(lat1, lng1, lat2, lng2)
distSgl_wlatlng_cpp(lat1, lng1, lat2, lng2, measure = "mi")
distRpl_wlatlng_cpp(lat1, lng1, lat2, lng2, measure = "mi", distRpl_GS = 100L)

Arguments

lat1

latitude of coordinate1

lng1

longitude of coordinate1

lat2

latitude of coordinate2

lng2

longitude of coordinate2

measure

"mi" (mile) or "km" (kilometer)

distRpl_GS

The grain size of a parallel algorithm sets a minimum chunk size for parallelization. In other words, at what point to stop processing input on separate threads (as sometimes creating more threads can degrade the performance of an algorithm by introducing excessive synchronization overhead). Default is 100.

Details

calculate the great circle distance between 2 points with Haversine formula, which deliberately ignores elevation differences.

Haversine formula (from R.W. Sinnott, "Virtues of the Haversine", Sky and Telescope, vol. 68, no. 2, 1984, p. 159):

dlon = lon2 - lon1

dlat = lat2 - lat1

a = sin^2(dlat/2) + cos(lat1) * cos(lat2) * sin^2(dlon/2)

c = 2 * arcsin(min(1,sqrt(a)))

d = R * c

dist_wlatlng_mi_cpp:

calculate distance between coordinate1 and coordinate2 in mile

dist_wlatlng_km_cpp:

calculate distance between coordinate1 and coordinate2 in kilometer

distSgl_wlatlng_cpp:

calculate distance between coordinate1 and coordinate2 in mile (measure = "mi") or kilometer (measure = "km"), default is mile.

implement as serial computing over vector of lat1, lng1, lat2, lng2

distRpl_wlatlng_cpp:

calculate distance between coordinate1 and coordinate2 in mile (measure = "mi") or kilometer (measure = "km"), default is mile.

implement as parallel computing over vector of lat1, lng1, lat2, lng2 via RcppParallel