R/haversine.R

In RandallShanePhD/geoPlot: Geocodes street or ip addresses and plots them on a map.

haversine <-
function(xLat,xLon,yLat,yLon){
    earthR <- 6371 #using mean radius
    mLat <- as.double(xLat)
    bLat <- as.double(yLat)
    mLong <- as.double(xLon)
    bLong <- as.double(yLon)
    changeLat <- degrees2radians(mLat - bLat)
    changeLong <- degrees2radians(mLong - bLong)  
    a <- sin(changeLat/2) * sin(changeLat/2) + cos(degrees2radians(mLat)) * 
      cos(degrees2radians(bLat)) * sin(changeLong/2) * sin(changeLong/2)
    c <- 2 * atan2(sqrt(a), sqrt(1-a))
    distKm <- earthR * c
    distMi <- as.double(distKm * 0.621371192)
    output <- c(xLat,xLon,yLat,yLon,distKm,distMi)
    return(output)}