Flow map(Travel Path) Using Lat and Long in R

Question

I am trying to plot flow map (for singapore) . I have Entry(Lat,Long) and Exit (Lat,long). I am trying to map the flow from entry to exit in singapore map.

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Answer 1

Alternative answer using leaflet and geosphere

#get Packages
require(leaflet)
require(geosphere)

#format data
a$Entry_Station_Long = as.numeric(as.character(a$Entry_Station_Long))
a$Entry_Station_Lat = as.numeric(as.character(a$Entry_Station_Lat))
a$Exit_Station_Long = as.numeric(as.character(a$Exit_Station_Long))
a$Exit_Station_Lat = as.numeric(as.character(a$Exit_Station_Lat))
a$id = as.factor(as.numeric(as.factor(a$token_id)))

#create some colors
factpal <- colorFactor(heat.colors(30), pathList$id)

#create a list of interpolated paths
pathList = NULL
for(i in 1:nrow(a))
{
tmp = gcIntermediate(c(a$Entry_Station_Long[i],
                 a$Entry_Station_Lat[i]),
               c(a$Exit_Station_Long[i],
                 a$Exit_Station_Lat[i]),n = 25,
               addStartEnd=TRUE)
tmp = data.frame(tmp)
tmp$id = a[i,]$id
tmp$color = factpal(a[i,]$id)
pathList = c(pathList,list(tmp))
}

#create empty base leaflet object
leaflet() %>% addTiles() -> lf

#add each entry of pathlist to the leaflet object
for (path in pathList)
{
  lf %>% addPolylines(data = path,
                      lng = ~lon, 
                      lat = ~lat,
                      color = ~color) -> lf

}
#show output
lf

Note that as I mentioned before there is no way of geosphering the paths in such a small locality - the great circles are effectively straight lines. If you want the rounded edges for sake of aesthetics you may have to use the geom_curve way described in my other answer.