VillageName1, VillageName2
Village1, Village2
Village1, Village3
Village1, Village4
...
Village2379, Village2378

sea <- readOGR('World_EEZ_v8_2014.shp')
ocean_indo_shapefile <- sea[sea$Country == "Indonesia", ]

#this function creates the points from Village1 to Village2 in 100m intevals, output is a dataframe
points <- create_coordinates(village1_lat, village1_long, village2_lat, village2_long, 0.1)

coordinates(points) <- ~ Longitude + Latitude
proj4string(points) <- proj4string(ocean_indo_shapefile)
#the calculation below is slow
water_in_meter <- length(points[ocean_indo_shapefile,])