[R] Plotting shipment routs on a world map

[Bernard McGarvey]

I have used the ggplot2 package to create a world map, the png file of the output is attached. The code I use is below:

library(ggplot2)
library(mapproj)
long_Min <- -180.0
long_Max <- 180.0
lat_Min <- -50.0
lat_Max <- 80.0
Width <- 12.0
Height <- 2.0*Width*(lat_Max-lat_Min)/(long_Max-long_Min)
windows(width = Width, height = Height,record = TRUE)
World_map_data <- map_data("world")
World_map_dataS <- subset(World_map_data, (long >= long_Min & long <= long_Max) & (lat >= lat_Min & lat <= lat_Max))
#Europe_data <- map_data("europe")
O_lat <- runif(10, min=lat_Min, max=lat_Max)
O_long <- runif(10, min=long_Min, max=long_Max)
D_lat <- runif(10, min=lat_Min, max=lat_Max)
D_long <- runif(10, min=long_Min, max=long_Max)
Routes = data.frame(O_lat,O_long, D_lat,D_long)
g1 <- ggplot(World_map_dataS, aes(x=long, y=lat, group=group, fill=region)) +
  geom_polygon(fill="white", colour="blue") +
  coord_map("mercator")
g1


I have a list of shipments with the lat/long of the Origin cities and destination cities in a dataframe Routes. A test example is shown below:

structure(list(O_lat = c(57.8440704662353, 43.4692783257924, 
34.197948181536, -13.9658199064434, 28.1358464458026, 54.8644948145375, 
54.7105941944756, 0.960986674763262, -9.04949014307931, 67.3708150233142
), O_long = c(-135.800734693184, -139.97953729704, 130.949327526614, 
120.016278969124, -81.3588178250939, 107.188451411203, -166.396527299657, 
6.01017326116562, 119.992827912793, 68.8450227119029), D_lat = c(13.1392757641152, 
-48.4003935428336, -18.0977397086099, 7.47306475648656, 38.8207479682751, 
-6.95962310535833, 21.4299688511528, 77.7941568545066, -39.2934810533188, 
-5.45942842029035), D_long = c(-161.594757176936, -8.55208304710686, 
59.6322040446103, 16.3289373647422, -82.6615255884826, -150.326664168388, 
-86.496180742979, -162.877350552008, -119.206758281216, -110.952316028997
)), class = "data.frame", row.names = c(NA, -10L))


this dataframe consists of 10 shipments. How do I add these shipments as individual lines onto the world map. If I need to I can convert from lat & long to map coordinates using the mercator projection equations. My issue is what ggplot commands to use.

Thanks

Bernard McGarvey


Director, Fort Myers Beach Lions Foundation, Inc.


Retired (Lilly Engineering Fellow).
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