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Lines on Maps in R

How to draw lines, great circles, and contours on maps in R. Lines on maps can show distance between geographic points or be contour lines (isolines, isopleths, or isarithms).


New to Plotly?

Plotly is a free and open-source graphing library for R. We recommend you read our Getting Started guide for the latest installation or upgrade instructions, then move on to our Plotly Fundamentals tutorials or dive straight in to some Basic Charts tutorials.

Flight Paths Map

library(plotly)
library(dplyr)
# airport locations
air <- read.csv('https://raw.githubusercontent.com/plotly/datasets/master/2011_february_us_airport_traffic.csv')
# flights between airports
flights <- read.csv('https://raw.githubusercontent.com/plotly/datasets/master/2011_february_aa_flight_paths.csv')
flights$id <- seq_len(nrow(flights))

# map projection
geo <- list(
  scope = 'north america',
  projection = list(type = 'azimuthal equal area'),
  showland = TRUE,
  landcolor = toRGB("gray95"),
  countrycolor = toRGB("gray80")
)

fig <- plot_geo(locationmode = 'USA-states', color = I("red"))
fig <- fig %>% add_markers(
  data = air, x = ~long, y = ~lat, text = ~airport,
  size = ~cnt, hoverinfo = "text", alpha = 0.5
)
fig <- fig %>% add_segments(
    data = group_by(flights, id),
    x = ~start_lon, xend = ~end_lon,
    y = ~start_lat, yend = ~end_lat,
    alpha = 0.3, size = I(1), hoverinfo = "none"
  )
fig <- fig %>% layout(
    title = 'Feb. 2011 American Airline flight paths<br>(Hover for airport names)',
    geo = geo, showlegend = FALSE, height=800
  )

fig

London to NYC Great Circle

library(plotly)

fig <- plot_geo(lat = c(40.7127, 51.5072), lon = c(-74.0059, 0.1275))
fig <- fig %>% add_lines(color = I("blue"), size = I(2))
fig <- fig %>% layout(
    title = 'London to NYC Great Circle',
    showlegend = FALSE,
    geo = list(
      resolution = 50,
      showland = TRUE,
      showlakes = TRUE,
      landcolor = toRGB("grey80"),
      countrycolor = toRGB("grey80"),
      lakecolor = toRGB("white"),
      projection = list(type = "equirectangular"),
      coastlinewidth = 2,
      lataxis = list(
        range = c(20, 60),
        showgrid = TRUE,
        tickmode = "linear",
        dtick = 10
      ),
      lonaxis = list(
        range = c(-100, 20),
        showgrid = TRUE,
        tickmode = "linear",
        dtick = 20
      )
    )
  )

fig

Contour lines on globe

df <- read.csv('https://raw.githubusercontent.com/plotly/datasets/master/globe_contours.csv')
df$id <- seq_len(nrow(df))

library(tidyr)
d <- df %>%
  gather(key, value, -id) %>%
  separate(key, c("l", "line"), "\\.") %>%
  spread(l, value)

geo <- list(
  showland = TRUE,
  showlakes = TRUE,
  showcountries = TRUE,
  showocean = TRUE,
  countrywidth = 0.5,
  landcolor = toRGB("grey90"),
  lakecolor = toRGB("white"),
  oceancolor = toRGB("white"),
  projection = list(
    type = 'orthographic',
    rotation = list(
      lon = -100,
      lat = 40,
      roll = 0
    )
  ),
  lonaxis = list(
    showgrid = TRUE,
    gridcolor = toRGB("gray40"),
    gridwidth = 0.5
  ),
  lataxis = list(
    showgrid = TRUE,
    gridcolor = toRGB("gray40"),
    gridwidth = 0.5
  )
)

fig <- plot_geo(d)
fig <- fig %>% group_by(line)
fig <- fig %>% add_lines(x = ~lon, y = ~lat)
fig <- fig %>% layout(
    showlegend = FALSE, geo = geo,
    title = 'Contour lines over globe<br>(Click and drag to rotate)'
  )

fig

What About Dash?

Dash for R is an open-source framework for building analytical applications, with no Javascript required, and it is tightly integrated with the Plotly graphing library.

Learn about how to install Dash for R at https://dashr.plot.ly/installation.

Everywhere in this page that you see fig, you can display the same figure in a Dash for R application by passing it to the figure argument of the Graph component from the built-in dashCoreComponents package like this:

library(plotly)

fig <- plot_ly() 
# fig <- fig %>% add_trace( ... )
# fig <- fig %>% layout( ... ) 

library(dash)
library(dashCoreComponents)
library(dashHtmlComponents)

app <- Dash$new()
app$layout(
    htmlDiv(
        list(
            dccGraph(figure=fig) 
        )
     )
)

app$run_server(debug=TRUE, dev_tools_hot_reload=FALSE)