In Clement-Viguier/ggriverlab: Introduce river labels in the ggplot2 framework

Labels for rivers in the ggplot2 framework

ggriverlab aims to introduce labels that follow lines to creat nice maps with ggplot2. While this function is common in GIS software, I could not find satisfying solutions for R plotting, so here is my take on it.

Installation

The package can be installed from github with the help of the devtool package.

# install.packages("devtools")
devtools::install_github("Clement-Viguier/ggriverlab")

Demo

library(ggriverlab)
library(riverdist)
library(ggplot2)
library(dplyr)


river <- as.data.frame(Gulk$lines[4])
colnames(river) <- c("x", "y")

ggplot(river, aes(x,y)) + geom_path() + coord_fixed()
ggplot(river, aes(x,y)) + geom_path() + coord_fixed() + geom_river_label(aes(label = "Gulk", offset = 0.24), reverse = F)

?geom_river_label

# Plotting the full river

branches <- 1:14
branch_list <- lapply(branches, function(b, Gulk){
  river <- as.data.frame(Gulk$lines[b])
  colnames(river) <- c("x", "y")
  river$branch <- b
  return(river)
}, Gulk)
full_river<- do.call(rbind, branch_list)

ggplot(full_river, aes(x,y, group = branch, colour = as.factor(branch))) + geom_path() + coord_fixed() + geom_river_label(aes(label = "Gulk"), check_length = F) +
 theme_minimal() + theme(legend.position = "none")

# Check_length avoids to print labels that cannot fit the river portion.
ggplot(full_river, aes(x,y, group = branch, colour = as.factor(branch))) + geom_path() + coord_fixed() + geom_river_label(aes(label = "Gulk"), check_length = T) +
  theme_minimal() +theme(legend.position = "none")

ggplot(full_river, aes(x,y, group = branch, colour = as.factor(branch))) + geom_path() + coord_fixed() + geom_river_label(aes(label = "Gulk"), offset = 0.15, dist = 0.01, check_length = T) +
  theme_minimal() +theme(legend.position = "none")

The geom_river_label function can be used to plot multiple river, or branches at once. If they are too short, the label can be exclude thanks to the option check_length = T. The above code produce the following map of the river:

# install.packages('devtools')
# devtools::install_github('thomasp85/gganimate')
library(gganimate)

# generate data for the animation
offsets <- seq(0.05, 0.9, length.out = 20)
list_data <- lapply(offsets, function(os, river){
  river$off <- os
  return(river)
}, river)
data_offset <- do.call(rbind, list_data)

anim <- ggplot(data_offset, aes(x,y)) + geom_path() + coord_fixed() + geom_river_label(aes(label = "Gulk", offset = off), relative = T, check_length = F, reverse = F, repeated = F)+
  transition_states(off, 1, 3)
anim
anim_save("Images/moving_label_smooth.gif", last_animation())

The effect of the different parameters on the label position and shape can be seen here:

Larger scale data

Oceans and rivers

library(raster)
library(tidyr)

ne_rivers <- shapefile("./data/ne_50m_rivers_lake_centerlines.shp")
ne_lands  <- shapefile("./data/ne_50m_land.shp")
ne_lakes  <- shapefile("./data/ne_50m_lakes.shp")

data <- ne_rivers@data
data$id <- rownames(data)
rivers_df <- fortify(ne_rivers) %>% left_join(data, by = "id")

lands <- fortify(ne_lands)


ggplot(rivers_df, aes(long, lat, group = group)) +
   geom_path(aes(), colour = "steelblue") + geom_river_label(aes(label = label), colour = "steelblue") +
  coord_fixed() + 
  facet_wrap(~id, scales = "free")+
  theme_linedraw()+
  theme_classic() + theme(panel.background = element_rect(fill = "steelblue"))

TO DO LIST

• $\checkmark$ make it work with point: place points along the path in place of letters;
• $\checkmark$ include in geom;
• $\Box$ make it work with entire labels as an option;
• $\checkmark$ make it work with letters;

TO DO if the rest is done and clean

• $\Box$ make river specific geom (size~order);
• $\Box$ make interactive tool to test the parameters;
• $\checkmark$ find good default parameters;
• $\Box$ scale against text size or plot size ?;

Clement-Viguier/ggriverlab documentation built on Nov. 8, 2019, 10:02 p.m.