riverplot (version 0.10)

minard: Minard Napoleon Russian campaign data

Description

The data set used by Charles Joseph Minard to generate the famous graph. The example below shows how to recreate the main panel of the graph using riverplot from the provided data.

Usage

minard

Format

Named list with two data frames:

nodes

data frame with geographic locations of the Napoleon army (longitude and latitude) and the direction of the march

edges

connections between positions

Details

First, node and edge data frames must get new column names (see makeRiver function for details). Then, based on the direction of the Napoleon army, style information (right and left edge color style for each node) is entered in the nodes variable. Then, a riverplot object is generated from the nodes and edges data frames.

To use the same color coding as Minard, the direction variable is converted to color codes in the col column of the edges object.

Finally, a plot is created using lty=1 and a style in which nodes are not shown, and the edges are straight (like in the original Minard plot) rather than curved.

Examples

# NOT RUN {
# example how to convert data into a riverplot object
data(minard)
nodes <- minard$nodes
edges <- minard$edges
colnames(nodes) <- c("ID", "x", "y")
colnames(edges) <- c("N1", "N2", "Value", "direction")

# color the edges by troop movement direction
edges$col <- c("#e5cbaa", "black")[factor(edges$direction)]

# color edges by their color rather than by gradient between the nodes
# The "edgecol" column is interpreted as a style keyword with value "col"
edges$edgecol <- "col"

# generate the riverplot object and a style
river <- makeRiver(nodes, edges)
style <- list(edgestyle= "straight", nodestyle= "invisible")

# plot the generated object. Given that we want to plot the cities as well
# (external data), the user coordinates for the plot and for the external
# data should be the same. This is achieved by the adjust.usr option.
# Alternatively, one can call plot.new, set usr manually and call riverplot
# with the options rescale=FALSE and add=TRUE.
# plot_area parameter is for creating suitable margins within the plot area
par(bg="grey98", mar=rep(3,4))
plot(river, lty=1, default_style=style, plot_area=c(0.9, 0.7), adjust.usr=TRUE)
u <- par("usr")
rect(u[1], u[3], u[2], u[4])

# add latitude and longitude
abline(h=54:56, col="grey")
bglabel(u[1], 54:56, sprintf("%d<U+00B0>N", 54:56), pos="topright", bg=NA, col="grey", font=3)
lbl <- seq(20, 40, by=5)
abline(v=lbl, col="grey")
bglabel(lbl, u[3], sprintf("%d<U+00B0>E", lbl), pos="topright", bg=NA, col="grey", font=3)

# Add cities. Use "bglabel()" to have a background frame and better
# positioning.
with(minard$cities, points(Longitude, Latitude, pch=19))
with(minard$cities, bglabel(Longitude, Latitude, Name, pos="topright"))
# }