Acknowledgements
This time it was Ehsan that found the bug in the script.
Navigator
Task 1
library(data.table)
runoff_stations <- fread('./data/raw/runoff_stations.csv')
runoff_stations[, sname := factor(abbreviate(station))]
runoff_stations[, id := factor(id)]
runoff_stations[, altitude := round(altitude, 0)]
runoff_area_alt <- runoff_stations[, .(sname, area, altitude)]
Task 2
ggplot(data = runoff_stations) +
geom_point(aes(x = area, y = altitude))
Task 3
ggplot(data = runoff_stations, aes(x = area, y = altitude, col = size)) +
geom_point() +
geom_text(label = runoff_stations$sname,
position = position_jitter(width = 50, height = 50)) +
theme_minimal()
ggplot(data = runoff_stations, aes(x = lon, y = lat, col = altitude)) +
geom_point() +
geom_text(label = runoff_stations$sname,
position = position_jitter(width = 0.2, height = 0.2)) +
scale_color_gradient(low = 'dark green', high = 'brown') +
theme_bw()
Task 4
to_plot <- runoff_stations[, .(sname, start, end)]
to_plot <- melt(to_plot, id.vars = 'sname')
ggplot(data = to_plot, aes(x = value, y = sname)) +
geom_line(lwd = 2, col = 'dark red') +
theme_bw()
Explorer
Question 1
Catchment area units are km^2 River runoff units are m^3/s
Question 2
runoff_stations[, mean(area)] #data.table way (faster)
mean(runoff_stations$area) #data.frame way
runoff_day[, mean(value)]
Question 4
Altitude refers to the altitude (or elevation) of the station that we measure the river runoff. High altitude means that the station is on the hills. Area corresponds to the total catchment area (in sq. kilometers) at this location.
Imagine you are standing at Alpes near the beginning of the river (upstream). The length of the river up to this point is still short, therefore the catchment (the area from where rainfall water reaches the river) is also small.
Now imagine that you stand to the river mouth at the sea (downstream). Now the river behind you is at full length. Thus the total catchment area is much bigger.