Plotting thematic maps
Now we have everything to create our first thematic map. Let's pass the val
vector to the previously used map
function (or plot
it using the us
object), specify a plot title, add a blue point for Houston, and then create a legend, which shows the quantiles of the overall number of cancelled flights as a reference:
> map("state", col = rgb(1, 0, 0, sqrt(val/max(val))), fill = TRUE) > title('Number of cancelled flights from Houston to US states') > points(h$lon, h$lat, col = 'blue', pch = 13) > legend('bottomright', legend = round(quantile(val)), + fill = rgb(1, 0, 0, sqrt(quantile(val)/max(val))), box.col = NA)
Please note ...
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