Colour Scales
We can also create a scale which will automatically generate a colour based on our data value.
The colour scales are:
- category10
- category20
- category20b
- category20c
category 10 contains 10 colours, the rest contain 20 colours. These colours have been specially designed to be harmonious and attractive.
Generating a colour scale
We can make a colour scale by calling one of the category functions:
let colour = d3.scale.category20();
We can now make a colour simply by calling the colour function:
let bars = d3.selectAll("rect");
bars.attr("color", function (d, i) {
return colour(i);
});
Exercise - assign colours to your chart
Use the colours function to automatically assign colours to one of your charts.