allCharts = {
const svg = d3.create("svg")
.attr("width", width)
.attr("height", height);
svg.append("g")
.attr("class", "scatterplot");
svg.append("g")
.attr("transform", `translate(${chartWidth}, 0)`)
.attr("class", "linechart");
return svg.node();
}
// this block is updated whenever something changes
// eg. the selected year, the selectedCountry, or the brushedCountries
// first the changes will trigger an update in the makeScatterPlot and makeLineChart cells
// this will then trigger an update of this cell as it uses the results of those cells
// now we just need to make sure that things are *updated* instead of being appended over and over again
{
const chartsContainer = d3.select(allCharts);
chartsContainer.select("g.scatterplot")
.call(makeScatterPlot);
chartsContainer.select("g.linechart")
.call(makeLineChart);
}
radiusScale = d3.scaleSqrt() // <-- use square root scale instead of linear scale for circle area
.domain([0, d3.max(gapminderData, d => d.pop)])
.range([0, 25])
brush = d3.brush()
.extent([
[d3.min(xScaleScatter.range()), d3.min(yScaleScatter.range())],
[d3.max(xScaleScatter.range()), d3.max(yScaleScatter.range())]
])
.on("brush end", (event) => {
if (event.selection === null) {
mutable brushedCountries = [];
} else {
const [[x0, y0], [x1, y1]] = event.selection;
mutable brushedCountries = gapminderData.filter(d => d.year === year)
.filter(d => {
return x0 <= xScaleScatter(d.fertility) &&
x1 >= xScaleScatter(d.fertility) &&
y0 <= yScaleScatter(d.life_expect) &&
y1 >= yScaleScatter(d.life_expect);
}).map(d => d.country);
}
})
makeScatterPlot = circlesContainer => {
const scatterData = gapminderData.filter(d => d.year === year);
circlesContainer.selectAll(".brushContainer")
.data([1])
.join("g")
.attr("class", "brushContainer")
.call(brush);
circlesContainer.selectAll("circle.dot")
.data(scatterData, d => d.country) // <-- provide a 🔑 key function for joining data to SVG elements
// this key function is needed for proper animation, see https://observablehq.com/@philippkoytek/d3-part-3-selection-join-explained
.join("circle")
.sort((a, b) => b.pop - a.pop) // sort the data so that big bubbles are in the background
.attr("class", "dot")
.on("click", (event, d) => {
if (d.country === selectedCountry) {
mutable selectedCountry = null;
}
else mutable selectedCountry = d.country;
})
.attr("opacity", 0.8) // make bubbles a bit transparent
.attr("fill", d => {
if(d.country === selectedCountry) {
return "#3484c7";
} else if (brushedCountries.includes(d.country)) {
return "#573B9F";
} else {
return "lightgrey";
}
})
.transition().duration(1000) // <-- animate the update of the following attributes (cx, cy, r, fill)
.attr("cx", d => xScaleScatter(d.fertility))
.attr("cy", d => yScaleScatter(d.life_expect))
.attr("r", d => radiusScale(d.pop));
circlesContainer.selectAll("g.yAxis")
.data([1])
.join("g")
.attr("class", "yAxis")
.call(yAxisScatter);
circlesContainer.selectAll("g.xAxis")
.data([1])
.join("g")
.attr("class", "xAxis")
.call(xAxisScatter);
circlesContainer.selectAll("text.chartTitle")
.data([1])
.join("text")
.attr("class", "chartTitle")
.attr("font-family", "sans-serif")
.attr("font-size", 14)
.attr("fill", "currentColor")
.attr("y", 30)
.attr("x", 10)
.text(`Average Fertility & Life Expectancy by Country in ${year}`);
}
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