I solve real-world problems with design, programming, and critical business thinking skills.
Published
Edited
Feb 20, 2019
5 forks
11 stars
chart = {
// Area
const area = d3.area()
.x(d => xScale(d.date))
.y1(d => yScale(d.population))
.y0(yScale(0))
;
svg.append('path')
.attr('d', area(data))
.attr('stroke', '#147F90')
.attr('stroke-width', '2px')
.attr('fill', '#A6E8F2')
;
// Axis
const xAxis = d3.axisBottom()
.scale(xScale);
const xAxisTranslate = height - margin.bottom;
svg.append('g')
.attr('transform', `translate(0, ${xAxisTranslate})`)
.call(xAxis)
;
const yAxis = d3.axisLeft()
.tickFormat(d3.format('~s'))
.scale(yScale);
svg.append('g')
.attr('transform', `translate(${margin.left}, 0)`)
.call(yAxis)
;
// Interactivity
svg.append('line').classed('hoverLine', true)
svg.append('circle').classed('hoverPoint', true);
svg.append("text").classed('hoverText', true);
svg.append('rect')
.attr('fill', 'transparent')
.attr('x', 0)
.attr('y', 0)
.attr('width', width)
.attr('height', height)
;
svg.on('mousemove', mouseMove);
// Render
return svg.node();
}
svg = d3.select(DOM.svg(width, height));
xScale = {
const xExtent = d3.extent(data, d => d.date);
const xScale = d3.scaleTime()
.domain(xExtent)
.range([margin.left, width - margin.right]);
return xScale;
}
yScale = {
const yMax = d3.max(data, d => d.population);
const yMin = 0;
const yScale = d3.scaleLinear()
.domain([yMin, yMax])
.range([height - margin.bottom, margin.top]);
return yScale;
}
mouseMove = () => {
d3.event.preventDefault();
const mouse = d3.mouse(d3.event.target);
const [
xCoord,
yCoord,
] = mouse;
const mouseDate = xScale.invert(xCoord);
const mouseDateSnap = d3.timeYear.floor(mouseDate);
if (xScale(mouseDateSnap) < margin.left ||
xScale(mouseDateSnap) > width - margin.right) {
return;
}
const bisectDate = d3.bisector(d => d.date).right;
const xIndex = bisectDate(data, mouseDateSnap, 1);
const mousePopulation = data[xIndex].population;
svg.selectAll('.hoverLine')
.attr('x1', xScale(mouseDateSnap))
.attr('y1', margin.top)
.attr('x2', xScale(mouseDateSnap))
.attr('y2', height - margin.bottom)
.attr('stroke', '#147F90')
.attr('fill', '#A6E8F2')
;
svg.selectAll('.hoverPoint')
.attr('cx', xScale(mouseDateSnap))
.attr('cy', yScale(mousePopulation))
.attr('r', '7')
.attr('fill', '#147F90')
;
const isLessThanHalf = xIndex > data.length / 2;
const hoverTextX = isLessThanHalf ? '-0.75em' : '0.75em';
const hoverTextAnchor = isLessThanHalf ? 'end' : 'start';
svg.selectAll('.hoverText')
.attr('x', xScale(mouseDateSnap))
.attr('y', yScale(mousePopulation))
.attr('dx', hoverTextX)
.attr('dy', '-1.25em')
.style('text-anchor', hoverTextAnchor)
.text(d3.format('.5s')(mousePopulation));
};
One platform to build and deploy the best data apps
Experiment and prototype by building visualizations in live JavaScript notebooks. Collaborate with your team and decide which concepts to build out.
Use Observable Framework to build data apps locally. Use data loaders to build in any language or library, including Python, SQL, and R.
Seamlessly deploy to Observable. Test before you ship, use automatic deploy-on-commit, and ensure your projects are always up-to-date.