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denisemauldin/index.html

Created June 29, 2017 15:38
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d3 v4 topojson clickable map
Raw
index.html
<!DOCTYPE html>
<style>
.counties :hover {
fill: red;
}
.county-borders {
fill: none;
stroke: #fff;
stroke-width: 0.5px;
stroke-linejoin: round;
stroke-linecap: round;
pointer-events: none;
}
</style>
<svg width="960" height="600"></svg>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script src="https://d3js.org/topojson.v2.min.js"></script>
<script>
var svg = d3.select("svg");
var path = d3.geoPath();
d3.json("https://d3js.org/us-10m.v1.json", function(error, us) {
if (error) throw error;
svg.append("g")
.attr("class", "counties")
.selectAll("path")
.data(topojson.feature(us, us.objects.counties).features)
.enter().append("path")
.attr("d", path);
// the following block is new, adding JS events
let hoverEnabled = false;
svg.on('mousedown', x => hoverEnabled = true)
.on('mouseup', x => hoverEnabled = false)
svg.selectAll('.counties path').on('mouseover', function() {
if (hoverEnabled) {
this.classList.add('hovered');
}
});
svg.append("path")
.attr("class", "county-borders")
.attr("d", path(topojson.mesh(us, us.objects.counties, function(a, b) { return a !== b; })));
});
</script>
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