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使用Javascript和d3库我已制作了英国(不包括NI)的选区地图,并添加了选择每个选区颜色的功能。我现在希望计算每种颜色的选区数量并将它们显示在条形图上。选区数据来自topojson文件。使用d3计算所选元素
有人可以告诉我如何做到这一点。非常感谢
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<style>
/* define style for map */
.constituency {
fill: black;
stroke: #fff;
stroke-width: 0.25px;
}
// .constituency.W28 { fill: red; }
</style>
</head>
<body>
<div id='map'></div>
<script src="http://d3js.org/d3.v3.min.js"></script>
<script src="http://d3js.org/topojson.v1.min.js"></script>
<script>
// create map
var width = 700,
height = 1000;
var projection = d3.geo.albers()
//.center([0, 55.4])
.center([3, 54])
.rotate([4.4, 0])
.parallels([50, 60])
.scale(4000)
.translate([width/2, height/2])
//.translate(200,200)
;
var path = d3.geo.path()
.projection(projection);
var svg = d3.select("#map").append("svg")
.attr("width", width)
.attr("height", height)
.call(d3.behavior.zoom().on('zoom', redraw))
.call(d3.behavior.zoom().on("dblclick.zoom", null)
;
function redraw() {
svg.attr('transform', 'translate(' + d3.event.translate + ') scale(' + d3.event.scale + ')');
}
var currentColor = "black";
var toggleColor = (function(){
var i=0;
var Colors = ["black","rgba(5, 117, 201, 1)", "rgba(237, 30, 14, 1)", "rgba(254, 131, 0, 1)", "rgba(235, 195, 28, 1)", "rgba(113, 47, 135, 1)", "rgba(120, 195, 30, 1)","rgba(78, 159, 47, 1)"];
return function(){
i=0;
if(currentColor != "rgba(120, 195, 30, 1)"){
while(currentColor != Colors[i]){
i++;
}
currentColor = Colors[i+1];
}
else{
currentColor = "black";
}
// currentColor = currentColor == "rgba(5, 117, 201, 1)" ? "rgba(237, 30, 14, 1)" : "rgba(5, 117, 201, 1)";
d3.select(this).style("fill", currentColor);
}
})();
d3.json("constituencies.topo.json", function(error, topology) {
// create a polygon for every constituency
svg.selectAll(".constituency")
// retrieve the features so that we can access the id
.data(topojson.feature(topology, topology.objects.constituencies).features)
.enter().append("path")
.attr("class", function(d) { return "constituency " + d.id; })
.attr("d", path)
.style("fill", "black")
.on("click", toggleColor)
});
</script>
</body>
</html>
非常感谢亚当,我偶然以同样的方式工作,但感谢您的帮助。我可以请你看看我的另一个问题,继续这段代码,我有一个HTML条形图,列出所有彩色选区的数组,但是在选择颜色后似乎没有重新绘制 – Hanros94
请确保你实际上将更新的数据附加到条上。要么删除所有现有的栏,并使用.data(byColor).enter()再次添加它们或使用选择.merge https://bl.ocks.org/mbostock/3808218 –