map3

[梵总]

var items = [
   '#cc0000','#00cc00', '#0000cc'
];


for(var i=0; i < 100; i++ ) {

	let nlayer = svg.append('g');

	let color = items[Math.floor(Math.random() * items.length)];
	if (i<10){
		j = "00" + i;
	}
	else {
		j = "0" + i;
	}

	console.log(j, color);
	d3.json("https://api.deniapps.com/zip3?zip3="+j, function(json) {
	const features = json.data;
	nlayer.selectAll("path")
	.data(features)
	.enter()
	.append("path")
	.attr("d", path)
	.style("stroke", "#ccc")
	.style("stroke-width", "1")
	.style("fill", color)

});

}

[梵总]

This is amazing website for geoJSON topoJSON, shape and beyond:
https://mapshaper.org/

[梵总]

Start from here for some basic example using D3:
http://bl.ocks.org/michellechandra/0b2ce4923dc9b5809922