<!DOCTYPE html>
<meta charset="utf-8">
<head>
<title>Simple Line Graph using SVG and d3.js</title>
<script src="http://d3js.org/d3.v3.js"></script>
<script src="//ajax.googleapis.com/ajax/libs/jquery/2.0.3/jquery.min.js"></script>
<script src="json.js"></script>
<style>
/* tell the SVG path to be a thin blue line without any area fill */
svg {
border: 1px solid red;
}
.text-anchor{
font-size: 15px;
}
path {
stroke: steelblue;
stroke-width: 1;
fill: none;
}
.axis {
shape-rendering: crispEdges;
}
.x.axis line {
stroke: lightgrey;
}
.x.axis .minor {
stroke-opacity: .5;
}
.x.axis path {
display: none;
}
.y.axis line, .y.axis path {
fill: none;
stroke: #000;
}
</style>
</head>
<body>
<div id="graph" class="aGraph" style="position:absolute;top:0px;left:0; float:left;"></div>
<script>
/* implementation heavily influenced by http://bl.ocks.org/1166403 */
var json = ["{\"created_at\":1385481755,\"rankings\":[[\"#OBAMA\",91],[\"#TCOT\",65],[\"#OBAMACARE\",26],[\"#IRAN\",25],[\"#MTVSTARS\",20],[\"#BENGHAZI\",17],[\"#TEAPARTY\",16],[\"#LNYHBT\",12],[\"#PJNET\",11],[\"#CARAMEL\",11]]}","{\"created_at\":1385481749,\"rankings\":[[\"#OBAMA\",90],[\"#TCOT\",64],[\"#OBAMACARE\",26],[\"#IRAN\",25],[\"#MTVSTARS\",19],[\"#BENGHAZI\",17],[\"#TEAPARTY\",16],[\"#LNYHBT\",12],[\"#PJNET\",11],[\"#CARAMEL\",11]]}","{\"created_at\":1385481743,\"rankings\":[[\"#OBAMA\",90],[\"#TCOT\",64],[\"#OBAMACARE\",26],[\"#IRAN\",25],[\"#MTVSTARS\",18],[\"#BENGHAZI\",17],[\"#TEAPARTY\",16],[\"#LNYHBT\",12],[\"#PJNET\",11],[\"#CARAMEL\",11]]}","{\"created_at\":1385481737,\"rankings\":[[\"#OBAMA\",93],[\"#TCOT\",63],[\"#OBAMACARE\",28],[\"#IRAN\",27],[\"#MTVSTARS\",18],[\"#BENGHAZI\",17],[\"#TEAPARTY\",16],[\"#PJNET\",12],[\"#POPCORN\",11],[\"#CARAMEL\",11]]}","{\"created_at\":1385481731,\"rankings\":[[\"#OBAMA\",91],[\"#TCOT\",64],[\"#OBAMACARE\",29],[\"#IRAN\",27],[\"#MTVSTARS\",17],[\"#BENGHAZI\",17],[\"#TEAPARTY\",15],[\"#POPCORN\",11],[\"#CARAMEL\",11],[\"#IMMIGRATION\",11]]}","{\"created_at\":1385481725,\"rankings\":[[\"#OBAMA\",61],[\"#TCOT\",63],[\"#OBAMACARE\",28],[\"#IRAN\",26],[\"#MTVSTARS\",17],[\"#BENGHAZI\",16],[\"#TEAPARTY\",13],[\"#IMMIGRATION\",11],[\"#CARAMEL\",11],[\"#POPCORN\",11]]}","{\"created_at\":1385481719,\"rankings\":[[\"#OBAMA\",93],[\"#TCOT\",64],[\"#OBAMACARE\",28],[\"#IRAN\",26],[\"#MTVSTARS\",18],[\"#BENGHAZI\",16],[\"#TEAPARTY\",13],[\"#IMMIGRATION\",12],[\"#CARAMEL\",11],[\"#POPCORN\",11]]}","{\"created_at\":1385481713,\"rankings\":[[\"#OBAMA\",93],[\"#TCOT\",33],[\"#OBAMACARE\",28],[\"#IRAN\",26],[\"#MTVSTARS\",18],[\"#BENGHAZI\",16],[\"#TEAPARTY\",13],[\"#IMMIGRATION\",12],[\"#POPCORN\",11],[\"#CARAMEL\",11]]}","{\"created_at\":1385481707,\"rankings\":[[\"#OBAMA\",94],[\"#TCOT\",66],[\"#IRAN\",28],[\"#OBAMACARE\",28],[\"#MTVSTARS\",18],[\"#BENGHAZI\",16],[\"#TEAPARTY\",13],[\"#IMMIGRATION\",12],[\"#CARAMEL\",11],[\"#PJNET\",11]]}","{\"created_at\":1385481701,\"rankings\":[[\"#OBAMA\",94],[\"#TCOT\",66],[\"#IRAN\",28],[\"#OBAMACARE\",28],[\"#MTVSTARS\",16],[\"#BENGHAZI\",16],[\"#TEAPARTY\",13],[\"#PJNET\",12]]}"];
//parse json
$.each(json,function(index,value){
json[index]= JSON.parse(value);
});
var startTime = new Date(1385481173);
var endTime = new Date(1385481173+6000);
var timeStep = 300000;
// define dimensions of graph
var m = [80, 80, 80, 80]; // margins
var w = 1000 - m[1] - m[3]; // width
var h = 400 - m[0] - m[2]; // height
//specify ranges and domains
var x = d3.time.scale().domain([d3.min(json,function (d){return d.created_at}),
d3.max(json,function (d){return d.created_at})]).range([0, w]);
var y = d3.scale.linear().domain([0, d3.max(json, function (d) {
return Math.max(d.rankings[0][1],d.rankings[1][1]);
})]).range([h, 0]);
var line = d3.svg.line()
// assign the X function to plot our line as we wish
.x(function(d,i) {
//console.log(d);
//console.log('Plotting X value for data point to be at: ' + d.created_at + ' using our xScale.');
return x(d.created_at);
})
.y(function(d) {
//console.log('Plotting Y value for data point to be at:' + d.rankings[0][1] + " using our yScale.");
return y(d.rankings[0][1]);
})
// Add an SVG element with the desired dimensions and margin.
var graph = d3.select("#graph").append("svg:svg")
.attr("width", w + m[1] + m[3])
.attr("height", h + m[0] + m[2])
.append("svg:g")
.attr("transform", "translate(" + m[3] + "," + m[0] + ")");
// create yAxis
var xAxis = d3.svg.axis().scale(x).tickSize(-h).tickFormat(d3.time.format("%H:%M:%S"));
// Add the x-axis.
graph.append("svg:g")
.attr("class", "x axis")
.attr("transform", "translate(0," + h + ")")
.call(xAxis)
.selectAll("text")
.attr("class","text-anchor")
.attr("dx", "-2.48em")
.attr("dy", ".15em")
.attr("transform", function(d) {
return "rotate(-65)"
});
// create left yAxis
var yAxisLeft = d3.svg.axis().scale(y).ticks(9).orient("left");
// Add the y-axis to the left
graph.append("svg:g")
.attr("class", "y axis")
// .attr("transform", "translate(-25,0)")
.call(yAxisLeft);
// Add the line by appending an svg:path element with the data line we created above
// do this AFTER the axes above so that the line is above the tick-lines
graph.append("svg:path").attr("d", line(json));
</script>
</body>
</html>
我试图在X轴上只显示几小时：分钟：秒，但似乎d3没有正确转换它，它做错了什么？
答案 0 :(得分：1)
问题是Javascript中的日期是自Epoch以来的毫秒，而不是秒。 JSON中的日期以秒为单位，因此您需要乘以1000：
var x = d3.time.scale().domain([d3.min(json,function (d){return d.created_at * 1000}),
d3.max(json,function (d){return d.created_at * 1000})]).range([0, w]);
// ...
line.x(function(d,i) {
return x(d.created_at * 1000);
})
完成jsfiddle here。
一般情况下，您可以分别使用d3.extent()代替min和max：
var x = d3.time.scale().domain(d3.extent(json,function (d){return d.created_at * 1000}))
.range([0, w]);