line chart of json data in d3

问题

I am learning d3. I want to make a line chart using json data. The data I am using is:

var data = [
    { "at": "2014-11-18T07:29:03.859Z", "value": 0.553292},
    { "at": "2014-11-18T07:28:53.859Z", "value": 0.563292},
    { "at": "2014-11-18T07:28:43.859Z", "value": 0.573292},
    { "at": "2014-11-18T07:28:33.859Z", "value": 0.583292},
    { "at": "2014-11-18T07:28:13.859Z", "value": 0.553292},
    { "at": "2014-11-18T07:28:03.859Z", "value": 0.563292}];

I want "at" on x axis and "value" on y axis. Also I need to parse the "at" as time only. Please provide me pointers how i will proceed further. The code till now I have implemented is below. I tried to look for documentation for this but found none.

<html>
    <head>
        <title>line chart on json</title>
        <script src="http://d3js.org/d3.v2.js"></script>
        <style>
            /* tell the SVG path to be a thin blue line without any area fill */
            path {
                stroke: steelblue;
                stroke-width: 1;
                fill: none;
            }
        </style>
    </head>
    <body>

    <script>

    var width = 400;
    var height = 150;

    var data = [
    { "at": "2014-11-18T07:29:03.859Z", "value": 0.553292},
    { "at": "2014-11-18T07:28:53.859Z", "value": 0.563292},
    { "at": "2014-11-18T07:28:43.859Z", "value": 0.573292},
    { "at": "2014-11-18T07:28:33.859Z", "value": 0.583292},
    { "at": "2014-11-18T07:28:13.859Z", "value": 0.553292},
    { "at": "2014-11-18T07:28:03.859Z", "value": 0.563292}]; 

    var x = d3.scale.ordinal(); 

    var y = d3.scale.linear().range([height, 0]);
    var xAxis = d3.svg.axis().scale(x).orient("bottom"); 
    var line = d3.svg.line()
        .x(function(d) { return x(d.at);})
        .y(function(d) { return y(d.value); })
        .interpolate("linear")
    var graph = d3.select(graph1).append("svg:svg").attr("width", "300").  attr("height", "150");
    function make_y_axis() {
        return d3.svg.axis().scale(y).orient("left").ticks(5)
    }

    </script>

    </body>
</html>

回答1:

Look at this example http://bl.ocks.org/crayzeewulf/9719255

There used 2 graphs, but you can use just one and place data as you want.

As for date you can look at this example http://jsfiddle.net/robdodson/KWRxW/, xAxis in particular.

var xAxis = d3.svg.axis()
    .scale(x)
    .orient('bottom')
    .ticks(d3.time.days, 1)
    .tickFormat(d3.time.format('%a %d'))
    .tickSize(0)
    .tickPadding(8);

回答2:

What is graph1 in the below line:

var graph = d3.select(graph1).append("svg:svg").attr("width", "300"). attr("height", "150");

来源：https://stackoverflow.com/questions/27148545/line-chart-of-json-data-in-d3

标签

javascript

json

d3.js