具有单个Y值的D3图随时间变化

Question

我的数据在多个日期都有一个常量值。

[{"date":"13-Sep-15","data0":2464},{"date":"12-Sep-15","data0":2464},
{"date":"11-Sep-15","data0":2464},{"date":"10-Sep-15","data0":2464},
{"date":"9-Sep-15","data0":2464},{"date":"8-Sep-15","data0":2464},
{"date":"7-Sep-15","data0":2464}]

d3.axis（）有什么设置来获取这样的图形？

这需要从1＆gt; n y值开始工作。 无论.domain的价值如何，[2464, 2464]都不喜欢.ticks的范围。

Answer 1

好的我假设，希望根据数据中的值有明显的y刻度。

我正在做这样的事情来获得y轴所需的唯一标记：

var yData = [];

data.forEach(function (d) {
    d.date = parseDate(d.date);
    d.close = +d.data0;
    yData.push(+d.data0)
});
yData = d3.set(yData).values();//get a set of values for y axis.

此处的完整代码：

// Set the dimensions of the canvas / graph
var margin = {
    top: 30,
    right: 20,
    bottom: 30,
    left: 50
},
width = 600 - margin.left - margin.right,
    height = 270 - margin.top - margin.bottom;

// Parse the date / time
var parseDate = d3.time.format("%d-%b-%y").parse;

// Set the ranges
var x = d3.time.scale().range([0, width]);
var y = d3.scale.linear().range([height, 0]);



// Define the line
var valueline = d3.svg.line()
    .x(function (d) {
    return x(d.date);
})
    .y(function (d) {
    return y(d.close);
});

// Adds the svg canvas
var svg = d3.select("body")
    .append("svg")
    .attr("width", width + margin.left + margin.right)
    .attr("height", height + margin.top + margin.bottom)
    .append("g")
    .attr("transform",
    "translate(" + margin.left + "," + margin.top + ")");


data = [{
    "date": "13-Sep-15",
    "data0": 2464
}, {
    "date": "12-Sep-15",
    "data0": 2464
}, {
    "date": "11-Sep-15",
    "data0": 2464
}, {
    "date": "10-Sep-15",
    "data0": 2464
}, {
    "date": "9-Sep-15",
    "data0": 2464
}, {
    "date": "8-Sep-15",
    "data0": 2464
}, {
    "date": "7-Sep-15",
    "data0": 2464
}];
var yData = [];

data.forEach(function (d) {
    d.date = parseDate(d.date);
    d.close = +d.data0;
    yData.push(+d.data0)
});
yData = d3.set(yData).values()
// Define the axes
var xAxis = d3.svg.axis().scale(x)
    .orient("bottom").ticks(5);

var yAxis = d3.svg.axis().scale(y)
    .orient("left").tickValues(yData);
// Scale the range of the data
x.domain(d3.extent(data, function (d) {
    return d.date;
}));
y.domain([0, d3.max(data, function (d) {
    return d.close;
})]);

// Add the valueline path.
svg.append("path")
    .attr("class", "line")
    .attr("d", valueline(data));

// Add the X Axis
svg.append("g")
    .attr("class", "x axis")
    .attr("transform", "translate(0," + height + ")")
    .call(xAxis);

// Add the Y Axis
svg.append("g")
    .attr("class", "y axis")
    .call(yAxis);

body {
    font: 12px Arial;
}
path {
    stroke: steelblue;
    stroke-width: 2;
    fill: none;
}
.axis path, .axis line {
    fill: none;
    stroke: grey;
    stroke-width: 1;
    shape-rendering: crispEdges;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.4.11/d3.min.js"></script>

希望这有帮助！

Answer 2

想出来。以下是以y为中心的图表。

// Set the dimensions of the canvas / graph
var margin = {
    top: 30,
    right: 20,
    bottom: 30,
    left: 50
  },
  width = 600 - margin.left - margin.right,
  height = 270 - margin.top - margin.bottom;

// Parse the date / time
var parseDate = d3.time.format("%d-%b-%y").parse;

// Set the ranges
var x = d3.time.scale().range([0, width]);
var y = d3.scale.linear().range([height, 0]);

// Define the line
var valueline = d3.svg.line()
  .x(function(d) {
    return x(d.date);
  })
  .y(function(d) {
    return y(d.close) / 2;
  });

// Adds the svg canvas
var svg = d3.select("body")
  .append("svg")
  .attr("width", width + margin.left + margin.right)
  .attr("height", height + margin.top + margin.bottom)
  .append("g")
  .attr("transform",
    "translate(" + margin.left + "," + margin.top + ")");


data = [{
  "date": "13-Sep-15",
  "data0": 2464
}, {
  "date": "12-Sep-15",
  "data0": 2464
}, {
  "date": "11-Sep-15",
  "data0": 2464
}, {
  "date": "10-Sep-15",
  "data0": 2464
}, {
  "date": "9-Sep-15",
  "data0": 2464
}, {
  "date": "8-Sep-15",
  "data0": 2464
}, {
  "date": "7-Sep-15",
  "data0": 2464
}];
var yData = [];

data.forEach(function(d) {
  d.date = parseDate(d.date);
  d.close = +d.data0;
  yData.push(+d.data0)
});
yData = d3.set(yData).values()
  // Define the axes
var xAxis = d3.svg.axis().scale(x)
  .orient("bottom").ticks(5);

var yAxis = d3.svg.axis().scale(y)
  .orient("left").tickValues(yData);
// Scale the range of the data
x.domain(d3.extent(data, function(d) {
  return d.date;
}));
y.domain(d3.extent(data, function(d) {
  return d.close;
}));

// Add the valueline path.
svg.append("path")
  .attr("class", "line")
  .attr("d", valueline(data));

// Add the X Axis
svg.append("g")
  .attr("class", "x axis")
  .attr("transform", "translate(0," + height + ")")
  .call(xAxis);

// Add the Y Axis
svg.append("g")
  .attr("class", "y axis")
  .call(yAxis);
d3.select('.y .tick').attr("transform", "translate(0," + height / 2 + ")");

body {
  font: 12px Arial;
}
path {
  stroke: steelblue;
  stroke-width: 2;
  fill: none;
}
.axis path,
.axis line {
  fill: none;
  stroke: grey;
  stroke-width: 1;
  shape-rendering: crispEdges;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.4.11/d3.min.js"></script>

的变化：

将y向下翻译为高度/ 2：

d3.select('.y .tick').attr("transform", "translate(0," + height / 2 + ")");

更改了范围：

y.domain(d3.extent(data, function (d) {
    return d.close;
}));

该行的y减半：

var valueline = d3.svg.line()
    .x(function (d) {
    return x(d.date);
})
.y(function (d) {
    return y(d.close) / 2;
});