I am trying to create a grouped bar chart using D3.js. I have followed the examples provided in the D3 wiki at GitHub and have a semi working graph. However, it seems like all datapoints for a certain value get plotted at the same spot.
my data looks is a JSON array, which looks like this
[{"experiment":30385,"c":1,"ratio":0.022,"stdev":0.363,"median":0.032,"zscore":6.359},
{"experiment":30385,"c":2,"ratio":-0.02,"stdev":0.351,"median":-0.005,"zscore":-4.786},
{"experiment":30385,"c":3,"ratio":0.074,"stdev":0.339,"median":0.089,"zscore":29.036},
{"experiment":30385,"c":4,"ratio":-0.077,"stdev":0.361,"median":-0.065,"zscore":-25.704},
{"experiment":30385,"c":5,"ratio":-0.354,"stdev":0.569,"median":-0.223,"zscore":-145.625},
{"experiment":30385,"c":6,"ratio":-0.02,"stdev":0.352,"median":-0.007,"zscore":-2.545},
{"experiment":30385,"c":7,"ratio":0.018,"stdev":0.346,"median":0.036,"zscore":7.412},
{"experiment":30385,"c":8,"ratio":-0.11,"stdev":0.348,"median":-0.096,"zscore":-37.69},
{"experiment":30385,"c":9,"ratio":-0.012,"stdev":0.357,"median":0.008,"zscore":-4.394},
{"experiment":30385,"c":10,"ratio":-0.054,"stdev":0.366,"median":-0.036,"zscore":-14.158},
{"experiment":30385,"c":11,"ratio":-0.071,"stdev":0.344,"median":-0.044,"zscore":-21.4},
{"experiment":30385,"c":12,"ratio":-0.01,"stdev":0.352,"median":0.002,"zscore":-1.467},
{"experiment":30385,"c":13,"ratio":-0.03,"stdev":0.366,"median":-0.014,"zscore":-2.375},
{"experiment":30385,"c":14,"ratio":-0.039,"stdev":0.339,"median":-0.025,"zscore":-8.816},
{"experiment":30385,"c":15,"ratio":-0.02,"stdev":0.357,"median":0.0065,"zscore":-4.2},
{"experiment":30385,"c":16,"ratio":0.449,"stdev":0.439,"median":0.4215,"zscore":69.859},
{"experiment":30385,"c":17,"ratio":-0.028,"stdev":0.367,"median":-0.007,"zscore":-4.9},
{"experiment":30385,"c":18,"ratio":-0.071,"stdev":0.357,"median":-0.061,"zscore":-17.268},
{"experiment":30385,"c":19,"ratio":0.143,"stdev":0.356,"median":0.1415,"zscore":13.961},
{"experiment":30385,"c":20,"ratio":0.022,"stdev":0.349,"median":0.0405,"zscore":3.462},
{"experiment":30385,"c":21,"ratio":-0.076,"stdev":0.335,"median":-0.086,"zscore":-11.368},
{"experiment":30385,"c":22,"ratio":0.038,"stdev":0.355,"median":0.07,"zscore":3.152},
{"experiment":30385,"c":23,"ratio":0,"stdev":0,"median":0,"zscore":3.152},
{"experiment":30385,"c":24,"ratio":0,"stdev":0,"median":0,"zscore":3.152},
{"experiment":30384,"c":1,"ratio":-0.058,"stdev":0.403,"median":-0.042,"zscore":-14.154},
{"experiment":30384,"c":2,"ratio":-1.017,"stdev":0.418,"median":-0.982,"zscore":-360.857},
{"experiment":30384,"c":3,"ratio":-0.094,"stdev":0.417,"median":-0.074,"zscore":-30.964},
{"experiment":30384,"c":4,"ratio":-0.155,"stdev":0.397,"median":-0.157,"zscore":-54.593},
{"experiment":30384,"c":5,"ratio":-0.024,"stdev":0.381,"median":-0.001,"zscore":-8.125},
{"experiment":30384,"c":6,"ratio":0.013,"stdev":0.37,"median":0.0245,"zscore":7.455},
{"experiment":30384,"c":7,"ratio":-0.2,"stdev":0.434,"median":-0.171,"zscore":-56.706},
{"experiment":30384,"c":8,"ratio":-0.017,"stdev":0.367,"median":0.003,"zscore":-5.621},
{"experiment":30384,"c":9,"ratio":0.025,"stdev":0.365,"median":0.044,"zscore":6.818},
{"experiment":30384,"c":10,"ratio":-0.168,"stdev":0.422,"median":-0.121,"zscore":-44.158},
{"experiment":30384,"c":11,"ratio":-0.073,"stdev":0.382,"median":-0.056,"zscore":-22.067},
{"experiment":30384,"c":12,"ratio":0.002,"stdev":0.379,"median":0.019,"zscore":2.533},
{"experiment":30384,"c":13,"ratio":-0.054,"stdev":0.39,"median":-0.0295,"zscore":-8.375},
{"experiment":30384,"c":14,"ratio":0.019,"stdev":0.376,"median":0.025,"zscore":6.447},
{"experiment":30384,"c":15,"ratio":-0.054,"stdev":0.421,"median":-0.0265,"zscore":-11},
{"experiment":30384,"c":16,"ratio":0.055,"stdev":0.375,"median":0.0695,"zscore":8.297},
{"experiment":30384,"c":17,"ratio":0.024,"stdev":0.394,"median":0.054,"zscore":3.767},
{"experiment":30384,"c":18,"ratio":-0.049,"stdev":0.36,"median":-0.018,"zscore":-11.902},
{"experiment":30384,"c":19,"ratio":0.095,"stdev":0.37,"median":0.1135,"zscore":10.24},
{"experiment":30384,"c":20,"ratio":0.157,"stdev":0.343,"median":0.174,"zscore":29.423},
{"experiment":30384,"c":21,"ratio":-0.091,"stdev":0.407,"median":-0.067,"zscore":-14},
{"experiment":30384,"c":22,"ratio":0.071,"stdev":0.381,"median":0.104,"zscore":7.329},
{"experiment":30384,"c":23,"ratio":0,"stdev":0,"median":0,"zscore":7.329},
{"experiment":30384,"c":24,"ratio":0,"stdev":0,"median":0,"zscore":7.329}]
The data contains an experiment id, chromosome number, ratio and some satistics. The array can contain data from various experiments, which all have a different id.
my js code currently looks like this:
<script>
function unique(list) {
var result = [];
$.each(list, function(i, e) {
if ($.inArray(e, result) == -1) result.push(e);
});
return result;
}
var margin = {top: 50, right: 50, bottom: 50, left: 50};
var width = 1000 - margin.left - margin.right;
var height = 500 - margin.top - margin.bottom;
var threshold={upper:0.1,lower:-0.1};
var x0 = d3.scale.ordinal()
.rangeRoundBands([0, width], .1);
var x1 = d3.scale.ordinal();
var y = d3.scale.linear()
.range([height, 0]);
var color = d3.scale.ordinal()
.range(["#98abc5", "#8a89a6", "#7b6888", "#6b486b", "#a05d56", "#d0743c", "#ff8c00"]);
var xAxis = d3.svg.axis()
.scale(x0)
.orient("bottom");
var yAxis = d3.svg.axis()
.scale(y)
.orient("left");
var svg = d3.select("#svg").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 + ")");
d3.json("{{settings.Base_url}}/templates/addons/data.json", function(error, data) {
if (error) throw error;
var expNames =unique(data.map(function(d) { return d.experiment; }));
x0.domain(data.map(function(d) { return d.c; }));
x1.domain(expNames).rangeRoundBands([0, x0.rangeBand()]);
y.domain([-1.5,1.5]);
svg.append("g")
.attr("class", "x axis")
.attr("transform", "translate(0," + height + ")")
.call(xAxis);
svg.append("g")
.attr("class", "y axis")
.call(yAxis)
.append("text")
.attr("transform", "rotate(-90)")
.attr("y", -50)
.attr("dy", ".71em")
.style("text-anchor", "end")
.text("Average Ratio/Chromosome");
var chr = svg.selectAll(".bar")
.data(data)
.enter().append("g")
.attr("class", "bar")
.attr("transform", function(d) { return "translate(" + x0(d.c) + ",0)"; });
chr.selectAll("rect")
.data(data)
.enter().append("rect")
.attr("x", function(d) {return x1(d.experiment);})
.attr("y", function(d) { return y(Math.max(0, d.ratio)); })
.attr("height", function(d) { return Math.abs(y(d.ratio)-y(0)); })
.attr("width", x1.rangeBand())
.style("fill", function(d) { return color(d.experiment); })
.style({"opacity":0.6,"stroke-width":"2"})
.text("test");
var legend = svg.selectAll(".legend")
.data(expNames.slice().reverse())
.enter().append("g")
.attr("class", "legend")
.attr("transform", function(d, i) { return "translate(0," + i * 20 + ")"; });
legend.append("rect")
.attr("x", width - 18)
.attr("width", 18)
.attr("height", 18)
.style("fill", color);
legend.append("text")
.attr("x", width - 24)
.attr("y", 9)
.attr("dy", ".35em")
.style("text-anchor", "end")
.text(function(d) { return d; });
});
</script>
which results in a graph like this:
any ideas? I have a general idea where the error is, but cant seem to find a solution.
Note sure if I understand the question properly, but here's what I get:
You bind the data to the groups which you transform in x direction.
Afterwards you want to display two bars (for each experiment) in each group (c value)
If that's the case, you don't need to bind the data again for the bars, so it's just:
var chr = svg.selectAll(".bar")
.data(data)
.enter().append("g")
.attr("class", "bar")
.attr("transform", function (d) {
return "translate(" + x0(d.c) + ",0)";
});
chr.append("rect")
.attr("x", function (d) {
return x1(d.experiment);
})
...etc
See fiddle
Does that help?
i created a stacked bar graph.
on the y axis side i have ticks with varying lengths.
what i am trying to accomplish is to align the text in the tick to the left.
this is my example:http://jsfiddle.net/2khbceut/2/
html
<title>Diverging Stacked Bar Chart with D3.js</title>
<body>
<div id="figure" align="center" style="margin-bottom: 50px;"></div>
</body>
javascript
$(document).ready(getTopolegy());
function getTopolegy(){
var data = null;
var links = parseTopology(data);
createChart(links);
}
function parseTopology(data){
var links=[{1:5,2:5,3:10,N:20,link_name: "Link CHGIL21CRS-SFXCA21CRS"},
{1:5,2:5,3:10,N:20,link_name: "Link NYCNY21CRS-NYCNY22CRS"}];
return links;
}
function jsonNameToId(name){
switch (allocated_priority) {
case "allocated_priority":
return 1;
case "allocated_default":
return 2;
case "spare_capacity":
return 3;
case "total":
return "N";
default:
return 999;
}
}
function createChart(data){
var margin = {top: 50, right: 20, bottom: 10, left: 210},
width = 1000 - margin.left - margin.right,
height = 100 - margin.top - margin.bottom;
var y = d3.scale.ordinal()
.rangeRoundBands([0, height], .3);
var x = d3.scale.linear()
.rangeRound([0, width]);
var color = d3.scale.ordinal()
.range(["#cccccc", "#92c6db", "#086fad"]);
var xAxis = d3.svg.axis()
.scale(x)
.orient("top");
var yAxis = d3.svg.axis()
.scale(y)
.orient("left")
var svg = d3.select("#figure").append("svg")
.attr("width", width + margin.left + margin.right)
.attr("height", height + margin.top + margin.bottom)
.attr("id", "d3-plot")
.append("g")
.attr("transform", "translate(" + margin.left + "," + margin.top + ")");
color.domain(["Allocated Priority %", "Allocated Default %", "Spare Capacity %"]);
// d3.csv("js/raw_data.csv", function(error, data) {
data.forEach(function(d) {
d["Allocated Priority %"] = +d[1]*100/d.N;
d["Allocated Default %"] = +d[2]*100/d.N;
d["Spare Capacity %"] = +d[3]*100/d.N;
var x0 = 0;
var idx = 0;
d.boxes = color.domain().map(function(name) { return {name: name, x0: x0, x1: x0 += +d[name], N: +d.N, n: +d[idx += 1]}; });
});
var min_val = d3.min(data, function(d) {
return d.boxes["0"].x0;
});
var max_val = d3.max(data, function(d) {
return d.boxes["2"].x1;
});
x.domain([min_val, max_val]).nice();
y.domain(data.map(function(d) { return d.link_name; }));
svg.append("g")
.attr("class", "x axis")
.call(xAxis);
svg.append("g")
.attr("class", "y axis")
.call(yAxis)
var vakken = svg.selectAll(".Link")
.data(data)
.enter().append("g")
.attr("class", "bar")
.attr("transform", function(d) { return "translate(0," + y(d.link_name) + ")"; });
var bars = vakken.selectAll("rect")
.data(function(d) { return d.boxes; })
.enter().append("g").attr("class", "subbar");
bars.append("rect")
.attr("height", y.rangeBand())
.attr("x", function(d) { return x(d.x0); })
.attr("width", function(d) { return x(d.x1) - x(d.x0); })
.style("fill", function(d) { return color(d.name); });
bars.append("text")
.attr("x", function(d) { return x(d.x0); })
.attr("y", y.rangeBand()/2)
.attr("dy", "0.5em")
.attr("dx", "0.5em")
.style("font" ,"10px sans-serif")
.style("text-anchor", "begin")
.text(function(d) { return d.n !== 0 && (d.x1-d.x0)>3 ? d.n : "" });
vakken.insert("rect",":first-child")
.attr("height", y.rangeBand())
.attr("x", "1")
.attr("width", width)
.attr("fill-opacity", "0.5")
.style("fill", "#F5F5F5")
.attr("class", function(d,index) { return index%2==0 ? "even" : "uneven"; });
svg.append("g")
.attr("class", "y axis")
.append("line")
.attr("x1", x(0))
.attr("x2", x(0))
.attr("y2", height);
var startp = svg.append("g").attr("class", "legendbox").attr("id", "mylegendbox");
// this is not nice, we should calculate the bounding box and use that
var legend_tabs = [0, 150, 300];
var legend = startp.selectAll(".legend")
.data(color.domain().slice())
.enter().append("g")
.attr("class", "legend")
.attr("transform", function(d, i) { return "translate(" + legend_tabs[i] + ",-45)"; });
legend.append("rect")
.attr("x", 0)
.attr("width", 18)
.attr("height", 18)
.style("fill", color);
legend.append("text")
.attr("x", 22)
.attr("y", 9)
.attr("dy", ".35em")
.style("text-anchor", "begin")
.style("font" ,"10px sans-serif")
.text(function(d) { return d; });
d3.selectAll(".axis path")
.style("fill", "none")
.style("stroke", "#000")
.style("shape-rendering", "crispEdges")
d3.selectAll(".axis line")
.style("fill", "none")
.style("stroke", "#000")
.style("shape-rendering", "crispEdges")
var movesize = width/2 - startp.node().getBBox().width/2;
d3.selectAll(".legendbox").attr("transform", "translate(" + movesize + ",0)");
// });
}
as can be seen the current positioning of the tick text is to the right.
i tried the following idea:
svg.append("g")
.attr("class", "y axis")
.call(yAxis)
.selectAll("text")
.style("text-anchor", "start");
but it did not position the ticks in the desired alignment.
any ideas?
You can make the Y axis right-oriented, which will have the effect of positioning all the labels to the right of the axis, left-aligning them:
var yAxis = d3.svg.axis()
.scale(y)
.orient("right")// <- 1st step
At that point the labels would disappear, because they'll get covered up by the bars of the graph.
But then you can shift all those left-aligned labels some constant distance in the negative X direction, such that they're back on the left side of the Y axis, but still left-aligned the way you wanted. tickPadding() is a way to shift them:
var yAxis = d3.svg.axis()
.scale(y)
.orient("right")
.tickPadding(-180)
Here's your example, modified with the above: http://jsfiddle.net/2khbceut/3/
Maybe hardcoding the -180 is ok for you. If you need that amount to be dynamic, you can compute it using getBBox() on each text element of the axis and taking the maximum width to be the negative offset.
You can set the text-anchor to "start" and adjust the x position with translate, I added the code below in the chart model "boxPlotChart.js"
g.select('.nv-y.nv-axis').selectAll('.tick').selectAll('text')
.style('text-anchor','start')
.attr('transform', function(d,i,j) { return 'translate(-14,0)' });
g.select('.nv-y.nv-axis').selectAll('.nv-axisMaxMin').selectAll('text')
.style('text-anchor','start')
.attr('transform', function(d,i,j) { return 'translate(-16,0)' });
I've somehow managed to do create a stacked bar chart for this post.
Instead of hover method i've chosen to get on with click event as i was facing some bug with the hover event like the elements were not disappearing properly when i hover on to a element.
When i click on a bar all the bars are getting disappeared and the width of the bar is getting increased. But that when I click on the bar that's been expanded i want to reset it's width to the original width.
I wanted to know how to get back to it's original width[when i was using hover method i defined the width manually]
Need to how to code for the send click event for the expanded bar.
Please help.
JS :
var width = 750,
height = 500;
var x = d3.scale.ordinal()
.rangeRoundBands([0, width], .1);
var y = d3.scale.linear()
.rangeRound([height, 0]);
var color = d3.scale.ordinal()
.range(["#D70B16", "#154CEF", "#1A8A55"]);
var xAxis = d3.svg.axis()
.scale(x)
.orient("bottom");
var yAxis = d3.svg.axis()
.scale(y)
.orient("left")
.tickFormat(d3.format(".2s"));
var svgContainer = d3.select("body")
.append("svg")
.attr("width", width)
.attr("height", height)
.append("g")
.attr("transform", "translate(" + 30 + "," + 30 + ")");
function movein() {
var allRect = d3.selectAll("rect")
// .transition()
// .duration(300)
.attr("opacity", 0)
.attr("display", "none")
d3.select(this)
.attr("opacity", 1)
.attr("display", "block")
d3.select(this)
.transition()
.delay(300)
.duration(500)
.attr("width", 300)
};
function moveout() {
d3.select(this)
.transition()
.duration(1000)
.attr("width", 150)
var allRect = d3.selectAll("rect")
.transition()
.delay(1000)
.duration(300)
.attr("opacity", 1)
.attr("display", "block")
};
d3.csv("data.csv", function(error, data) {
color.domain(d3.keys(data[0]).filter(function(key) { return key !== "circle"; }));
data.forEach(function(d) {
var y0 = 0;
d.hours = color.domain().map(function(name) { return {name: name, y0: y0, y1: y0 += +d[name]}; });
d.total = d.hours[d.hours.length - 1].y1;
});
x.domain(data.map(function(d) {return d.circle;}));
y.domain([0, d3.max(data, function(d) {return d.total;})])
svgContainer.append("g")
.attr("class", "x axis")
.attr("transform", "translate(0," + height + ")")
.call(xAxis);
svgContainer.append("g")
.attr("class", "y axis")
.call(yAxis)
.append("text")
.attr("transform", "rotate(-90)")
.attr("y", 6)
.attr("dy", ".71em")
.style("text-anchor", "end")
.text("Login Hours");
var circle = svgContainer.selectAll(".circle")
.data(data)
.enter().append("g")
.attr("class", "g")
.attr("transform", function(d) { return "translate(" + x(d.circle) + ",0)"; });
circle.selectAll("rect")
.data(function(d) { return d.hours; })
.enter()
.append("rect")
.attr("width", x.rangeBand())
.attr("y", function(d) { return y(d.y1); })
.attr("height", function(d) { return y(d.y0) - y(d.y1); })
.on("click", movein)
.on("click", moveout)
.style("fill", function(d) { return color(d.name); });
})
DATA :
state,value1, value2, value3
state1, 80, 10, 20
state2, 90, 5, 10
state3, 70, 15, 35
state4, 90, 3, 27
state5, 50, 25, 55
state6, 85, 8, 27
I have a basic line graph with two lines. When I click a button, one of the two lines will draw on the graph.
I use stroke-dasharray to draw the lines.
Would anyone know how I could add tooltips to my lines?
Does using stroke-dasharray make it harder?
Heres my code.
var button=d3.select("#button");
//defines canvas (area in which graph is placed)
var margin = {top: 30, right: 20, bottom: 50, left: 60},
width = 800 - margin.left - margin.right,
height = 700 - margin.top - margin.bottom;
var parseDate = d3.time.format("%d-%b-%y").parse;
//OUTPUT RANGE
var x = d3.time.scale()
.range([0, width]);
//OUTPUT RANGE
var y = d3.scale.linear()
.range([height, 0]);
var xAxis = d3.svg.axis().scale(x)
.orient("bottom")
.ticks(5);
var yAxis = d3.svg.axis().scale(y)
.orient("left")
.ticks(5);
//assigns coordinates for each piece of data
var valueline = d3.svg.line()
.interpolate("interpolation")
.x(function(d) { return x(d.date); })
.y(function(d) { return y(d.close); });
//second line data
var valueline2 = d3.svg.line()
.x(function(d) { return x(d.date); })
.y(function(d) { return y(d.open); });
//create area for 'area' below line
var area = d3.svg.area()
.x(function(d) { return x(d.date); })
.y0(height)
.y1(function(d) { return y(d.close); });
//creates area to draw graph
var svg = d3.select("body")
.append("svg")
.attr("width", width + margin.left + margin.right)
.attr("height", height + margin.top + margin.bottom)
//groups content
.append("g")
.attr("transform", "translate(" + margin.left + "," + margin.top + ")");
function make_x_axis() {
return d3.svg.axis()
.scale(x)
.orient("bottom")
.ticks(5)
}
function make_y_axis() {
return d3.svg.axis()
.scale(y)
.orient("left")
.ticks(30)
}
// csv callback function
d3.csv("myData3.csv", function(data) {
data.forEach(function(d) {
d.date = parseDate(d.date);
d.close = +d.close;
d.open = +d.open;
});
//INPUT DOMAINS
//.extent() returns min and max values of argument
x.domain(d3.extent(data, function(d) { return d.date; }));
//returns max of whichever set of data is bigger
y.domain([0, d3.max(data, function(d) { return Math.max(d.close, d.open); })]);
d3.select("#button1").on("click", function(){
var path = svg.append("path") // Add the valueline path.
.attr("class", "line")
.attr("d", valueline(data))
.attr("stroke", "steelblue")
.attr("stroke-width", "5")
.attr("fill", "none");
var totalLength = path.node().getTotalLength();
path
.attr("stroke-dasharray", totalLength + "30" * 30)
.attr("stroke-dashoffset", totalLength)
.transition()
.duration(2000)
.ease("linear")
.attr("stroke-dashoffset", 0);
})
d3.select("#button2").on("click", function(){
var path2 = svg.append("path") // Add the valueline path.
.attr("class", "line2")
.attr("d", valueline2(data))
.attr("stroke", "steelblue")
.attr("stroke-width", "5")
.attr("fill", "none");
var totalLength = path2.node().getTotalLength();
path2
.attr("stroke-dasharray", totalLength + "30" * 30)
.attr("stroke-dashoffset", totalLength)
.transition()
.duration(2000)
.ease("linear")
.attr("stroke-dashoffset", 0)
})
svg.append("g") // Add the X Axis
.attr("class", "x axis")
//moves x axis to bottom of graph
.attr("transform", "translate(0," + height + ")")
.call(xAxis);
//text label for x-axis
svg.append("text") // text label for the x axis
.attr("transform", "translate(" + (width / 2) + " ," + (height + margin.bottom - 5 ) + ")")
.style("text-anchor", "middle")
.text("Date");
svg.append("g") // Add the Y Axis
.attr("class", "y axis")
.call(yAxis);
//text label for y-axis
svg.append("text")
.attr("transform", "rotate(-90)")
.attr("y", 0 - margin.left)
.attr("x",0 - (height / 2))
//adds extra left padding as original y pos = 0
.attr("dy", "1em")
.style("text-anchor", "middle")
.text("Value");
//adding a title to the graph
svg.append("text")
.attr("x", (width / 2))
.attr("y", 0 - (margin.top / 2))
.attr("text-anchor", "middle")
.style("font-size", "16px")
.style("text-decoration", "underline")
.text("Graph");
//draw x axis grid
svg.append("g")
.attr("class", "grid")
.attr("transform", "translate(0," + height + ")")
.call(make_x_axis()
.tickSize(-height, 0, 0)
.tickFormat("")
)
//draw y axis grid
svg.append("g")
.attr("class", "grid")
.call(make_y_axis()
.tickSize(-width, 0, 0)
.tickFormat("")
)
});<!--d3.csv close-->
Thanks in advance!
The easiest way to add a tooltip is to append an svg:title element to the elements you want to have a tooltip for. It will be displayed by the browser automatically when you hover over the element. It works for all kinds of elements as well.
So your code would need to look something like
var path = svg.append("path") // Add the valueline path.
.attr("class", "line")
.attr("d", valueline(data))
.attr("stroke", "steelblue")
.attr("stroke-width", "5")
.attr("fill", "none")
.append("title").text("whatever");
If you need more sophisticated functionality, you could try for example tipsy, which works in a similar way.