Coordinates of each center's arc in a pie chart - d3.js

In order to draw a baton that its starting point takes coordinates of arc's center in a Pie Chart d3 js, How can determinate coordinates of each arcs's center ?
I tried this code but only the first baton was in the right position.
var lines = arcs.selectAll("line")
.data(data)
.enter()
.append("line")
.attr("x1", function(d, i) { return r*Math.cos( parseFloat(d)/r);})
.attr("y1", function(d) { return r*Math.sin( parseFloat(d)/r) ;})
.attr("x2", function(d) { return r*Math.cos( parseFloat(d)/r) + parseFloat(d) ;})
.attr("y2", function(d) { return r*Math.sin( parseFloat(d)/r) + parseFloat(d) ;})
.attr("class", "line")
.style("stroke", function (d) {return color(d.data) ; })
.style("stroke-width", "3px");
Please i need your help.

As pointed out in the comments, the arc.centroid() function provides this functionality:
var pie = d3.layout.pie().value(function(d){ return d.value; });
var arc = d3.svg.arc().innerRadius(0).outerRadius(r);
var centers = pie(data).map(arc.centroid);
Or with a D3 selection:
var centers = [];
arcs.each(function(d) {
centers.push(arc.centroid(d));
});
Complete demo here.

Related

How to define which points for interpolation in radial line

Very much D3 newbie here, feeling my way around adapting an existing radar chart built in D3 v3.5.9
I'm having an issue in interpolating between points when there are zero values between them.
Example:
radar when all data points are present, looks fine
radar when there are zero values
The behaviour I want is for the interpolation to go around the circle, rather than just closing the sections bounded by the non-zero values.
green lines show desired behaviour whenever a zero is encountered
I have used the 'defined' function to find zero values in the source data, but I need to add something else to instruct D3 to draw the connecting lines between the desired points. Something with the index value for d, probably?
Or perhaps 'defined' is not the right function in this case?
var radarLine = d3.svg.line
.radial()
.defined(function (d) {
return d.value !== 0;
})
.interpolate("linear-closed")
.radius(function (d) {
return rScale(d.value);
})
.angle(function (d, i) {
return i * angleSlice;
});
if (cfg.roundStrokes) {
radarLine.interpolate("cardinal-closed");
}
//Create a wrapper for the blobs
var blobWrapper = g
.selectAll(".radarWrapper")
.data(data)
.enter()
.append("g")
.attr("class", "radarWrapper");
//Append the backgrounds
blobWrapper
.append("path")
//.attr("class", "radarArea")
.attr("class", function (d) {
return "radarArea" + " " + d[0].radar_area.replace(/\s+/g, "");
})
.attr("d", function (d, i) {
return radarLine(d);
})
.style("fill", function (d, i) {
return cfg.color(i);
})
.style("fill-opacity", 0);
//Create the outlines
blobWrapper
.append("path")
.attr("class", "radarStroke")
.attr("d", function (d, i) {
return radarLine(d);
})
.style("stroke-width", cfg.strokeWidth + "px")
.style("stroke", function (d, i) {
return cfg.color(i);
})
.style("fill", "none");
Any help would be greatly appreciated!

I have to append text in my d3.js code but it's not displaying text

script type="text/javascript">
d3.csv("mydata.csv", function(data){
var svgcontainer = d3.select("body").append("svg")
.attr("width",500)
.attr("height",500)
svgcontainer.selectAll("rect")
.data(data)
.enter()
.append("rect")
.attr("width" ,function (d) { return d.age * 10;})
.attr("height" ,45)
.attr("y",function(d,i) { return i*50; })
.attr("fill","blue")
svgcontainer.selectAll("text")
.data(data)
.enter()
.append("text")
.attr("fill","white")
//.attr("y",function(d,i) { return i*50 ; })
.text( function (d) { return d.name; })
})
I have to append text in my d3.js code but it's not displaying text.I am new to d3.js so please any one help me. Here is my code-
From the first observation i will get to know the issue related with the text element position in svg. In SVG Coordinate positions are very important to achieve the graphical representation. In above code snippet x and y positions are missing. sample code below:-
svgcontainer.append("text")
.attr("x", function(d) { return x(d.value) - 3; })
.attr("y", barHeight / 2)
.attr("dy", ".35em")
.text(function(d) { return d.value; });
Example

Warbling circle using d3

I wanted to draw a pulsating warbling circle on a geomap using d3, using this example for guidance. However—and I know this is a very basic question, so apologies—I can't seem to get the selector to fire right. Here is the relevant code:
layer2
.attr("id", "locations")
.selectAll(".state")
.data(columbia.features)
.enter().append("circle")
.attr("class", "location")
.attr("r", "4px")
.attr("cx", function(d) { return proj(d['geometry']['coordinates'])[0]; })
.attr("cy", function(d) { return proj(d['geometry']['coordinates'])[1]; })
.attr("d", path)
.each(pulse);
function pulse() {
var circle = svg.select(".location");
console.log(circle);
(function repeat() {
circle = circle.transition()
.duration(2000)
.attr("stroke-width", 20)
.attr("r", 10)
.transition()
.duration(2000)
.attr('stroke-width', 0.5)
.attr("r", 200)
.ease('sine')
.each("end", repeat);
})();
}
Right now I have:
var circle = svg.select(".location");
What should I have instead of .location?
Here is the full file.
Edit: got it; I need selectAll, notselect.

D3 vertical line graph

I have a line (& area) graph which works ok, when horizontal. But I really need it to be vertical, to stand up. I have tried all kinds of changes to the existing code. Mostly with some strange results.
Here’s the code (modified it a bit). Is there a way to change it to make the graph vertical?:
var x = d3.scale.linear().domain([1, itemCount]).range([0, width]);
var y = d3.scale.linear().domain([0, maxValue]).rangeRound([height, 0]);
// Set up linar x and y axis.
var xAxis = d3.svg.axis().scale(x).ticks(10);
var yAxis = d3.svg.axis().scale(y).ticks(2).orient("left");
// Line graph.
line = d3.svg.line()
.interpolate("basis")
.x(function (d) {
return x(d.x);
})
.y(function (d) {
return y(d.y);
});
// Create SVG element.
var svg = d3.select("body")
.append("svg")
.attr("width", width)
.attr("height", height);
// X-Axis, to bottom.
svg.append("svg:g")
.attr("class", "axis")
.attr("transform", "translate(1," + height + ")")
.call(xAxis);
//Y-Axis
svg.append("svg:g")
.attr("class", "axis")
.attr("transform", "translate(40, 1)")
.call(yAxis);
// Horizontal axis guide lines.
svg.selectAll("line.y")
.data(y.ticks(5))
.enter()
.append("line")
.attr("x1", 0)
.attr("x2", width)
.attr("y1", y)
.attr("y2", y)
.style("stroke", "#000000")
.style("stroke-opacity", 0.1);
// Vertical axis guide lines.
svg.selectAll("line.x")
.data(y.ticks(5))
.enter()
.append("line")
.attr("x1", x)
.attr("x2", x)
.attr("y1", 0)
.attr("y2", this.heightInside - pushDown)
.style("stroke", "#000000")
.style("stroke-opacity", 0.1);
// Set up domains. Nice ensures the domains ends on nice round values.
x.domain([dataValues[0].x, dataValues[dataValues.length - 1].x]).nice();
y.domain([d3.min(dataValues, function (d) { return (d.y); }),
d3.max(dataValues, function (d) { return (d.y); })])
.nice();
// Draw line on graph.
svg.append("svg:path")
.attr("class", "line")
.attr("d", line(dataValues))
.style("stroke", function(d) { return colors[i]; });
// Marks.
svg.selectAll("circle_" + i)
.data(dataValues)
.enter()
.append("circle")
.style("fill", function(d) { return _this.colors[i]; })
.attr("r", 4)
.attr('cx', function (d) { return x(d.x); })
.attr('cy', function (d) { return y(d.y); });

Create a line connecting circles upon mouse hover

I have a scatter plot made in D3 with circles denoting each data point. Here's my code:
viz.selectAll('circle')
.data(data)
.enter()
.append('circle')
.attr("cx", function(d) {return x(d.x)})
.attr("cy", function(d) {return y(d.y)})
.attr("r", 5)
.attr("fill", function(d) {return d.color})
.on('mouseover', function(d){
console.log(d.color)
})
What I would like to do is, when a given circle is hovered on, connect all circles through a line that have the same color. How can I do this? I can get the color logged into the console, but I don't understand how I can connect all points with the same color through a line upon mouse click?
You can assign a class with color code to your circles. Use d3.selectAll to retrieve all of them on mouseover. Then retrieve their coordinates and pass the coordinates to draw d3.svg.line.
svg.selectAll(".dot")
.data(data)
.enter().append("circle")
.attr("class", function(d) {
return 'dot color-' + color(d.species).replace('#','');
})
.attr("r", 3.5)
.attr("cx", function(d) { return x(d.sepalWidth); })
.attr("cy", function(d) { return y(d.sepalLength); })
.attr("dot-color", function(d) { return color(d.species).replace('#',''); })
.style("fill", function(d) { return color(d.species); })
.on("mouseover", function() {
d3.selectAll(".color-" + $(this).attr("dot-color"))
.attr("r", 5.5);
})
.on("mouseout", function() {
d3.selectAll(".color-" + $(this).attr("dot-color"))
.attr("r", 3.5);
});
Here's an example with color hover:
http://vida.io/documents/KinEKRkSPSfStA4Eu
You can also do it without relying on a common class attribute. In the mouseover handler:
d3.selectAll('.dot')
.filter(function (dOther) { return d.color == dOther.color })
.attr('r', 3.5)

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