D3 js update plot just adds new points on top - javascript

I have a graph that has data updating every second. The limits do not change and all I want to do is clear the graph and put the new points onto it. But currently this just adds all of the points on top of the last ones.
main.append('g')
.attr('transform', 'translate(0,0)')
.attr('class', 'main axis date')
.call(yAxis);
g = main.append("svg:g");
function update(data){
g.selectAll("scatter-dots")
.data(data)
.enter().append("svg:circle") // create a new circle for each value
.attr("cy", function (d) { return y(d); } ) // translate y value to a pixel
.attr("cx", function (d,i) { return x(xdata[i]); } ) // translate x value
.attr("r", 4); // radius of circle
}

You should just need to add an exit() call to tell d3 to remove any points from the graph that are no longer in the dataset. Generally you will also want to use an enter (for new elements), update (for existing elements), and exit (for removed elements) strategy when working with d3. The pattern usually looks like this:
function update(data){
var points = g.selectAll("scatter-dots").data(data);
points.enter().append("svg:circle"); // create a new circle for each value
points
.attr("cy", function (d) { return y(d); } ) // translate y value to a pixel
.attr("cx", function (d,i) { return x(xdata[i]); } ) // translate x value
.attr("r", 4); // radius of circle
points.exit().remove();
}

Related

D3 - How to update force simulation when data values change

I'm stuck on a small problem regarding force simulation in D3.
I have data representing poverty rates for each country, from 1998 to 2008. It's a bubble chart that's split into three clusters, representing poor countries, not-poor countries, and countries with no information.
When the app is initially loaded, it's loaded with the 1998 data. However, I have some buttons at the top, that, when clicked, will change the year, and subsequently the bubbles should rearrange themselves. All I've been able to do, is when the button is clicked, I change a variable year. However, there are functions and variables that use year throughout the code. When year changes, I want to recalculate all the node properties and force parameters that are depending on year
Here's my code. I've included all of it in case you want to try it out. The data file is at the end of this post.
async function init() {
// Set up the canvas
var height = 1000, width = 2000;
var svg = d3.select("#panel1").append("svg")
.attr("height", height)
.attr("width", width)
.attr("class", "bubblePanel");
var canvas = svg.append("g")
.attr("transform", "translate(0,0)");
// Choose what year to look at, based on button clicks.
var year = "X1998"
d3.select("#b1998").on("click", function() {
year = "X1998"
console.log(year)
// NOTIFY SIMULATION OF CHANGE //
})
d3.select("#b1999").on("click", function() {
year = "X1999"
console.log(year)
// NOTIFY SIMULATION OF CHANGE //
})
d3.select("#b2000").on("click", function() {
year = "X2000"
console.log(year)
// NOTIFY SIMULATION OF CHANGE //
})
// Implement the physics of the elements. Three forces act according to the poverty level (poor, not poor, and no info)
var simulation = d3.forceSimulation()
.force("x", d3.forceX(function(d) {
if (parseFloat(d[year]) >= 10) {
return 1700
} else if (parseFloat(d[year]) === 0) {
return 1000
} else {
return 300
}
}).strength(0.05))
.force("y", d3.forceY(300).strength(0.05))
.force("collide", d3.forceCollide(function(d) {
return radiusScale(d[year])
}));
// Function to pick colour of circles according to region
function pickColor(d) {
if (d === "East Asia & Pacific") {
return "red"
} else if (d === "Europe & Central Asia") {
return "orange"
} else if (d === "Latin America & Caribbean") {
return "yellow"
} else if (d === "Middle East & North Africa") {
return "green"
} else if (d === "North America") {
return "blue"
} else if (d === "South Asia") {
return "indigo"
} else {
return "violet"
}
}
// Set the scales for bubble radius, and text size.
var radiusScale = d3.scaleSqrt().domain([0, 50]).range([20,80]);
var labelScale = d3.scaleSqrt().domain([0,50]).range([10,40]);
// Read the data
await d3.csv("wd3.csv").then(function(data) {
// Assign each data point to a circle that is colored according to region and has radius according to its poverty level
var bubbles = svg.selectAll("circle")
.data(data)
.enter().append("circle")
.attr("cx", 100)
.attr("cy", 100)
.attr("fill", function(d) {
return pickColor(d.Region)
})
.attr("r", function(d) {
return radiusScale(d[year])
});
// Assign each ddata point to a text element that shows the counry code of the data point. The text is scaled according to the poverty level
var labels = svg.selectAll("text")
.data(data)
.enter().append("text")
.attr("x", 100)
.attr("y", 100)
.attr("dominant-baseline", "central")
.text(function(d) { return d.XCountryCode })
.style("stroke", "black")
.style("text-anchor", "middle")
.style("font-size", function(d) { return labelScale(d[year]); });
// Code to handle the physics of the bubble and the text
simulation.nodes(data)
.on("tick", ticked)
function ticked() {
bubbles.attr("transform", function(d) {
var k = "translate(" + d.x + "," + d.y + ")";
return k;
})
labels.attr("transform", function(d) {
var k = "translate(" + d.x + "," + d.y + ")";
return k;
})
}
});
}
When year changes, the data values will change for each country. I want the following parts of my code to be updated.
The x forces on the nodes: Countries can go from poor in one year to not-poor in another year, so their cluster will change
The radius of the circles: The radius represents poverty level. These change from year to year, so the size of the circles will change when a button is clicked
The coordinates of the country labels: These labels are attached to the data as well. So when the x forces on the circles causes the circles to move, the labels should move as well.
I'd greatly appreciate the help.
The data file can be found here. I accidentally named it povertyCSV, but in the code, it's referenced as "wd3.csv"
If I understand the question correctly:
Re-initializing Forces
The functions provided to set parameters of d3 forces such as forceX or forceCollision are executed once per node at initialization of the simulation (when nodes are originally assigned to the layout). This saves a lot of time once the simulation starts: we aren't recalculating force parameters every tick.
However, if you have an existing force layout and want to modify forceX with a new x value or new strength, or forceCollision with a new radius, for example, we can re-initialize the force to perform the recalculation:
// assign a force to the force diagram:
simulation.force("someForce", d3.forceSomeForce().someProperty(function(d) { ... }) )
// re-initialize the force
simulation.force("someForce").initialize(nodes);
This means if we have a force such as:
simulation.force("x",d3.forceX().x(function(d) { return fn(d["year"]); }))
And we update the variable year, all we need to do is:
year = "newValue";
simulation.force("x").initialize(nodes);
Positioning
If the forces are re-initialized (or re-assigned), there is no need to touch the tick function: it'll update the nodes as needed. Labels and circles will continue to be updated correctly.
Also, non-positional things such as color need to be updated in the event handler that also re-initializes the forces. Other than radius, most things should either be updated via the force or via modifying the elements directly, not both.
Radius is a special case:
With d3.forceCollide, radius affects positioning
Radius, however, does not need to be updated every tick.
Therefore, when updating the radius, we need to update the collision force and modify the r attribute of each circle.
If looking for a smooth transition of radius that is reflected graphically and in the collision force, this should be a separate question.
Implementation
I've borrowed from your code to make a fairly generic example. The below code contains the following event listener for some buttons where each button's datum is a year:
buttons.on("click", function(d) {
// d is the year:
year = d;
// reheat the simulation:
simulation
.alpha(0.5)
.alphaTarget(0.3)
.restart();
// (re)initialize the forces
simulation.force("x").initialize(data);
simulation.force("collide").initialize(data);
// update altered visual properties:
bubbles.attr("r", function(d) {
return radiusScale(d[year]);
}).attr("fill", function(d) {
return colorScale(d[year]);
})
})
The following snippet uses arbitrary data and due to its size may not allow for nodes to re-organize perfectly every time. For simplicity, position, color, and radius are all based off the same variable. Ultimately, it should address the key part of the question: When year changes, I want to update everything that uses year to set node and force properties.
var data = [
{year1:2,year2:1,year3:3,label:"a"},
{year1:3,year2:4,year3:5,label:"b"},
{year1:5,year2:9,year3:7,label:"c"},
{year1:8,year2:16,year3:11,label:"d"},
{year1:13,year2:25,year3:13,label:"e"},
{year1:21,year2:36,year3:17,label:"f"},
{year1:34,year2:1,year3:19,label:"g"},
{year1:2,year2:4,year3:23,label:"h"},
{year1:3,year2:9,year3:29,label:"i"},
{year1:5,year2:16,year3:31,label:"j"},
{year1:8,year2:25,year3:37,label:"k"},
{year1:13,year2:36,year3:3,label:"l"},
{year1:21,year2:1,year3:5,label:"m"}
];
// Create some buttons:
var buttons = d3.select("body").selectAll("button")
.data(["year1","year2","year3"])
.enter()
.append("button")
.text(function(d) { return d; })
// Go about setting the force layout:
var svg = d3.select("body")
.append("svg")
.attr("width", 500)
.attr("height", 300);
var radiusScale = d3.scaleSqrt()
.domain([0, 40])
.range([5,30]);
var colorScale = d3.scaleLinear()
.domain([0,10,37])
.range(["#c7e9b4","#41b6c4","#253494"]);
var year = "year1";
var simulation = d3.forceSimulation()
.force("x", d3.forceX(function(d) {
if (parseFloat(d[year]) >= 15) {
return 100
} else if (parseFloat(d[year]) > 5) {
return 250
} else {
return 400
}
}).strength(0.05))
.force("y", d3.forceY(150).strength(0.05))
.force("collide", d3.forceCollide()
.radius(function(d) {
return radiusScale(d[year])
}));
var bubbles = svg.selectAll("circle")
.data(data)
.enter().append("circle")
.attr("r", function(d) {
return radiusScale(d[year])
})
.attr("fill", function(d) {
return colorScale(d[year]);
});
var labels = svg.selectAll("text")
.data(data)
.enter()
.append("text")
.text(function(d) {
return d.label;
})
.style("text-anchor","middle");
simulation.nodes(data)
.on("tick", ticked)
function ticked() {
bubbles.attr("cx", function(d) {
return d.x;
}).attr("cy", function(d) {
return d.y;
})
labels.attr("x", function(d) {
return d.x;
})
.attr("y", function(d) {
return d.y +5;
})
}
buttons.on("click", function(d) {
// d is the year:
year = d;
simulation
.alpha(0.5)
.alphaTarget(0.3)
.restart();
simulation.force("x").initialize(data);
simulation.force("collide").initialize(data);
bubbles.attr("r", function(d) {
return radiusScale(d[year]);
}).attr("fill", function(d) {
return colorScale(d[year]);
})
})
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/5.7.0/d3.min.js"></script>

Updating chart data, but not all bars redrawing

I'm working on a bar chart that updates its data based on the mouseover of another element. When the chart updates, if there are less bars in the new chart, the chart permanently has fewer bars and changing the data back does not add them back in. I've added a gif to show this - when it gets down to 3 bars, they never come back.
Here's my code:
var scatter_versus_dataset; // the main set
var scatter_versus_dataset_filtered;
// set versus y scale
scatter_versus_y = d3.scaleBand().range([0, SCATTER_VERSUS_HEIGHT])
// set versus x scale
scatter_versus_x_fatal = d3.scaleLinear().range([0, SCATTER_VERSUS_WIDTH / 3]);
scatter_versus_x_nonfatal = d3.scaleLinear().range([-1 * SCATTER_VERSUS_WIDTH / 3, 0 ])
// set the versus colors
scatter_versus_z = d3.scaleOrdinal().range(STACK_COLOURS);
...
function updateScatterVersus(code){
// filter the set
scatter_versus_dataset_filtered = scatter_versus_dataset.filter(function (d) { return (d.majorOccCodeGroup == code) })
scatter_versus_y.domain(scatter_versus_dataset_filtered.map(function (d) { return d.occupation; })).padding(BAR_PADDING);
scatter_versus_x_fatal.domain([0, d3.max(scatter_versus_dataset_filtered, function (d) { return d.f_total_rate; })]).nice();
scatter_versus_x_nonfatal.domain([d3.min(scatter_versus_dataset_filtered, function (d) { return +-1 * d.nf_total_rate; }), 0]).nice();
var bars = d3.selectAll("#scatter_versus_fatal_rect")
.data(scatter_versus_dataset_filtered)
bars.exit()
.remove()
bars.transition()
.duration(600)
.attr("y", function (d) {
return scatter_versus_y(d.occupation);
})
.attr("x", function (d) {
return scatter_versus_x_fatal(0) + SCATTER_VERSUS_GAP_HALF;
})
.attr("width", function (d) {
return scatter_versus_x_fatal(d.f_total_rate);
})
.attr("height", scatter_versus_y.bandwidth())
bars.enter()
.append("rect")
.attr('id', 'scatter_versus_fatal_rect')
.classed("bar", true)
.attr("y", function (d) {
return scatter_versus_y(d.occupation);
})
.attr("x", function (d) {
return scatter_versus_x_fatal(0) + SCATTER_VERSUS_GAP_HALF;
})
.attr("width", function (d) {
return scatter_versus_x_fatal(d.f_total_rate);
})
.attr("height", scatter_versus_y.bandwidth())
}
The process for redrawing the other side of the chart is exactly the same. The problem is still there if i only draw one of the sides.
The data is just from a csv, and I don't think it's the problem - the filtered set has the right number of entries and it's fine in other charts. It's probably something to do with the removal and redrawing but I can't find many examples of this. Or perhaps a key? I can upload some data if needed but it's a pretty big CSV.
id in HTML is unique, only 1 tag should have it.
Select the div for the bars, then selectAll tags with class is bar and bind data.
Remove the id you add to the rects.
var bars = d3.select("#scatter_versus_fatal_rect")
.selectAll(".bar")
.data(scatter_versus_dataset_filtered);
bars.enter()
.append("rect")
// .attr('id', 'scatter_versus_fatal_rect')
.classed("bar", true)
......

D3 choropleth map with legend

I have a choropleth map of the united states showing total population. I would like to add a legend to the map showing the quantile range values.I’ve seen other similar questions about this topic but can’t seem to get it to work for my specific case. I know I need to include the color range or color domain but just not sure if this is the correct way. As of right now just one feature shows up in the legend, could it be that all the legend features are stacked on top of each other. How can I know for sure and how can I fix this.
//Define default colorbrewer scheme
var colorSchemeSelect = "Greens";
var colorScheme = colorbrewer[colorSchemeSelect];
//define default number of quantiles
var quantiles = 5;
//Define quantile scale to sort data values into buckets of color
var color = d3.scale.quantile()
.range(colorScheme[quantiles]);
d3.csv(data, function (data) {
color.domain([
d3.min(data, function (d) {
return d.value;
}),
d3.max(data, function (d
return d.value
})
]);
//legend
var legend = svg.selectAll('rect')
.data(color.domain().reverse())
.enter()
.append('rect')
.attr("x", width - 780)
.attr("y", function(d, i) {
return i * 20;
})
.attr("width", 10)
.attr("height", 10)
.style("fill", color);
The legend code that you're using would work perfectly well if you had an ordinal scale, where the domain is made up of discrete values that correlate to the range of colours on a one-to-one basis. But you're using a quantile scale, and so need a different approach.
For a d3 quantile scale, the domain is the list of all possible input values, and the range is a list of discrete output values. The domain list is sorted in ascending order and then divided into equal-sized groups, which are assigned to each output value from the range. The number of groups is determined by the number of output values.
With that in mind, in order to get one legend entry for each colour, you're going to need to use your colour scale's range, not the domain, as the data for your legend. Then you can use the quantileScale.invertExtent() method to find the minimum and maximum input values that are getting drawn with that colour.
Sample code, making each legend entry a <g> containing both the coloured rectangle and a text label showing the corresponding values.
var legend = svg.selectAll('g.legendEntry')
.data(color.range().reverse())
.enter()
.append('g').attr('class', 'legendEntry');
legend
.append('rect')
.attr("x", width - 780)
.attr("y", function(d, i) {
return i * 20;
})
.attr("width", 10)
.attr("height", 10)
.style("stroke", "black")
.style("stroke-width", 1)
.style("fill", function(d){return d;});
//the data objects are the fill colors
legend
.append('text')
.attr("x", width - 765) //leave 5 pixel space after the <rect>
.attr("y", function(d, i) {
return i * 20;
})
.attr("dy", "0.8em") //place text one line *below* the x,y point
.text(function(d,i) {
var extent = color.invertExtent(d);
//extent will be a two-element array, format it however you want:
var format = d3.format("0.2f");
return format(+extent[0]) + " - " + format(+extent[1]);
});

D3 adding element to zoomed map

I have a map where circles (origin of people) appear when clicking on a legend.
Additionally, it is possible to zoom in, and then, circles (and country path) are transformed (using d3.behavior.zoom).
Though, if I first zoom in, and then click on the legend, circles do not appear at the right places. How can I solve this problem and append them at the right coordinates (within the zoomed map).
Any ideas? I'm sure the solution is not that difficult, but I'm stucked.
See (http://wahrendorf.de/circlemapping/world_question.html) for an example.
Thanks,
Morten
You need to take into account d3.event.translate and d3.event.scale when you draw the circles. The easiest way to do this is to factor out your zoom function so that it may be called by the circle drawing function.
var translate = [0,0];
var scale = 1;
var zoom_function = function() {
canvas.selectAll("path")
.attr("transform","translate("+translate.join(",")+")scale("+scale+")");
canvas.selectAll("circle.origin")
.attr("transform","translate("+translate.join(",")+")scale("+scale+")")
.attr("r", function(d) { return radius/scale; });
};
var zoom = d3.behavior.zoom().scaleExtent([1,6])
.on("zoom",function() {
translate = d3.event.translate;
scale = d3.event.scale;
zoom_function();
});
// ... The rest of the code ...
canvas.append("text")
.text("show circles")
.attr("x", 30 ) .attr("y", 480 )
.attr("dy", ".35em")
.on("click", function(d) {
/// load data with long/lat of circles
d3.csv("./World_files/places_q.csv", function(error, origin) {
canvas.selectAll("circle.origin").remove();
canvas.selectAll("circle.origin")
.data(origin)
.enter()
.append("circle")
.attr("cx", function(d) {return projection([d.originlong, d.originlat])[0];})
.attr("cy", function(d) {return projection([d.originlong, d.originlat])[1];})
.attr("r", 2)
.style("fill", "red")
.style("opacity", 0.5)
.attr("class", "origin");
// Call the zoom function here to fix the placement of the circles.
zoom_function();
});
});
You will need to track the last known d3.event.translate and d3.event.scale values since they will be undefined when you are drawing the circles.

D3 line graph not filling entire svg width

As the title states, I have created a D3 line/area graph, and I am finding it difficult to get the graph's width to remain constant, depending on the amount of data I have given it to render, it scales the width of the graph accordingly, but I am unsure of how I can get it to remain at a constant width, regardless of the amount of data given, which is what I would like to achieve.
I imagine it has something to do with the scaling of the x and y coordinates, but I am stuck at the moment and can't seem to figure out why it is doing this.
Here is the code I have thus far,
//dimensions and margins
var width = 625,
height = 350,
margin = 5,
// get the svg and set it's width/height
svg = d3.select("#main")
.attr("width", width)
.attr("height", height);
//initialize the graph
init([
[12345,42345,32345,22345,72345,62345,32345,92345,52345,22345],
[1234,4234,3234,2234,7234,6234,3234,9234,5234,2234]
]);
$("button").live('click', function(){
var id = $(this).attr("id");
if(id == "one"){
updateGraph([
[52345,32345,12345,22345,62345,72345,92345,32345,22345,22345,52345,32345,12345,22345,62345,72345,92345,32345,22345,22345,52345,32345,12345,22345,62345,72345,92345,32345,22345,22345],
[4234,12345,2234,32345,6234,7234,9234,3234,2234,2234,4234,1234,2234,3234,6234,7234,9234,3234,2234,2234,4234,1234,2234,3234,6234,7234,9234,3234,2234,2234]
]);
}else if(id == "two"){
updateGraph([
[12345,42345,32345,22345,72345,62345,32345,92345,52345,22345,12345,42345,32345,22345,72345,62345,32345,92345,52345,22345,12345,42345,32345,22345,72345],
[1234,2345,3234,2234,7234,6234,3234,9234,5234,2234,1234,4234,3234,2234,7234,6234,3234,9234,5234,2234,1234,4234,3234,2234,7234]
]);
}
});
function init(data){
var x = d3.scale.linear()
.domain([0,data[0].length])
.range([margin, width-margin]),
y = d3.scale.linear()
.domain([0,d3.max(data[0])])
.range([height-margin, margin]),
/* line path generator */
line = d3.svg.line().interpolate('monotone')
.x(function(d,i) { return x(i); })
.y(function(d) { return y(d); }),
/* area path generator */
area = d3.svg.area().interpolate('monotone')
.x(line.x())
.y1(line.y())
.y0(y(0)),
groups = svg.selectAll("g")
.data(data)
.enter()
.append("g");
svg.select("g")
.selectAll("circle")
.data(data[0])
.enter()
.append("circle")
.attr("class", "dot")
.attr("cx", line.x())
.attr("cy", line.y())
.attr("r", 4);
/* add the areas */
groups.append("path")
.attr("class", "area")
.attr("d",area)
.style("fill", function(d,i) { return (i == 0 ? "steelblue" : "red" ); });
/* add the lines */
groups.append("path")
.attr("class", "line")
.attr("d", line);
}
function updateGraph(data){
var x = d3.scale.linear()
.domain([0,data[0].length])
.range([margin, width-margin]),
y = d3.scale.linear()
.domain([0,d3.max(data[0])])
.range([height-margin, margin]),
/* line path generator */
line = d3.svg.line().interpolate('monotone')
.x(function(d,i) { return x(i); })
.y(function(d) { return y(d); }),
/* area path generator */
area = d3.svg.area().interpolate('monotone')
.x(line.x())
.y1(line.y())
.y0(y(0));
groups = svg.selectAll("g")
.data(data),
circles = svg.select("g")
.selectAll("circle");
circles.data(data[0])
.exit().remove();
circles.data(data[0])
.enter().append("circle")
.attr("class", "dot")
.attr("cx", line.x())
.attr("cy", line.y())
.attr("r", 4);
/* animate circles */
circles.data(data[0])
.transition()
.duration(1000)
.attr("cx", line.x())
.attr("cy", line.y());
/* animate the lines */
groups.select('.line')
.transition()
.duration(1000)
.attr("d",line);
/* animate the areas */
groups.select('.area')
.transition()
.duration(1000)
.attr("d",area);
}
​
As well as a fiddle http://jsfiddle.net/JL33M/
Thank you!
The width of the graph depends on the range() you give it. range([0,100]) will always "stretch" the domain() values to take up 100 units.
That's what your code is currently doing:
var x = d3.scale.linear()
.domain([0,data[0].length])
.range([margin, width-margin]);// <-- always a fixed width
You want the width to depend on the number of data entries. Say you've decided you want each data point to take up 5 units, then range() needs to depend on the size of the dataset:
var x = d3.scale.linear()
.domain([0,data[0].length])
.range([margin, 5 * data[0].length]);// <-- 5 units per data point
Of course, under these conditions, your graph width grows with the dataset; if you give it a really long data array of, say, 500 points, the graph would be 2500 units wide and likely run off screen. But if your data is such that you know the maximum length of it, then you'll be fine.
On an unrelated note, I think your code could use a refactoring to be less repetitive. You should be able to achieve what you're doing with a single update() function, without the need for the init() function.
This tutorial by mbostock describe the "general update pattern" I'm referring to. Parts II and III then go on to explaining how to work transitions into this pattern.

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