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D3: Combine two colour scales into one

I currently have two variables that I can map to two different colours on two colours scales s1 and s2. s1 gives me the shade of red corresponding to my a value of my variable X (4 different possible colours). s1 gives me the shade of blue corresponding to my a value of my variable Y (4 different possible colours too).
Now what I would like to get is something that allows me to combine these two to get a unique colour for a combination of the variables. So for a pair (X,Y) I get a colour on the scale. So I get a scale of 16 possible colours.
Here is a legend that illustrate the kind of thing I am looking for:
I have been looking at online examples but cannot figure out how to achieve this.

You could combine two threshold scales fairly easily into a new scale function. The core of the function could look like:
d3.scaleBivariate = function() {
function scaleBivariate(value) {
var r = reds(value[0]);
var b = blues(value[1]);
return "rgb("+r+","+((r+b)/2)+","+b+")";
}
var blues = d3.scaleThreshold()
.range([255,205,155,105,55])
.domain([0,1,2,3,4,5]);
var reds = d3.scaleThreshold()
.range([255,205,155,105,55])
.domain([0,1,2,3,4,5]);
return scaleBivariate;
}
This sets the red and blue channels with the help of two d3 threshold scales. The green is simply set as the average between the two, though you could set that to whatever is desirable, say 0 or the minimum of the two other channels. My red/blue ranges are arbitrary and easily changed as well.
The above could be used as:
d3.scaleBivariate = function() {
function scaleBivariate(value) {
var r = reds(value[0]);
var b = blues(value[1]);
return "rgb("+r+","+((r+b)/2)+","+b+")";
}
var blues = d3.scaleThreshold()
.range([255,205,155,105,55])
.domain([0,1,2,3,4,5]);
var reds = d3.scaleThreshold()
.range([255,205,155,105,55])
.domain([0,1,2,3,4,5]);
return scaleBivariate;
}
// Dummy data:
var data = d3.range(16).map(function(d) {
return {x: d%4, y: Math.floor(d/4) }
})
var svg = d3.select("svg");
var size = 30;
var color = d3.scaleBivariate();
svg.selectAll("rect")
.data(data)
.enter()
.append("rect")
.attr("x", function(d) { return d.x * size })
.attr("y", function(d) { return d.y * size })
.attr("width",size)
.attr("height",size)
.attr("fill",function(d) {
return color([d.x,d.y]);
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/5.0.0/d3.min.js"></script>
<svg></svg>
Of course you might want to add some flexibility by adding methods to modify what datum property sets what colors are associated with what properties, what the thresholds should be, etc. To provide a basic example, the example below has added accessors for setting what property should be mapped to blue and red channels:
d3.scaleBivariate = function() {
function scaleBivariate(value) {
var r = reds(red(value));
var b = blues(blue(value));
return "rgb("+r+","+((r+b)/2)+","+b+")";
}
var blues = d3.scaleThreshold()
.range([255,205,155,105,55])
.domain([0,1,2,3,4,5]);
var reds = d3.scaleThreshold()
.range([255,205,155,105,55])
.domain([0,1,2,3,4,5]);
var red = function(d) { return d[0]; }
var blue = function(d) { return d[1];}
// Accessors:
scaleBivariate.red = function(_) {
return arguments.length ? (red = _, scaleBivariate): red;
}
scaleBivariate.blue = function(_) {
return arguments.length ? (blue = _, scaleBivariate): blue;
}
return scaleBivariate;
}
var data = d3.range(16).map(function(d) {
return {x: d%4, y: Math.floor(d/4) }
})
var svg = d3.select("svg");
var size = 30;
// set up the color scale:
var color = d3.scaleBivariate()
.red(function(d) { return d.x; })
.blue(function(d) { return d.y; });
svg.selectAll("rect")
.data(data)
.enter()
.append("rect")
.attr("x", function(d) { return d.x * size })
.attr("y", function(d) { return d.y * size })
.attr("width",size)
.attr("height",size)
.attr("fill",color);
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/5.0.0/d3.min.js"></script>
<svg></svg>

Styling in D3 with a loop?

I wonder if it possible to use styling actions on the same element many times? I got this Array called A which stores 3 colours and I want to go through a loop that fills my element link.
var A = ["blue", "red", "green"]
for ( var i = 0; i < A.length; i++){
link.style("stroke", function(d)
{
return A[i];
}
)
};

To style each link a different style based on the index of that element/datum in the selection. As with many things in d3, this does not require a loop. You can access the index of each datum with code like:
selection.attr("property",function(d,i) {
return array[i];
})
For sake of ease, I've used some circles and fill rather than links and stroke, but the method is identical. The snippet below will color links sequentially based on the colors array.
var svg = d3.select("body")
.append("svg")
.attr("width",500)
.attr("height",300);
var data = [[50,50],[100,50],[200,50],[300,100]];
var colors = ["steelblue","orange","pink","red"]
// create some circles:
var circles = svg.selectAll("circle")
.data(data)
.enter()
.append("circle")
.attr("transform",function(d) { return "translate("+d+")"; })
.attr("r",10)
// to style sequentially, you can use the datum's index:
circles.attr("fill",function(d,i) {
return colors[i];
})
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.4.11/d3.min.js"></script>

Dashed line doesn't work

I have a list of radio buttons indicating a country.
I want that when user clicks on a radio button, the right line chart are loaded.
To do so I have 4 csv files with data for each country.
The csv files are like this:
year,death,value
2012,Tuberculosis,NA
2011,Tuberculosis,NA
2010,Tuberculosis,301
2009,Tuberculosis,344
2008,Tuberculosis,333
2007,Tuberculosis,329
2006,Tuberculosis,350
2005,Tuberculosis,NA
2004,Tuberculosis,NA
2003,Tuberculosis,396
2002,Tuberculosis,413
2001,Tuberculosis,415
2000,Tuberculosis,460
1999,Tuberculosis,517
1998,Tuberculosis,558
1997,Tuberculosis,597
1996,Tuberculosis,609
1995,Tuberculosis,647
2012,Tetanus,NA
2011,Tetanus,NA
2010,Tetanus,17
2009,Tetanus,27
2008,Tetanus,18
...
HERE is my code.
I don't know why Plunker create the error "Bad request".
Anyway, this is my result: if the user clicks on Italy, then the browser loads Italy.csv file and creates the chart, if the user clicks on Hungary, then browser loads Hungary.csv file and creates the chart and so on.
The problem is that in my csv files, there are some "holes" on data.
For example, I haven't any data about number of deaths in Italy between 2003 and 2006 so I want to show a dashed line instead of a solid line.
In my chart I'm not able to do that.
In particular, I wrote code to do that but it doesn't work.
Note that the missing data will change according to the countries. For some countries I have all the data and not for other countries.
Also, if the user clicks on the circle (the legend) of the corresponding series disappears, the circle should turn white and the axes change to fit the current data.
This doesn't work and I don't understand why.
As you can see, the console doesn't show any errors.
In this similar example, it works: PLUNKER
I badly explained myself. With "missing data" I mean NA values.
NEW PLUNKER
I understand that the chart of Belgium is right.
I tried to understand why the Denmark chart is that but sorry, I don't understand when you say "Code generate multiples paths for every abailable data and just ONE path for all NA data. Instead it must generate a segments for every gap on data.".
The code is organized in this way:
// some code...
/**************************************************************************
*** GET SELECTED COUNTRY AND DRAW FIRST CHART ****************************
**************************************************************************/
var l_selectedCountry = document.querySelector('input[name="l_country"]:checked').value;
l_createLineChart(l_selectedCountry);
var l_updateradio = function() {
l_selectedCountry = $('input[name=l_country]:checked', '#l_countries').val();
l_createLineChart(l_selectedCountry);
}
$("#l_countries").on("change", l_updateradio);
/**************************************************************************
*** DRAW THE RIGHT CHART BASED ON SELECTED COUNTRY **********************
**************************************************************************/
function l_createLineChart(l_selectedCountry) {
// remove last chart
d3.select("#l_chartcontainer")
.html("");
// adds the svg canvas
var svg = d3.select("#l_chartcontainer")
.append("svg")
.attr("width", l_width + margin.left + margin.right)
.attr("height", l_height + margin.top + margin.bottom)
.append("g")
.attr("transform", "translate(" + margin.left + "," + margin.top + ")");
var l_file = "./data/line_data/" + l_selectedCountry + ".csv";
/**************************************************************************
*** GET RIGHT DATA ********************************************************
**************************************************************************/
d3.csv(l_file, function(l_error, l_data) {
l_data.forEach(function(d) {
d.year = parseDate(d.year);
d.value = +d.value;
});
// code about axis...
/**************************************************************************
*** GET ALL LINE DATA (solid & dashed) ************************************
**************************************************************************/
var l_dataNest = d3.nest()
.key(function(d) {
return d.death;
})
.entries(l_data);
console.log("l_dataNest");
console.log(l_dataNest);
// code about labels...
/**************************************************************************
*** GET DASHED LINE DATA **************************************************
**************************************************************************/
var l_dashedData = l_getDashed(l_dataNest); // dashed line (extreme point) for each disease
console.log("l_dashedData");
console.log(l_dashedData);
// other code...
/**************************************************************************
*** DRAW SOLID LINE *******************************************************
**************************************************************************/
svg.append('g')
.attr('class', 'l_line-container')
.selectAll('.normal-line-paths')
.data(l_dataNest) // set our data
.enter() // enter the data and start appending elements
.append('path')
.call(l_path); // calling our path function for later use when appending lines
/**************************************************************************
*** DRAW DASHED LINE ******************************************************
**************************************************************************/
svg.append('g')
.attr('class', 'dashed-line-container')
.selectAll('.dashed-line-paths')
.data(l_dashedData)
.enter()
.append('path')
.call(l_dashedPath);
// other code...
});
}
// code about event...
function l_path(myPath) {
myPath.style("fill", "none")
.style("stroke", function(d) {
return l_color[d.key];
})
.attr('class', function(d) {
return 'normal-line-paths path-' + d.key.replace(/\s+/g, '');
})
.attr("d", function(d) {
return valueline(d.values);
})
.style("opacity", 0.5)
.on("mouseover", l_onMouseOverLine)
.on("mouseout", l_onMouseOutLine);
}
function l_dashedPath(myPath) {
myPath.style("fill", "none")
.style("stroke", function(d) {
return l_color[d.key];
})
.style("stroke-width", 5)
.attr("stroke-dasharray", '4')
.attr('class', function(d) {
return 'dashed-line-paths path-' + d.key.replace(/\s+/g, '');
})
.attr("d", function(d) {
return valueline(d.values);
})
.style("opacity", 0.5)
.on("mouseover", l_onMouseOverLine)
.on("mouseout", l_onMouseOutLine);
}
/**
* Function to return the data points that will create the dashed lines.
*/
function l_getDashed(data) {
return data.map(function(collection, index) {
var l_startNaN = false;
var l_dashed = {
key: collection.key, // disease
values: [] //array of death, death and year
};
collection.values.forEach(function(dataPoint, index) {
var l_value = dataPoint.value;
var values = collection.values;
if($.isNumeric(l_value) && l_startNaN) {
l_startNaN = false;
l_dashed.values.push(values[index]);
}
else {
if(($.isNumeric(l_value) && l_startNaN) || (!$.isNumeric(l_value) && !l_startNaN)) {
l_startNaN = true;
l_dashed.values.push(values[index-1]);
}
}
})
if((l_dashed.values.length % 2)) {
l_dashed.values.pop();
}
return l_dashed;
});
}
If I comment this piece of code:
// apend a group element which will contain our dashed lines
/*svg.append('g')
.attr('class', 'dashed-line-container')
.selectAll('.dashed-line-paths')
.data(l_dashedData)
.enter()
.append('path')
.call(l_dashedPath);*/
I get:
and if I comment:
// apend a group element which will contain our lines
/*svg.append('g')
.attr('class', 'l_line-container')
.selectAll('.normal-line-paths')
.data(l_dataNest) // set our data
.enter() // enter the data and start appending elements
.append('path')
.call(l_path); */
I get:
So there must be a problem in l_dashedPath(myPath) method.
But if I print d, I get the four ends of the two portions dashed (Tuberculosis): 23, 32, 15, 16 that are correct.
.attr("d", function(d) {
console.log(d);
return valueline(d.values);
})
Also the l_getDashed(data) method seems correct to me.

Inside Plunker you can't have spaces on filename. Rename it 'United Kingdom.csv' to something with underscore (_) or so. "United_Kingdom.csv"
Your function l_getdashed, don't take the next point for every dashed segment. At the end you just get a point, not a segment.
I'ver re-refactory your function:
function l_getDashed(data) {
return data.map(function(collection, index) {
var l_startNaN = false;
var l_dashed = {
key: collection.key,
values: []
};
collection.values.forEach(function(dataPoint, index) {
var l_value = dataPoint.value;
var values = collection.values;
if ($.isNumeric(l_value) && l_startNaN) {
l_startNaN = false;
l_dashed.values.push(values[index]);
} else if ( !$.isNumeric(l_value) !== l_startNaN) {
l_startNaN = true
l_dashed.values.push(values[index-1]);
}
})
if (l_dashed.values.length % 2) { l_dashed.values.pop() }
return l_dashed;
});
}
Here the update working Plunker
DENMARK
Your code has concept errors. Thats why you see 'Denmark' like that.
Graphically:
Code generate multiples paths for every abailable data and just ONE path for all NA data. Instead it must generate a segments for every gap on data.-
BELGIUM
Belguim is a different history. The graph is ok, your data has isolated points (red dots) and can not be dismiss.
You can not draw a dashed-line from 1997-2009 (black arrow) because you'll discarding data.

Updating several d3.js cartograms in the same container

I'm trying to update 4 cartograms in the same div.
First I create 4 original maps, each in its own svg, like this:
function makeMaps(data){
var mapsWrapper = d3.select('#maps');
data.forEach(function(topoJSON,i){
var quantize = d3.scale.quantize()
.domain([0, 1600000])
.range(d3.range(5).map(function(i) { return "q" + i; }));
var layer = Object.keys(topoJSON.objects)[0]
var svg = mapsWrapper.append('svg')
.attr("class","mapa")
.attr({
width: "350px",
height: "350px"
});
var muns = svg.append("g")
.attr("class", "muns")
.attr("id",layer)
.selectAll("path");
var geometry = topoJSON.objects[layer].geometries;
var carto = cartos[i]
var features = carto.features(topoJSON, geometry),
path = d3.geo.path()
.projection(projections[i]);
muns.data(features)
.enter()
.append("path")
.attr("class", function(d) {
return quantize(d.properties['POB1']);
})
.attr("d", path);
});
}
This part works well and creates 4 maps. After this, I want to update the paths in each map with the paths calculated by cartogram.js. The problem is that I can't get to the path data in each of the maps, here's what I'm trying to do:
...some code to calculate cartogram values
var cartograms = d3.selectAll(".mapa").selectAll("g").selectAll("path")
cartograms.forEach(function(region,i){
region.data(carto_features[i])
.select("title")
.text(function (d) {
return d.properties.nom_mun+ ': '+d.properties[year];
});
In cartograms I'm getting a nested selection: an array of paths for each map, which is what I though I needed, but inside the forEach I get the error region.data() is not a function. Each region is an array of paths each of which has a data property. I've tried with several ways of selecting the paths to no avail and I'm a little lost now. Thanks for your help

d3: Adding and removing force.nodes based on slider values

I had some difficulty a while back adding and removing nodes based on user input which was solved by updating the entire set of objects pushed into force.nodes() each time the user selected which they wanted to view from a list of checkboxes.
Updating from a slider however I think requires a more finesse touch - I don't want to update the entire set every time the slider is moved. I want to push and pop nodes in and out of force.nodes().
With my current code the nodes are coming out just fine - they're just not going back in. jsfiddle here - https://jsfiddle.net/hiwilson1/ancmtxux/3/
This is the part causing problems;
function brushed() {
var exists;
//var newd = new Date(2013, 05, 01)
data.forEach(function(d, i) {
//if data point in range (between extent 0 and 1)
if (d.date >= brush.extent()[0] && d.date <= brush.extent()[1]) {
exists = force.nodes().some(function(node, i) {
//check if data point already exists in force.nodes()
return (node.mIndex == d.mIndex)
})
console.log(exists)
if (!exists) {
force.nodes().push(d)
}
}
else {
force.nodes().splice(i, 1)
}
})
d3.select("#nodeCount").text(force.nodes().length)
}
For each data point, I'm checking whether or not the point lies between extent()[0] and [1]. If it does, then check force.nodes() to see if it's currently a member there. If it isn't, then push it into force.nodes().
If the data point doesn't lie between the extents then splice it from force.nodes(). This last bit works just fine.
UPDATE: Fixed. I actually also worked out how to filter links attached to nodes as well. jsfiddle here - https://jsfiddle.net/hiwilson1/7oumeat5/2/. Never try and do this with indexes/hard coded indexes, compare the nodes/links as objects.
Incidentally I'm seeing links over the top of nodes. If there's some way to fix this I'd be happy to hear it.
FURTHER UPDATE: To ensure links behind nodes use .insert("line", ":first-child") in place of .append("line")

There are a few problems with your current code. The fundamental problem is that you're giving data to force.nodes(), which means that the two data structures are actually the same. That is, when you're removing elements from force.nodes(), you're modifying the underlying data as well. Hence you can't add them back -- they're gone.
This is easily fixed by passing a copy of data to force.nodes():
var force = d3.layout.force()
.nodes(JSON.parse(JSON.stringify(data)))
Then you're removing the wrong nodes from force.nodes() -- the index you're using is for data, not force.nodes(). You can compute the index of the data element in force.nodes() and use it like this:
data.forEach(function(d, i) {
var idx = -1;
force.nodes().forEach(function(node, j) {
if(node.mIndex == d.mIndex) {
idx = j;
}
});
//if data point in range (between extent 0 and 1)
if (d.date >= brush.extent()[0] && d.date <= brush.extent()[1]) {
if (idx == -1) {
force.nodes().push(d)
}
}
else if(idx > -1) {
force.nodes().splice(idx, 1)
}
Finally, you need to call force.start() at the end of brushed for the changes to become visible after the layout has settled down.
Complete example here.

Building on the answer from the mighty #Lars Kotthoff, who fixed your technical problem, I will focus on the architecture. Here is an architecture that is simpler and more in keeping with d3 idiom.
The main principles are:
Use Array.prototype.filter() to manage the data
Use standard, data driven patterns.
Drive the visualisation by managing the data and then use the standard, general update pattern to drive the changes into the vis.
Seperate data events and animation events.
Respond to the data changes only when need... do it in the brushed event, not on every tick. The brushed event is a data event and the tick routine is an animation event. It's not optimal to be managing data on animation events on the off chance that it is required.
Make the entry and exit of the nodes a bit smoother.
The benefit of point 1 is that the filtered array is actually an array of reference to the original data elements, so when the extra state is added on the copied array, it is actually added on the original data array. Thus, the previous state is available when it is filtered back in, hence the smooth exit and entry behaviour. Meanwhile, no elements are deleted in the original data when the brush filters down: only the references to them are deleted in the cloned array. I have to admit I had not expected that but it is a nice discovery, even if by accident!
Of course this only works because the array elements are objects.
working example here...
var width = 700,
height = 600,
padding = 20;
var start = new Date(2013, 0, 1),
end = new Date(2013, 11, 31)
var data = []
for (i = 0; i < 100; i++) {
var point = {}
var year = 2013;
var month = Math.floor(Math.random() * 12)
var day = Math.floor(Math.random() * 28)
point.date = new Date(year, month, day)
point.mIndex = i
data.push(point)
}
var force = d3.layout.force()
.size([width - padding, height - 100])
.on("tick", tick)
.start()
var svg = d3.select("body").append("svg")
.attr({
"width": width,
"height": height
})
//build stuff
var x = d3.time.scale()
.domain([start, end])
.range([padding, width - 6 * padding])
.clamp(true)
var xAxis = d3.svg.axis()
.scale(x)
.tickSize(0)
.tickPadding(20)
//.tickFormat(d3.time.format("%x"))
var brush = d3.svg.brush()
.x(x)
.extent([start, end])
.on("brush", brushed1)
//append stuff
var slidercontainer = svg.append("g")
.attr("transform", "translate(100, 500)")
var axis = slidercontainer.append("g")
.call(xAxis)
var slider = slidercontainer.append("g")
.call(brush)
.classed("slider", true)
//manipulate stuff
d3.selectAll(".resize").append("circle")
.attr("cx", 0)
.attr("cy", 0)
.attr("r", 10)
.attr("fill", "Red")
.classed("handle", true)
d3.select(".domain")
.select(function () { return this.parentNode.appendChild(this.cloneNode(true)) })
.classed("halo", true)
function brushed1(e) {
var nodes = includedNodes(data, brush);
nodes.enter().append("circle")
.attr("r", 10)
.attr("fill", "red")
.call(force.drag)
.attr("class", "node")
.attr("cx", function (d) { return d.x })
.attr("cy", function (d) { return d.y })
nodes
.exit()
.remove()
force
.nodes(includedData(data, brush))
.start()
}
function includedData(data, brush) {
return data.filter(function (d, i, a) {
return d.date >= brush.extent()[0] && d.date <= brush.extent()[1]
})
}
function includedNodes(data, brush) {
return svg.selectAll(".node")
.data(includedData(data, brush), function (d, i) {
return d.mIndex
})
}
function tick() {
includedNodes(data, brush)
.attr("cx", function (d) { return d.x })
.attr("cy", function (d) { return d.y })
}
brushed1()
.domain {
fill: none;
stroke: #000;
stroke-opacity: .3;
stroke-width: 10px;
stroke-linecap: round;
}
.halo {
fill: none;
stroke: #ddd;
stroke-width: 8px;
stroke-linecap: round;
}
.tick {
font-size: 10px;
}
.selecting circle {
fill-opacity: .2;
}
.selecting circle.selected {
stroke: #f00;
}
.handle {
fill: #fff;
stroke: #000;
stroke-opacity: .5;
stroke-width: 1.25px;
cursor: crosshair;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.4.11/d3.min.js"></script>
<p id="nodeCount"></p>