I have a chart I've created in excel that I'd like to replicate in d3, but I'm not sure where I should begin.
It's intended to show which character is speaking at which moment during a play, and so it visually looks similar to a gantt chart or stacked bar chart but it isn't working off of time the way a gantt chart would. Am I right in thinking that it'd be a bar chart or series of bar charts? Could I build it up by a series of 1 pixel wide bars, so that each pixel would equal a line in the play?
I'd provide code but I tried to modify the standard stacked bar chart and all I've really been able to do is either make the whole thing blank or modify the canvas dimensions. So I'd appreciate some suggestions to get me started.
it seems to me that the only (and big!) trouble you'll have here is creating the JSON. Once you have the JSON, it will be a piece of cake! Here is what I thought:
Create a very big JSON that is just 1 big array of hundreds of objects. Each object would be like this:
{"character": "John Doe", "place": "tavern", "duration": 5}
Then, you'll append the narrow rectangles using an ordinal scale for the places ("place") on y axis, setting the x position according to the cumulative duration of previous speeches and setting the width using the duration of each speech, and using CSS you can color the bars according to the character (using character for setting the class).
For this, you would use D3 only for the scales, avoiding the typical selection().data().enter().append() pattern and appending each rectangle in a for loop. Let me explain. Suppose you put your JSON in a variable named data. Then, you do:
for (var i = 0; i < data.length; i++){
var speech = data[i]
//rest of the code
}
This allow you, for each loop, to know the y position of the bar using speech.place, the name of the character using speech.character, for the colors, and the duration of the line using speech.duration. For calculating the x position, you declare a var duration; outside the loop and, inside it, you write:
duration += speech.duration;
In this approach, once you would use the cumulative duration for x position, the objects in the array must to be in the exact chronological order of the play.
PS: D3 is so nice that you can create an additional value named "line", for each object, with the actual line spoken by the character, and when the user hover over the rectangle he/she will see the text of the speech!
Related
I am trying to add a movable scale or axis inside a plot. For instance: in this example of stacked plot: Click-to-view
I want to include a movable y-axis scale so, if we hover the graph and put the mouse pointer on the beginning of the orange color of any bar, the a-xis will begin from that bar. (Specifically, moving x=0 line.)
I meant something like this example (of d3).
https://observablehq.com/#d3/index-chart
But, here I want to change the value of x-axis by moving the line. Is it possible to do it using vegalite? If somebody has any similar example in vegalite, can you refer it?
Thank you!
AFAIK, there is no animation in Vega Lite. However, you may check out Gemini which aims to extend the grammar of data viz to some simple animations of single-view Vega/Vega-Lite charts
Is it possible to align the data points and outliers of box plot in one straight line like in center of box plot?
Additionally, can I color the data points?
The current and the desired screen shot are attached with it.
You can use
.dataWidthPortion(0)
to not spread the points out at all. Documentation.
General advice on changing the color or style of anything, if there is no accessor for it:
Look for the chart in the chart selectors wiki, or if it's not there, inspect the item you want to change in the developer tools and find out what SVG tag and CSS class the item has. In this case, it's circle.data
Add a pretransition handler which selects the items you want, and changes them:
var cc = d3.scaleOrdinal().range(d3.schemeDark2);
bp02.on('pretransition', chart => {
chart.selectAll('circle.data').attr('fill', function(d) {
const boxDatum = d3.select(this.parentNode).datum();
return cc(boxDatum.value[d]);
})
});
In this case, we're creating an ordinal scale to map the available data to the colors in a color scheme.
The interesting question is here is what data to bind to the color of the dots, and how to get that data.
A box plot's data consists of an array of key/value pairs where each value is a Y value. When the box plot draws it will bind each circle.dot element to the index of the data in the array.
So we need to get the array that is bound to the box. Luckily d3.select(this.parentNode).datum() will give us the key/value pair for the box.
For this example, we are encoding the color based on the Y value, which we get by looking inside boxDatum.value. You don't specify how you want the dots colored but this shows the data that is available.
I'd like to have dc.js chart which slides along a selection, e.g. in the Nasdaq example https://dc-js.github.io/dc.js/ you would select a sub-selection of time then click "animate" button and the selection filter would slide along the x-axis at a pre-determined step size.
I'm a bit lost as to where one would start...does anyone have any ideas?
Most of what you need to do is set the current filter on the relevant chart based on a timer, instead of based on user interaction.
I've copied the relevant parts of the Nasdaq example into a fiddle to illustrate this: https://jsfiddle.net/0zkbyyqu/9/
Once the charts are in place, the animation is just a matter of changing the filter based on a setInterval. For obscure reasons, we want to use the focus method of the moveChart, not the filter method, but it's essentially doing the same thing, with a little more code to reflect the changes in the range chart:
var beginYear = 1985;
window.setInterval(function() {
moveChart.focus([
new Date(beginYear, 0,0,0,0,0,0),
new Date(beginYear+3, 0,0,0,0,0,0)]);
if(++beginYear > 2009)
beginYear = 1985;
}, 1000);
(If you were using the filter method, you'd have to construct a dc.filters.RangedFilter, as detailed here: Initial Range selection in DC.js chart)
I have left off your idea about the initial selection of the range coming from the user, and just gone with a range of 3 years. This example just starts animating as soon as it is loaded. You can fetch the current filter using chart.filter(); the result will be a RangedFilter, which is an array of two dates. Hopefully it is clear how to add start/stop buttons to the animation.
A couple of things are tricky about this approach:
It's tricky using a chart with transitions when you also have a timer or streaming data. In this case, I had to reduce the transitionDuration to 500ms for it to make any sense, but the cause-and-effect is still a little confusing. Not sure what to do about this.
The area chart transitions are incorrect so you get some weird artifacts.
I am creating a line chart with grid lines. Here's the similar example: http://bl.ocks.org/hunzy/11110940
I need to change the background of vertical space between X(2) to X(4), X(8) to X(10) and X(12) to X(14) on mouse hover. But I am not able to understand how to use D3 to reference those spaces between the grid lines.
There is nothing there to click on/hover over. The normal axis/grid creates lines, not rectangles. You would need to change the default behave of the axis objects to create "invisible, but clickable" rectangles in order to be able to attach a mouse event to those spaces.
I don't know if this is the recommended approach but it seems like it could work. After the axis has been created:
something
.attr('class','xaxis')
.call(xAxis)
You could select the ticks with something like this:
d3.select(svg).select('.xaxis g.tick').each(function(){
// this.transform will be "translate(X,Y)"
})
In the function you can query the existing properties of the g elements and extract the transform attribute which will contain the X and Y offset for the "tick". This can be used to determine one dimension of your rectangle objects. The other dimension is determined by the size of the other axis or something like that.
I would like to display a marker on a bullet chart even when the number is zero; however, I can't find the area in either bullet.js or bulletChart.js where I can keep it from removing the marker. This is the example that I'm implementing in my project: http://nvd3.org/examples/bullet.html
The charts work otherwise, but I just can't get that to work.
Set it to the text "0", rather than the number.
Since you're using dynamic data, you'll need to do a special case check.