I am trying to render a dc.js barChart where my y-axis is percentage 0-100% and my x-axis are numbers, however I want to order the x-axis by date.
My data looks like this:
date,trend,percent
01/01/2014 13:00,238,53.6
01/01/2014 13:15,239,64.2
01/01/2014 13:30,219,43.1
01/01/2014 13:45,219.2,43.1
01/01/2014 14:00,237.4,50.6
...
I am adding the data to crossfilter
data.forEach(function (d) { d.date = parseDate(d.date); });
var ndx = crossfilter(data);
var trendDimension = ndx.dimension(function (d) { return d.trend; });
var trendGroup = trendDimension.group().reduce(
function (p, v) {
p.time = v.date.getTime();
p.trend = +v.trend;
p.percent = +v.percent;
return p;
},
...
).order(function (p) { return p.time; }); // ??? order by time rather than trend
When I graph the dimension and group, my x-axis is sorted by trend as my x domain looks like:
var minTrend = trendDimension.bottom(1)[0].trend;
var maxTrend = trendDimension.top(1)[0].trend;
...
chart.x(d3.scale.linear().domain([minTrend, maxTrend]);
...
chart.render();
Everything plots, however the bars a sorted in order of trend and I would like them sorted in order of date/time.
Is this possible?
EDIT
I also tried:
chart.ordering(function (d) { return d.value.time; });
but that does not seem to have an effect on the ordering...
Do you want to graph percent versus trend or percent versus time?
Right now your dimension is on trend, so it will not be possible to order it by date. Crossfilter will create a bin for each trend value (which may have many dates), and the way you have written your reduce function, it will simply replace the date entry for the bin, with the last date it sees.
If you want to order by date and then use trend to affect some other aesthetic (color for example), you should use a date dimension, group by some quantization of the date, not do anything with the date in your reduce, and use date scale/xUnits.
Related
I'm implementing a 2d chart using canvas. I want to reuse d3's logic for generating the chart's axes. d3 does quite a lot of good work in generating axes and I'd like to take advantage of it.
(Note: For backward-compatibility reasons I'm stuck using d3v3 for the time being.)
Consider the following d3 code:
let scale = d3.time.scale()
.range([0, width])
.domain([lo, hi]);
let axis = d3.svg.axis()
.scale(scale)
.ticks(num_ticks)
.tickSize(10)
.orient("bottom");
I can render this into a chart div with:
svg.selectAll('.x-axis').call(axis);
I want to be able to programmatically get the tick data out of axis, including the formatted labels, by writing a function that behaves as follows:
ticks = get_axis_ticks(axis)
ticks should hold each tick position (as a Date in this particular case) and the corresponding d3-generated label.
[[Date(...), "Wed 19"],
[Date(...), "Fri 21"],
[Date(...), "Apr 23"],
[Date(...), "Tue 25"],
...]
I could then use this data to paint an axis on my canvas.
I've dug into d3v3 source (in particular here: https://github.com/d3/d3/blob/v3.5.17/src/svg/axis.js) but I find it very difficult to tease apart the logic from the SVG manipulation.
Help would be much appreciated.
One idea I have is to use the scale function you have created to generate the ticks you desire and push them into an array.
As a very simple example, if you would like 10 ticks, each incrementing by a unit of 1, you could do something like this: https://jsfiddle.net/Q5Jag/3148/
//define dummy values
var lo = 1;
var hi = 10;
var width = 512
var scale = d3.time.scale()
.range([0, width])
.domain([lo, hi]);
//define your function
var get_x_axis = function() {
let axisArr = [];
for(var i = 0; i < 10; i++ ) {
//calculate your value
axisArr.push(scale(i))
}
return axisArr
}
//call it
let axisTicks = get_x_axis()
//log it
console.log(axisTicks)
I'm not sure if this is what you're looking for, but if you need further help just ask.
I was able to get this working. I found the time formatting strategy in the d3 docs: https://github.com/d3/d3-3.x-api-reference/blob/master/Time-Formatting.md#format_multi I believe this is the strategy that d3 itself uses by default when users do not provide a custom format.
I learned that simply calling scale.ticks(N) will return Nish ticks suitable for rendering on an axis. These tick values are chosen on natural boundaries. E.g., if you're working with a time axis, these ticks will be aligned on minute, hour, day boundaries.
Here's a solution:
let time_format = d3.time.format.multi([
[".%L", d => d.getMilliseconds()],
[":%S", d => d.getSeconds()],
["%I:%M", d => d.getMinutes()],
["%I %p", d => d.getHours()],
["%a %d", d => d.getDay() && d.getDate() !== 1],
["%b %d", d => d.getDate() !== 1],
["%B", d => d.getMonth()],
["%Y", () => true]
]);
let get_ticks = (width, lo, hi, num_ticks) => {
let scale = d3.time.scale().range([0, width]).domain([lo, hi]);
return scale.ticks(num_ticks).map(t => [t, time_format(t)]);
};
Is possible to add format to the xaxis and yaxis ticks using tickformat?
The idea is cut long names of axis as:
axiswithaverylongname --> axisw...
In the plotly api reference there's and example to format dates
https://plot.ly/javascript/reference/#layout-xaxis-tickformat
and also they refer to the d3 documentation
https://github.com/d3/d3-format/blob/master/README.md
from the plotly reference:
tickformat (string)
default: ""
Sets the tick label formatting rule using d3 formatting mini-languages
which are very similar to those in Python. For numbers, see:
https://github.com/d3/d3-format/blob/master/README.md#locale_format
And for dates see: https://github.com/d3/d3-time-
format/blob/master/README.md#locale_format We add one item to d3's
date formatter: "%{n}f" for fractional seconds with n digits. For
example, "2016-10-13 09:15:23.456" with tickformat "%H~%M~%S.%2f"
would display "09~15~23.46"
As far as I know there is no way of doing it directly via tickformat but a few lines of JavaScript code will fix it for you.
Plotly.d3.selectAll(".xtick text").each(function(d, i) {
Plotly.d3.select(this).html(Plotly.d3.select(this).html().substr(0, 5));
});
Using d3's seleectAll wet get all text labels on the x-axis and update the text with the first 5 letters of the initial label.
You can either do it automatically or when the button is pressed in the example below.
var trace1 = {
x: ["A", "B1", "axiswithaverylongname", "Wow, wait a second, that's way tooooo long"],
y: [1, 2, 3, 4],
type: "bar"
};
var myPlot = document.getElementById('myPlot')
Plotly.newPlot('myPlot', [trace1]);
document.getElementById("cleanButton").addEventListener("click", function(){
Plotly.d3.selectAll(".xtick text").each(function(d, i) {
if (Plotly.d3.select(this).html().length > 8) {
Plotly.d3.select(this).html(Plotly.d3.select(this).html().substr(0, 5) + '...');
}
});
});
<script src="https://cdn.plot.ly/plotly-latest.min.js"></script>
<div id="myPlot" style="width:100%;height:100%"></div>
<button id="cleanButton">Clean x-axis</button>
I am trying to modify the chart http://bl.ocks.org/gniemetz/4618602 (D3.js).
I want remove the date format of the X axis and get numerical values of 'Gesamt' column (data.txt), example:
214-------220--------234---------255 (x axis)
I've tried to remove all occurrences of "formatDate" code, but does not work. What should I change?
Data import is happening here:
d3.csv("data.txt", function(error, data) {
data.forEach(function(d) {
d.Uhrzeit = parseDate(d.Uhrzeit);
d.Durchschn = +d.Durchschn;
d.Anz = +d.Anz;
});
d is each row or observation. If you want to use Gesamt instead of Uhrzeit, this is where you need to make the adjustments.
I have an axis where I have values:
500000
600000
1000000
2000000
D3 by default formats first two as '500k', '600k', and last two as '1.0M', '2.0M'.
I need to use only one type of unit, like getting the max value and use it as a reference for all other ticks, like get 2000000, format it like '2.0M', then the rest will be '1.0M', '0.6M', '0.5M'.
How can I achieve this?
You would need to define the desired prefix (e.g., M for millions) formatter:
var formatInteger = d3.format(".f"),
formatMillions = function (d) {
return formatInteger(d / 1e6) + "M";
};
And pass it to .tickFormat
var xAxis = d3.svg.axis()
.scale(axisScale)
.tickFormat(formatMillions);
Complete example is here.
Also, you can find more about tickFormat and formatting.
I have converted a line chart into a cumulative line chart and its y values are not displayed correctly. The range of the y axis should be 80.00 - 140.00 but instead I get -0.08 - 0.20. Has anyone managed to tweak their normalization code below to make it work with all kinds of ranges?
line.values = line.values.map(function(point, pointIndex) {
point.display = {
'y': (lines.y()(point, pointIndex) - v) / (1 + v)
};
return point;
})
Any help will be greatly appreciated.
I know that this question is somewhat old, but I am convinced that the normalization code for the cumulative line chart is not conceptually correct. Furthermore, the NVD3 cumulative line chart implementation is actually an index chart implementation (see Mike Bostock's example). A cumulative line chart would be more like this, I think. The cumulative chart can be easily achieved using the NVD3 line chart and some quick modifications to the underlying data.
If we take Bostock to be correct, and we really do wish to achieve an indexed line chart, then the indexify function in NVD3 should be changed to:
/* Normalize the data according to an index point. */
function indexify(idx, data) {
if (!indexifyYGetter) indexifyYGetter = lines.y();
return data.map(function(line, i) {
if (!line.values) {
return line;
}
var indexValue = line.values[idx];
if (indexValue == null) {
return line;
}
var v = indexifyYGetter(indexValue, idx);
// TODO: implement check below, and disable series if series
// causes a divide by 0 issue
if ((Math.abs(v) < 1e-6) && !noErrorCheck) {
// P.S. You may have to set a higher threshold (~1e-6?).
// I don't know I didn't run any tests...
line.tempDisabled = true;
return line;
}
line.tempDisabled = false;
line.values = line.values.map(function(point, pointIndex) {
point.display = {
'y': (indexifyYGetter(point, pointIndex) - v) / v
};
return point;
});
return line;
})
}
I asked a related question to the authors of NVD3 and plan to submit a pull request. Note that percentage change charts are really only meaningful when all of the underlying data is positive. When you start throwing negative values into the mix, percentage change loses all of its meaning.
What I found works is to insert another point with a y value of 0 at the beginning of the sequence of points.
Given a list of data points in the form [ [x1,y1], [x2,y2], ... [xn,yn]] ],
something like values.upshift([0,0]) works for me (the x value is arbitrary, but i just use 0 or values[0][0]) to insert to the front of the list.
(I'm getting the same thing with that chart. I'm still looking into it, but I hope this helped.)