I am playing around with this example of a line graph using larger data values, e.g.
var data = [3567, 6643, 2123, 1447, 1245, 2414]
and the y axis isn't starting at 0, instead of 1245. Was wondering if there was a simple way to alter this.
Related
Let's take this example.
https://d3fc.io/examples/series-canvas-candlestick/
It defines X scale as a time scale.
const xScale = d3
.scaleTime()
.domain(fc.extentDate().accessors([d => d.date])(data));
To prevent multiple tick to date conversion in my zoom handler, I'd like to always work with number, but keep UI showing these numbers as dates. So, I change the code above to linear scale.
const xScale = d3
.scaleLinear()
.domain(fc.extentLinear().accessors([d => d.date.getTime()])(data));
Everything works fine, but now I have an X scale showing numbers instead of dates. The question is, how to add mapper or formatter that would show these numbers as dates in UI? I see some examples of d3.tickFormat, but not sure how to apply it in d3fc.
https://observablehq.com/#d3/axis-ticks
You supply your scales to the D3FC cartesian chart, which then couples these with the axes that it creates for you.
As mentioned in the documentation the chart exposes the properties of the X and Y axes with an x and y prefix. So, if you want to change the tick format for the X axis, which you would typically do via the tickFormat property, you instead do the following:
var chart = fc.chartCartesian(
d3.scaleLinear(),
d3.scaleLinear()
)
.xTickFormat(/* ... formatter goes here */);
I am stuck on a problem here. Could be simple though but i am having a tough time figuring it out. I want to show multiple lines on a dc composite chart.
My data is like this:
{ Name: Mike, mark1: 26.9, mark2: 62.3 },
{ Name: John, mark1: 23.5, mark2: 60.3 },
{ Name: Firen, mark1: 24.3, mark2: 62.5 }
I need the name plotted against X axis and mark1 and mark2 plotted as lines against the Y axis. I found a fiddle here which uses a linear scale to achieve the same result. http://jsfiddle.net/anmolkoul/mzx6mnru/3/
But it uses a linear scale as the base dimension is numerical. My base dimension is a string and hence not working with the same code. I figured it is due to the scale definition that i am using. Here is the fiddle that i need help with: http://jsfiddle.net/anmolkoul/pjLoh1az/1/
I have currently defined my x axis as
.x(d3.scale.ordinal().domain(nameDimension))
.xUnits(dc.units.ordinal)
I think this is where it is going wrong. I have two supplementary questions as well:
Once this is done, how to assign different colors to the lines ( it should reflect in the legend as well)
I was taking a look at the dc.js series chart, what does this line of code do?
runDimension = ndx.dimension(function(d) {return [+d.Expt, +d.Run]; });
Does it pivot the two dimensions? or is it just a quicker way of creating two crossfilter dimensions.
Thank you for the help!`
You can get the ordinal values with :
nameDimension.top(Infinity).map(function(d) {return d.Name}))
which returns ["Mike", "John", "Firen"] , then use it for the ordinal domain.
But it's not necessary, it's calculated automatically :
.x(d3.scale.ordinal())
.xUnits(dc.units.ordinal)
For colors, you can use :
dc.lineChart(lineChart1).group(mark1Group,"Mark 1").colors("#FF0000")
Here is a fiddle with those modifications : http://jsfiddle.net/1exo25u9/
I am using NVD3.js multiChart to show multiple lines and bars in the chart. All is working fine, but the x-axis labels is aligned only to the line points, not bars. I want to correctly align labels directly below the bars as it should. But I get this:
With red lines I marked where the labels should be.
I made jsFiddle: http://jsfiddle.net/n2hfN/
Thanks!
As #Miichi mentioned, this is a bug in nvd3...
I'm surprised that they have a TODO to "figure out why the value appears to be shifted" because it's pretty obvious... The bars use an ordinal scale with .rangeBands() and the line uses a linear scale, and the two scales are never made to relate to one another, except in that they share the same endpoints.
One solution would be to take the ordinal scale from the bars, and simply adjust it by half of the bar width to make the line's x-scale. That would put the line points in the center of the bars. I imagine that something similar is done in the nv.models.linePlusBarChart that #LarsKotthoff mentioned.
Basically, your line's x-scale would look something like this:
var xScaleLine = function(d) {
var offset = xScaleBars.rangeBand() / 2;
return xScaleBars(d) + offset;
};
...where xScaleBars is the x-scale used for the bar portion of the chart.
By combing through the source code for nvd3, it seems that this scale is accessible as chart.bars1.scale().
Maybe someday the authors of nvd3 will decide that their kludge of a library deserves some documentation. For now, I can show you the kind of thing that would solve the problem, by making a custom chart, and showing how the two scales would relate.
First, I'll use your data, but separate the line and bar data into two arrays:
var barData = [
{"x":0,"y":6500},
{"x":1,"y":8600},
{"x":2,"y":17200},
{"x":3,"y":15597},
{"x":4,"y":8600},
{"x":5,"y":814}
];
var lineData = [
{"x":0,"y":2},
{"x":1,"y":2},
{"x":2,"y":4},
{"x":3,"y":6},
{"x":4,"y":2},
{"x":5,"y":5}
];
Then set up the scales for the bars. For the x-scale, I'll use an ordinal scale and rangeRoundBands with the default group spacing for nvd3's multiBar which is 0.1. For the y-scale I'll use a regular linear scale, using .nice() so that the scale doesn't end on an awkward value as it does by default in nvd3. Having some space above the largest value gives you some context, which is "nice" to have when trying to interpret a chart.
var xScaleBars = d3.scale.ordinal()
.domain(d3.range(barData.length))
.rangeRoundBands([0, w], 0.1);
var yScaleBars = d3.scale.linear()
.domain([0, d3.max(barData, function(d) {return d.y;})])
.range([h, 0])
.nice(10);
Now here's the important part. For the line's x-scale, don't make a separate scale, but just make it a function of the bars' x-scale:
var xScaleLine = function(d) {
var offset = xScaleBars.rangeBand() / 2;
return xScaleBars(d) + offset;
};
Here's the complete example as a JSBin. I've tried to document the major sections with comments so it's easy to follow the overall logic of it. If you can figure out from the nvd3 source code exactly what each of the elements of the multiChart are called and how to set the individual scales of the constituent parts, then you might be able to just plug in the new scale.
My feeling on it is that you need to have a pretty good handle on how d3 works to do anything useful with nvd3, and if you want to customize it, you're probably better off just rolling your own chart. That way you have complete knowledge and control of what the element classes and variable names of the parts of your chart are, and can do whatever you want with them. If nvd3 ever gets proper documentation, maybe this will become a simple fix. Good luck, and I hope this at least helps you get started.
I'm trying to visualize 2 series but when I visualize them together, the dates don't go in sequential order anymore.
Here is the fiddle: http://jsfiddle.net/hohenheim/6R7mu/21/ Notice the weird x-axis.
Is there a way to fix the x axis on nvd3?
The data looks like this:
data1 = [{
"date": 1396828800,
"impressions": 49145385
}, {
"date": 1396915200,
"impressions": 46704447
} ....
The NVD3 "multiBarChart" uses an ordinal (category) scale, so it will only display the x-values you give it, in the order in which they are added to the scale. Because your two series only partially overlap on the x axis that's causing problems.
Unlike other NVD3 chart types, the multiBarChart doesn't give you the option of setting your own scale -- it needs to use an ordinal scale in order to generate even widths for the bars. However, you can set the x domain (the list of categories to use for each bar), by calling chart.xDomain(arrayOfXValues).
The array will need to be an ordered array of Date values that spans your data. In order to generate it, you'll need the d3 time intervals range functions. You might also need the d3.extent function to find your max and min values.
I have these labels for axis X:
1..2..3..4..5..6..etc
But I need the custom order:
3..2..5..1..6..4..etc
Even if I give the array in such custom order to d3, it automatically orders it like in the first example.
I'm using nv.models.lineChart().
The exact dump of my values:
[{"values":[{"label":18,"value":12},{"label":19,"value":412},{"label":20,"value":441},{"label":21,"value":920},{"label":22,"value":944},{"label":23,"value":144},{"label":0,"value":0},{"label":1,"value":18},{"label":2,"value":0},{"label":3,"value":7},{"label":4,"value":4},{"label":5,"value":12},{"label":6,"value":0},{"label":7,"value":0},{"label":8,"value":0},{"label":9,"value":9},{"label":10,"value":9},{"label":11,"value":32},{"label":12,"value":27},{"label":13,"value":31},{"label":14,"value":0},{"label":15,"value":30},{"label":16,"value":3},{"label":17,"value":844}],"key":"Buyings count hourly","color":"#53d488"}]