I'm working on a radar chart and I would like to only show the last scaleline.
I found this post which could have helped me: Chart.js (Radar Chart) different scaleLineColor for each scaleLine but unfortunately, the answer is not working anymore (the jsfiddle link doesn't display anything).
I read parts of the chart.js documentation about gridLines option, then did some tests/changes on this code: [regular radar chart][2] without any result, would anyone know how to adjust it?
Thanks!
[2]: https://codepen.io/grayghostvisuals/pen/xmBpLenter code here
Here is a solution using the latest version of chart.js (v2.5.0). It uses the scale afterTickToLabelConversion callback property to overwrite the values that were set for the scale ticks (e.g. scale lines).
Since you only want to display the last line, you have to overwrite them by keeping the first tick value (which is never displayed) and only the last tick value (the last line). If you only wanted to display some other line then you would keep the first tick and only the other line that you want displayed.
Here is my implementation.
afterTickToLabelConversion: function(scaleInstance) {
// overwrite the ticks and keep the first (never shown) and last
var oldTicks = scaleInstance.ticks;
scaleInstance.ticks = [oldTicks[0], oldTicks[oldTicks.length - 1]];
// overwrite the numerical representation of the ticks and
// keep the first (never shown) and last
var oldTicksAsNumbers = scaleInstance.ticksAsNumbers;
scaleInstance.ticksAsNumbers = [oldTicksAsNumbers[0], oldTicksAsNumbers[oldTicksAsNumbers.length - 1]];
}
Here is a codepen example that shows an original radar chart and one using the approach described above so that you can see the difference.
Every example I have found shows all of the scatter plot points to be of random radii. Is it possible to have them all the same size? If I try to statically set the radius all of the circles will be very small (I'm assuming the default radius). However, if I use Math.random() as in most examples there are circles large and small. I want all the circles to be large. Is there a way to do that? Here's the code snippet forming the graph data using Math.random() (this works fine for some reason):
function scatterData(xData, yData)
{
var data = [];
for (var i = 0; i < seismoNames.length; i++)
{
data.push({
key: seismoNames[i],
values: []
});
var xVals=""+xData[i];
xVals=xVals.split(",");
var yVals=""+yData[i];
yVals=yVals.split(",");
for (var j = 0; j < xVals.length; j++)
{
data[i].values.push({
x: xVals[j],
y: yVals[j],
size: Math.random()
});
}
}
return data;
}
Math.random() spits out values between 0 and 1 such as 0.164259538891095 and 0.9842195005008699. I have tried putting these as static values in the 'size' attribute, but no matter what the circles are always really small. Is there something I'm missing?
Update: The NVD3 API has changed, and now uses pointSize, pointSizeDomain, etc. instead of just size. The rest of the logic for exploring the current API without complete documentation still applies.
For NVD3 charts, the idea is that all adjustments you make can be done by calling methods on the chart function itself (or its public components) before calling that function to draw the chart in a specific container element.
For example, in the example you linked too, the chart function was initialized like this:
var chart = nv.models.scatterChart()
.showDistX(true)
.showDistY(true)
.color(d3.scale.category10().range());
chart.xAxis.tickFormat(d3.format('.02f'));
chart.yAxis.tickFormat(d3.format('.02f'));
The .showDistX() and .showDistY() turn on the tick-mark distribution in the axes; .color() sets the series of colours you want to use for the different categories. The next too lines access the default axis objects within the chart and set the number format to be a two-digit decimal. You can play around with these options by clicking on the scatterplot option from the "Live Code" page.
Unfortunately, the makers of the NVD3 charts don't have a complete documentation available yet describing all the other options you can set for each chart. However, you can use the javascript itself to let you find out what methods are available.
Inspecting a NVD3.js chart object to determine options
Open up a web page that loads the d3 and nvd3 library. The live code page on their website works fine. Then open up your developer's console command line (this will depend on your browser, search your help pages if you don't know how yet). Now, create a new nvd3 scatter chart function in memory:
var testChart = nv.models.scatterChart();
On my (Chrome) console, the console will then print out the entire contents of the function you just created. It is interesting, but very long and difficult to interpret at a glance. And most of the code is encapsulated so you can't change it easily. You want to know which properties you can change. So run this code in the next line of your console:
for (keyname in testChart){console.log(keyname + " (" + typeof(testChart[keyname]) + ")");}
The console should now print out neatly the names of all the methods and objects that you can access from that chart function. Some of these will have their own methods and objects you can access; discover what they are by running the same routine, but replacing the testChart with testChart.propertyName, like this:
for (keyname in testChart.xAxis){console.log(keyname + " (" + typeof(testChart.xAxis[keyname]) + ")");}
Back to your problem. The little routine I suggested above doesn't sort the property names in any order, but skimming through the list you should see three options that relate to size (which was the data variable that the examples were using to set radius)
size (function)
sizeDomain (function)
sizeRange (function)
Domain and range are terms used by D3 scales, so that gives me a hint about what they do. Since you don't want to scale the dots, let's start by looking at just the size property. If you type the following in the console:
testChart.size
It should print back the code for that function. It's not terribly informative for what we're interested in, but it does show me that NVD3 follows D3's getter/setter format: if you call .property(value) you set the property to that value, but if you call .property() without any parameters, it will return back the current value of that property.
So to find out what the size property is by default, call the size() method with no parameters:
testChart.size()
It should print out function (d) { return d.size || 1}, which tells us that the default value is a function that looks for a size property in the data, and if it doesn't exist returns the constant 1. More generally, it tells us that the value set by the size method determines how the chart gets the size value from the data. The default should give a constant size if your data has no d.size property, but for good measure you should call chart.size(1); in your initialization code to tell the chart function not to bother trying to determine size from the data and just use a constant value.
Going back to the live code scatterplot can test that out. Edit the code to add in the size call, like this:
var chart = nv.models.scatterChart()
.showDistX(true)
.showDistY(true)
.color(d3.scale.category10().range())
.size(1);
chart.xAxis.tickFormat(d3.format('.02f'));
chart.yAxis.tickFormat(d3.format('.02f'));
Adding that extra call successfully sets all the dots to the same size -- but that size is definitely not 1 pixel, so clearly there is some scaling going on.
First guess for getting bigger dots would be to change chart.size(1) to chart.size(100). Nothing changes, however. The default scale is clearly calculating it's domain based on the data and then outputting to a standard range of sizes. This is why you couldn't get big circles by setting the size value of every data element to 0.99, even if that would create a big circle when some of the data was 0.01 and some was 0.99. Clearly, if you want to change the output size, you're going to have to set the .sizeRange() property on the chart, too.
Calling testChart.sizeRange() in the console to find out the default isn't very informative: the default value is null (nonexistent). So I just made a guess that, same as the D3 linear scale .range() function, the expected input is a two-element array consisting of the max and min values. Since we want a constant, the max and min will be the same. So in the live code I change:
.size(1);
to
.size(1).sizeRange([50,50]);
Now something's happening! But the dots are still pretty small: definitely not 50 pixels in radius, it looks closer to 50 square pixels in area. Having size computed based on the area makes sense when sizing from the data, but that means that to set a constant size you'll need to figure out the approximate area you want: values up to 200 look alright on the example, but the value you choose will depend on the size of your graph and how close your data points are to each other.
--ABR
P.S. I added the NVD3.js tag to your question; be sure to use it as your main tag in the future when asking questions about the NVD3 chart functions.
The radius is measured in pixels. If you set it to a value less than one, yes, you will have a very small circle. Most of the examples that use random numbers also use a scaling factor.
If you want all the circles to have a constant radius you don't need to set the value in the data, just set it when you add the radius attribute.
Not sure which tutorials you were looking at, but start here: https://github.com/mbostock/d3/wiki/Tutorials
The example "Three little circles" does a good step-by-step of the different things you can do with circles:
http://mbostock.github.io/d3/tutorial/circle.html
I have a large time series data set I need to graph, and am trying to use D3 to do it. I plan to have my graph have the x-axis be time, and allow for movement of the graph in the x direction. I want to have the graph only load/display the points that exist in the current time range on the screen.
For example, if my dataset has times 1-100, but the graph starts out with times 1-10 shown, the graph should only graph points 1-10. Then the user may move to the right and see times 5-15 and the graph should update accordingly.
Can anyone explain to me how this might be done via d3? I am having a hard time bridging the understanding from an entire data set being loaded in at once and graphed immediately to selective graphing of subsets of the data.
I think you are looking for the selection.filter() function. For example you can have:
var allNodes = vis.selectAll("Nodes").data(data.nodes);
var validNodes = allNodes.filter(function(d){return (d.time>1 && d.time <10)});
//use normal graph functions on validNodes.
You can also apply filter directly on the array of nodes.
Code
Example of my problem: http://jsfiddle.net/x46RQ/
Goal
I want the graph to be a bar graph like so: http://jsfiddle.net/Lbd85/ but obviously with dates as the x axis. If I add my data into that fiddle, it messes up like the one listed above as seen here: http://jsfiddle.net/73G7Z/
Questions
Why are all 3 days provided in the data variable not displaying?
Why are the bars not lined up with their appropriate x-axis ticks?
Why does changing the data and mode to time totally mess up what would otherwise be a functional and accurate bar graph?
Environment
jQuery 1.7.1
jQuery Mobile 1.0.1
Flot 0.7
Thanks
Let me know if any additional information is required.
Part #1, You specified a min y value of 0 in your flot options, and your data point #2 has a value of zero. So it's there but just very small, almost invisible.
Part #2, you have to offset your dates by the users timezone:
Something like this:
var tzOffset = new Date();
tzOffset = tzOffset.getTimezoneOffset()*60*1000;
data.push([(new Date("2012/02/20").getTime()-tzOffset), 1]);
Part #3, Your graph is a mess because you specified a width when in fact the option you were looking for is barWidth and you need to specify the width in terms of time, i.e. milliseconds. See here for how. Something like barWidth: 12*60*60*1000 looks OK.
So in summary, this is what it will look like: http://jsfiddle.net/ncTd3/
I am drawing a Polyline with a fairly large number of lat/lng points (~ 1000). I have two sliders (start and end) that allow the user to adjust the time bounds which then updates the Polyline to show the data between those two times.
My update algorithm goes something like this:
var mvcPath = new google.maps.MVCArray();
for (var i = 0; i < gpsData.length; i++) {
if (gpsData[i]['timestamp'] <= endDate &&
gpsData[i]['timestamp'] >= startDate) {
mvcPath.push(gpsData[i]['location']);
}
}
this.path.setPath(mvcPath);
Now the weird thing is, when I drag the end slider the line redraws as expected, however when I drag the start slider, it redraws the line correctly except at high zoom levels parts of the line seem to move slightly (it doesn't do this when zoomed in close). I thought it might be something to do with the anti alias algorithm Google applies to the Polyline but it doesn't do it when I move the end slider.
Anyone know what is causing this flickering?
I've hacked a solution which seems to work for now. I tried to keeping the number of points consistent as the API didn't seem to like me adding points to the front.
Lets say I have a set of 1000 points and I only want to show from 200 - 900. If I draw the location of point 200, 200 times then draw the rest of the data to point 900, it stops the flickering. To display 10 - 330 I would draw point 10, 10 times then draw the rest of the data to point 330.
I guess this has something to the way Google internally stores the lines of the map, if you add to the front of the line it may have to re-index a whole array and redraw the line from scratch.
I won't accept the answer for now incase someone comes up with a better answer.