How to add a radar chart to Views? I'm using the Charts module to create a chart in my view (using its Views integration). But the supported chart type doesn't include Radar chart, which is what I would want it to be.

I found a sample of such chart at https://www.drupal.org/files/RadarGraph.png, which looks like so:



Is there a way I can get that to work?
Solution 1 - Using module Charts (with Views)
There is no out-of-the-box answer to your question to make this work with the Charts module, at least not as of today (yet). That's because &quot;Radar chart&quot; is not one of the currently supported chart types (those that are supported are: Pie, Bar, column, Line, Area and Scatter).
But if you're willing (and able) to complete a few extra steps, you should get it to work. Use the details below as a guide, but know also that there are so many options / features in either of the supported charting engines (libraries), i.e. Google Charts and Highcharts. Which is also why it's virtually impossible to support all those options out-of-the-box.
Option 1
Refer to the issue about Stacking column/bar charts for an example of how you can do this with a custom module. Comment #3 in it contains a sample like so:
&lt;?php
function MYMODULE_chart_alter(&amp;$chart, $chart_id) {
  dsm($chart_id); // Need Developer module enabled for dsm to work
  if ($chart_id == 'MYCHARTVIEW__DISPLAY') { // Watch out for those double underscores
    $chart['#stacking'] = TRUE;
  }
}
?&gt;

This should work for both Google Charts and Highcharts as the charting library (engine).
The remaining challenge for you is what exactly you should specify as chart_id, and which specific charting option is needed for such &quot;radar chart&quot;. My best bet, for Highcharts, is that it is what that library calls a &quot;Polar Chart&quot; (would be too easy for all those charting libraries to use at least the same terminology ...).
Option 2
A possible alternative (or maybe refinement, depends on your needs) that you may want to look at is using the approach as described in the issue about Pass library-specific options via existing #raw_options, AFTER you apply the patch in comment nr 4 of this issue. If you're using the most recent dev version of the Charts module (which is stable and includes various patches on top of the rc1 release), then this patch is already available (no more need to apply it). Be aware that this only works for Highcharts as of right now (waiting for a similar patch to become available for Google charts also).
Refer to the question about &quot;https://drupal.stackexchange.com/questions/183018&quot; (and its answers) for an interesting use-case of these &quot;raw options&quot;.
Solution 2 - Using module Forena (without Views)
The sample radar chart in your question is actually from the Supported chart types, one of the Community documentation pages from the Forena module.
The very same sample is also included in SVG Graph Demo, one of the samples that gets installed by the Forena module, such as in this demo site.
So such chart can ALSO be created with the Forena module, which uses the (free and open source) PHP SVG Graph library, without using Views. And by using the integration of Forena with the BEAN module (as explained in its documentation about Bean Integration, you can put such chart in a block that you'd put on your page where it fits your needs.
For (way) more details, head over to the Forena Documentation included with the module (or its equivalent in the demo site). Or have a look at various questions around here tagged with forena ... and add your own questions if needed (using this tag).
Disclosure: I'm a (co-)maintainer of Charts and Forena.