Comments on: Radar-XY Combination Chart

By: Exemptions

Exemptions — Wed, 06 Apr 2011 12:34:57 +0000

Thanks for acknowledging the use of radar chart to geographical coordinates. I have read blogs and stuff from experts in this field and haven’t found one that fully acknowledge this use of radar charts. Perhaps, you should help spread the words to other experts in the field of data presentation. My assumption is that you know a lot more than I do which is very much true :)

By: Jon Peltier

Jon Peltier — Fri, 01 Apr 2011 15:41:38 +0000

These are good points. The lack of continuity from last to first point is an issue, but I don’t think it’s really all that important. Forcing the line chart to wrap around into a radar chart reduces the clarity of its values more than it gains continuity through arbitrarily connecting the endpoints.

What is notable is that all of the other examples you’ve given relate the radar chart to geographical coordinates, the way radar itself is mapped to geographical coordinates. Compass headings, wind directions and velocities, tracking of storms and aircraft. For these purposes, distance and angle make more sense and are more comprehensible than converted X and Y on a line chart.

By: Exemptions

Exemptions — Fri, 01 Apr 2011 13:50:32 +0000

I know the post is old it’s worth bringing up a couple of points.
I agree that this type of chart should be avoided but SOMETIMES there may be exclusion(s) to the rule.
- Line charts sometimes can’t use used to communicate continuity of the first data point and last data point (0-24 hrs).
- “clean radar chart” for reading historical compass heading
- “clean radar chart” to track rotation of thunderstorms relative to a fixed observer at a location (basically a radar at an airport). The chart is typically called “hodograph”. If you know how to read the chart you will be able to say things about the storm’s relative motion and whether it has the potential to turn violent. Line chart can be used and one can recognize trends easy but not unique patterns which is more emphasized in a radar chart. Also you can easily orient yourself to the compass direction (0-360).
- “clean radar chart” to track predominant wind flow at a location during a 24-hour rounded clock. If you use standard line chart, you will be able to see high/lows quickly but you will have a harder time orienting yourself to the compass direction. It’s a lot easier to do that on a radar plot (0-360)

By: Jon Peltier

Jon Peltier — Tue, 19 Aug 2008 17:52:29 +0000

Gauge charts and pie charts (and probably others) suffer from being too common. People are so familiar with them, that they don’t realize the charts show nothing. Marketing tells people that it’s cool to use these displays, and people think it’s useful to use them.

By: Colin Banfield

Colin Banfield — Tue, 19 Aug 2008 15:38:59 +0000

Jon, I remember your gauge chart quite well..er…I think I have the stuff filed away in a folder somewhere ;) So many dashboard companies use these speedometer things that I think that ordinary folks believe it’s uncool not to have them (marketing can be a powerful influence sometimes). I must confess that I too was taken in initially. When one thinks of the effort it takes to emulate gauges and produce other not-so-useful charts in Excel though, it’s not even a question of diminishing returns, since the result isn’t superior to better alternatives that take less time and effort to create.

I just had a shuddering thought. Speedometers could show up in the next version of Excel!

By: Jon Peltier

Jon Peltier — Tue, 19 Aug 2008 14:55:13 +0000

Colin – Good point. For many years I had on my site a tutorial showing how to make gauge-type charts in Excel. I think I did it for laughs, to show it could be done.

The tutorial received a lot of traffic, and I received many emails, mostly from people who couldn’t figure out the math behind it. I would tell them the gauge is not a very effective chart, and they wanted to use it anyway. Finally I took the tutorial down, and replaced it with a statement explaining why it was no longer available, and why it was an ineffective means of display.

Now I receive the occasional request to send the archived page to somebody, “just this once, I promise not to abuse it”. I politely decline. To use a gauge chart is to abuse a gauge chart.