The Importance of Data Visualization

As I’ve mentioned in previous post, I’m working on bacnethelp.com, a website dedicated to help those with a BACnet network.

The current main service is about recording the state of the network for future consultation. If you don’t really know what is a BACnet network, let’s just say that this service is comparable to recording the life signs of an individual, but for buildings. You can then see how it reacted to various stimuli, or even if it’s still alive.

However obtaining the data is only a small part of the work. The biggest part is giving it meaning. “Does the temperature changed because someone opened the window? Is this because my boiler is out of fuel?” One should seek to maximize the speed at which he can troubleshoot.

Here is a minuscule example of what a raw trend log can look like:

{:value "1159.0", :time "2009-03-02T15:45:00.000-05:00"} 
{:value "1160.0", :time "2009-03-02T16:00:00.000-05:00"} 
{:value "1161.0", :time "2009-03-02T16:15:00.000-05:00"} 
{:value "1162.0", :time "2009-03-02T16:30:00.000-05:00"} 

Quite dry isn’t it? Obviously this is not to be used directly.

Now look at how everything is instantly easier when you can see it in a graphical form.

https://frozenlock.files.wordpress.com/2012/10/wpid-objects-overview.png

Overview of multiple analog objects – bacnethelp.com

Oh my! If I had a something not working in there, I can almost guarantee it’s the first one. Did I look at the numbers? Nope, the simple shape of the graph was enough.

Of course, any children could tell you that. But why is it easier to use a graph than numeric data?

Let’s say you are looking at the number “3”. In reality your are seeing a particular shape on your screen. Your brain must then analyze it step by step to realize it is indeed the number “3”. In order, the steps taken:

  • Shape
  • Analyze
  • Realize

We shall call it the mental process.

What if you had to make a relation between many numbers? Say for example that you want to determine if a series of 20 numbers is exponential. Well now it gets more complicated, because with the realization of numbers, you will probably try to draw a graph in your head. Once you can visualize it, you will analyze it.

  • Shape
  • Analyze
  • Realize (multiplied by the 20 characters)
  • Visualize shape
  • Analyze
  • Realize

Even if we suppose that that the visualization part is effortless, we still have a total of 21 mental processes. And that’s only for 20 numbers.

If a computer were to draw the series for you, you would only be seeing a shape.

  • Shape
  • Analyze
  • Realize

A single mental process, versus 21 for the raw data. The visualization tools offers the possibilities of simplifying the data back to a single mental process regardless of the data size. The more data you have, the more the advantageous this becomes.

The same principle applies if I were to compare multiple graphs. Instead of having the previous 4 individual graphs, it could be easier to find relations by merging them together. Once again, this reduce the work our brain have to do.

https://frozenlock.files.wordpress.com/2012/10/wpid-comparison.png

Comparison of multiple analog objects – bacnethelp.com

This video (at around 2m40s) really shows the difference between the data merely ‘dumped’, versus a carefully designed representation. You will see that even if the data is the same, the difference for the user is staggering.


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