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Welcome to this lesson in the module on charting.
I have put together some guidelines for the various charts that tableau offers and
ended up having to split the lesson into several parts.
This really is one large lesson.
But before I introduce it, let's review what we have learned so far.
We've covered the different types of charts available in tableau and
how to change their colors, shapes and sizes.
We've also discussed how to create dual layer charts and
how to use a tableau tooltip.
Now in this final set of videos,
we will focus on some guidelines you consider while creating your charts.
After you finish this lessons, you will be able to identify questions you should ask
before choosing a chart type and determine the purpose for your visualization and
you will be able to select the best charts to visualize what you're trying to say.
There's a lot to cover, so let's get started.
The place you start is with questions.
From the outset, ask yourself, what am I trying to say?
The single most important step you can take to make
a great visualization is to know what you're trying to say.
With the amount of data available today,
anyone can get lost in a world of scatter plots and geocoding.
It is vital that your visualization has a purpose and that you are selective
about what you include in your visualization to fulfill that purpose.
How do you know if your visualization has a purpose?
Well, ask some questions to find out.
Who is your audience?
What questions do they have?
What answers do you want to highlight for them?
What other questions might your visualization inspire?
What conversations may result?
The point is that your viewers should take something away from the time they spend
with your visualization Your next
order of business is to choose the right chart type.
Once you have a purpose for your visualization in mind, it is time to think
about what types of analysis will help you achieve that purpose.
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Choosing the right type of chart or graph visualization can be key to conveying
the most important insights in your data on site.
Let's revisit some of the charts available in tableau and I will
offer some guidelines or best practices regarding when to use that type of chart.
Let's start with the bar chart.
Bar charts are one of the most common ways to visualize data.
Why?
It's quick to compare information revealing highs and lows at glance.
Bar charts are especially effective when you have numerical data that splits nicely
into different categories, so you can quickly see trends within your data.
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Here are guidelines for when to use bar charts.
When comparing data across categories.
For example, when you are looking to show volume of shirts in different sizes,
website traffic by origination site or percent of spending by department.
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Showing revenue performance with bars is informative, but
overlaying color to a profitability provides immediate insight.
When you can use stacked bars or side by side bars.
Displaying related data on top of or next to each other gives depth to your analysis
and addresses multiple questions at once.
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When you can combine bar charts with maps.
Set the map to act as a filter.
So when you click on different regions, the corresponding bar
chart is displayed and when you can put bars on both sides of an axis.
Plotting both positive and
negative data points along a continuous axis is an effective way to spot trends.
4:13
Next, let's look at guidelines regarding line charts.
Line charts are right up there with bars and
pie charts as one of the most frequently used chart types.
Line charts connect individual numeric data points.
The result is a simple, straightforward way to visualize a sequence of values.
The primary use of a line chart is to display trends over a span of time.
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Here are guidelines for when to use line charts.
When viewing trends and data over time.
For example, to show how stock prices change over a five-year period,
displaying website page views during a month or revenue growth by quarter.
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When you can combine a line graph with bar charts.
A bar chart indicating the volume sold per day of a given stock combined with
a line graph of the corresponding stock price can provide visual queues for
further investigation.
When it makes sense to shade the area underlines.
When you have two or more line charts,
fill the space under the respective chart to create an area chart.
This can inform a viewer about the relative contribution that line
contributes to the whole.
5:26
Next, let's look at guidelines regarding pie charts.
Pie charts should be used to show relative proportions or percentages of information.
That's it.
Despite this narrow recommendation for when to use pies,
they are made with abandon.
As a result, they are the most commonly misused chart type.
If you're trying to compare data, leave it to bars or stacked bars.
Don't ask your viewer to translate pie wedges into relevant data or
compare one pie to another.
Key points from your data will be missed and the reader has to work too hard.
Here are guidelines regarding pie charts.
Use a pie chart when showing proportions.
For example, percentage of budget on different departments.
Response categories from a survey or
a breakdown of how Americans spend their leisure time.
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Limit pie wedge to six.
If you have more than six proportions to communicate,
consider a bar chart instead of a pie chart.
It becomes too hard to interpret the pie pieces meaningfully when
the number of wedges exceeds six.
Consider overlaying pie charts on maps.
Pies can be an interesting way to highlight geographical trends
in your data.
If you choose to use this technique,
use pies with only a couple of wedges to keep it easy to understand.
Suk S. Brar, M.B.A.Lead Business Consultant
