Tag Cloud (or Word Cloud) charts are initially intended to provide graphical visualization of high frequency words in a given text. Although a matter of some debate, this type of chart can, in certain circumstances, provide a faster and clearer display of data for analysis than a traditional bar or pie chart. A comparison of the chart types will be provided in the Example section.
In Contour BI, a Tag Cloud creates a visual representation of multidimensional data, particularly of dimensions, in which the font size of the dimension member depends on a selected measure (or Fact, in Contour BI terms). This chart type can be useful for Big Data Visualization, another way of saying a comparison of a large quantity of items.
In Contour BI, the font size of each word is calculated by three different methods: logarithmic, Square root and Value:
- Logarithm – Logarithmic dependence. The start font size is log(minimum value), the final font size is log (maximum value)
- Square root – Quadratic dependence. The start font size = sqrt(minimum value), the final font size = sqrt (maximum value)
- Value – Linear dependence. The start font size is the minimum value, the final font size is the maximum value
In this example we use the SQLite Sample database Chinook. The Chinook database contains data from a digital media store, invoices and customers. We will create a Tag Chart to display the media genre preferred by customers.
The report gets information from Media tables and uses the Quantity field as the main fact. This value will be used to display our chart.
- Create a database – we name it chinook
- Then we create a Schema to join different tables to get the desired data
- Create an OLAP report and define the fields of the Grid
- Part of the data is displayed in the figure below:
- Then, we create a Chart of Tag Cloud type:
- For this example, we set the weight method = Value. Some other chart properties are:
- The chart is created
- In the same slice, we create one more chart – type Bar – with the same source data
- To compare the Word Cloud with a Bar chart, we create a Dashboard report adding both charts:
Which chart would you choose for this example?