Voronoi treemap

Description

A Voronoi treemap plots points on a two-dimensional plane and draws polygons around each point such that the distance from the center point to an edge of its polygon is equal to the distance from the same edge to the point in the adjacent polygon. Polygons can be subdivided by secondary parameters. 

Required field Data type
Signals Discrete variable of any data type except ip. If you want to include IP addresses in a Voronoi diagram, be sure that they are first converted to string values in the query.
Value Number

Creating a Voronoi treemap

Here we describe how to create this chart using an example. We want to analyze the distribution of flights and flight delays depending on the airline.

The following video shows the Voronoi building process and also different ways to get additional information from the diagram:



These are the steps to follow:

  1. Go to Data Search and open the required table.

  2. Perform the required operations to get the data you want to use in the chart.

  3. Select Additional tools → Charts → Diagram → Voronoi treemap from the query toolbar.
  4. Click and drag the column headers to the corresponding fields.


  5. The Voronoi treemap is displayed. This is a visual depiction of the number of flights (the Count value) by airline over one week, with each day depicted by a number within each large cell. 

Customizing the Voronoi treemap

Several options for customizing how you want to visualize this information appear above the treemap:

  • Size by - This dropdown list contains those values specified when generating the treemap. In this example, you can choose between determining cell size based on number of flights (Count) or average flight delay (ArrivalDelayInt). 
  • Color by - By default, colors are applied randomly. Use this option if you want to apply colors based on one of the values used to generate the chart. 
  • Search - Enter text to search for a value in the Voronoi map.
  • Filter - Enter text to filter the chart by a specific value.
  • LEGEND - This is a path that lists the fields added as signals. The first signal in the path is the primary cell grouping, followed by subsequent groupings. Click and drag to change the order of the signals in the path to change the grouping order for cells in the chart.
  • VALUES - When drilling-down into the cells, this shows the values of each grouping.

Click the information icon to display a list of keyboard shortcuts that you will use to navigate the chart and to modify its style and layout:

Types of visualization

  • [T] Treemap - Cells are drawn from left to right according to their weight.
  • [F] Fisheye - The larger cells appear in the center.
  • [B] Blackhole - Smaller cells appear in the center.
  • [R] Random - The cells are randomly distributed.
  • [O] Ordered - Cells are drawn from top to bottom according to their weight. A cell's size corresponds to its weight.
  • [S] Squarified Treemap - The cells are rectangular. Cells are drawn from left to right according to their weight. A cell's size corresponds to its weight.
  • [D] Squarified Ordered - The cells are rectangular. Cells are drawn from top to bottom according to their weight. A cell's size corresponds to its weight. By default, in [F][B] and [R], a cell size does not correspond exactly to its weight (the weight is set by Count or ArrivalDelayInt). In these cases, this is the best view in order to see as many nodes as possible (the cell size is calculated using a Logarithmic function).
  • [P] Flattened / Not Flattened visualization - Flattened visualization of all branches, without having to do a drill-down. The Flattened option can be applied to all previous visualization options. Pressing P again will return it to the normal visualization.

Options applicable to all visualizations

  • Left click - Select group, again to deselect
  • CTRL + Left click - Select multiple groups
  • Left double click - Expose group
  • SHIFT + Left double click - Focus on a group. Select a group of cells and analyze them as if they were a separate Voronoi map.
  • Left click-and-hold - Open a group of cells (drill-down).
  • Right double click - Close group
  • SHIFT + Right double click - Blur group
  • Right click-and-hold - Close group
  • Mouse wheel - Zoom in / out
  • Mouse drag - Pan around zoomed visualization
  • ESC - Unexpose & close all groups
  • [G] Show / Hide detailed view
    • Displays detailed information in each cell. Left-click on the cell and then press G. A window will open to the right that will display the following information:
      • Number of children (0 if it is the last branch).
      • Total number of nodes.
      • All parents (0 if it is the top branch).
      • Aggregated values and percentage of the total.

    • Compare multiple cells:
      • By pressing CTRL + cell, you can add cells to the window on the right to compare information (children, nodes, parents and aggregated values).
      • By hovering the mouse over a cell (without clicking), it can be compared to previously added cells.

  • [%] Show / Hide percentage in the legend.
  • [V] Show / Hide value in the legend.
  • [A] Show / Hide percentage of total in the legend.
  • [Z] Show / Hide zero values.
  • [L] Calculate cell size using a logarithmic value - This is the best view in order to see as many nodes as possible. Nodes with 20% of the total weight can be the same size as nodes with 5% of the total weight.
  • [N] Calculate cell size using a value - A cell's size corresponds to its weight. Nodes with 20% of the total weight will represent 20% of map's total size, whereas nodes with 1% of the total weight may not even be seen.
  • [M] Show / Hide values as bytes.
  • [C] Show / Hide values as time (Chrono style).
  • [?] Show / Hide this help.

Other Voronoi layouts

Example 1

Visualization of flight delays (ArrivalDelayInt column) by airline over the last week.

  • Press D to apply the Squarified Ordered visualization.
  • Press N to calculate the cells size using their weight.
  • Select count in the Color by field.

The range of colors shows the number of flights (maximum is red, minimum is green) and the cell size represents the delay (the larger they are, the longer the delay).


Example 2

Visualization of the delayed arrival (ArrivalDelayInt) by airline over the last week.

  • Press G and select Alaska Airlines and AirTran Airway by clicking the cells. Move the mouse over the ATA Airlines cell to compare it to the other ones. 
  • Press G again to go back.

Export a Voronoi treemap to a dashboard

A Voronoi treemap created in a data table can be directly exported to a dashboard clicking this icon:

You have to perform an aggregation to make this option available.

After clicking it, you will see the window below. Fill the required information and click Export to send the chart to a dashboard. Click here to learn more about Devo dashboards.



These are the fields to fill in:

  • Data source
    • Name - Give a name to the data source.
    • Description - Enter a description for the data source.
    • Tags - Add tags to the data source.
    • Build From - Select the date you want events to be sent from.
    • Minimum Aggregation Period - The minimum period to be used in the data aggregation. Select between Auto1 minute5 minutes or 1 hour.
    • In real time - Check this option if you want data to be sent in real time. If not, uncheck it and select the time difference between the last event and current timestamps in the Delay field.

  • Dashboards
    • Name - Choose an already existing dashboard or create a new one.

  • Widget Name
    • Name - Enter a name for the widget.

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