This is the documentation on statistical dashboards published by CZ.NIC.

Interactive Dashboards

CZ.NIC statistics are presented in the form of interactive dashboards. Each dashboard covers a specific aspect of CZ.NIC’s operation, and can be selected by clicking on its name in the menu bar at the top of the Summary page.

The dashboards combine charts, tables and text. Some areas are shared by several topics that can be switched via named tabs:

Most charts can be interacted with in different ways depending on the type of the chart. Charts in this documentation are live as well, so all features can be tested immediately here.

Some charts, whenever the mouse pointer is hovered over them, provide a toolbar near the top-right corner, such as this:

The icons represent different options for manipulating the chart or downloading either the chart as PNG image or the underlying data in the CSV format. Hovering the mouse over an icon displays a tooltip with a brief description of that tool.

Time Series

A time series chart is a data visualization tool that illustrates data points at successive intervals of time. Usually, the horizontal axis of the chart represents time and the vertical axis then the values of the observed variable(s).

Here is an example:

This chart shows four variables. Hovering the mouse over a data point on each line displays exact values of both coordinates.

The legend at the top right is interactive. Not only it specifies the mapping of line colors to variables, but also allows for turning individual variables off and on by clicking on the corresponding legend item. By double-clicking on an item, it is possible to show only that variable.

Also, by clicking on the legend, the graphic elements resize according to the selected items. For example, given the overall scale of the above graph, the TCP/53 line virtually coincides with the horizontal axis. By clicking on UDP and TCP DoT in the legend, we can remove the two dominant time series and see that TCP/53 is small but nonzero.

The extent buttons allow for selecting the length of the time period displayed, which is typically (as in this case) anchored on the right at the most recent data point.

Bar Chart

A bar chart is an efficient way for visualizing the relationship between a numeric and a categorical variable. Each discrete value of the categoric variable is represented as a bar, and the length (or height) of the bar corresponds to its numeric value.

The following graph shows a stacked bar chart in which each bar is divided into segments corresponding to multiple numeric variables:

Again, hovering the mouse over each segment displays its exact value.

A variant of the bar chart is the lollipop chart, which provides a better data-ink ratio and often helps to avoid the Moiré effect.

Sparklines

Sparklines such as are tiny charts that can be embedded in tables or text. Hovering the mouse over the line again shows the exact value at that point. Maximum and minimum values over the displayed range are indicated with orange dots.

Sankey Diagrams

A Sankey diagram is a visualisation technique that allows to display bifurcating flows, possibly in multiple stages. Several entities (nodes) are represented by labelled rectangles. Their links are represented with stripes whose width is proportional to the magnitude of the flow.

Here is a simple example:

Interactivity of this diagram is twofold:

  • hovering the mouse over one of the entities (at any stage) renders the flows sourced from or sinking to that entity in darker grey, and also displays a box with quantitative information
  • hovering the mouse over one of the stripes emphasizes the particular flow and displays info about it.

Chord Diagrams

Similar to the Sankey diagram, the chord diagram is used for visualizing mutual quantitative relationships within the same set of entities represented as segments of the circle’s perimeter. A stripe (chord) between two entities represents flows in both directions, and its width is again proportional to the magnitude of the flows.

Interactivity features also resemble the Sankey diagram (try to hover the mouse over some of the entities or flows).

Heatmap

A heatmap is a graphical representation of table-like data that augments the value in each table cell with colour hue or intensity corresponding to the value. It is able to provide an overall view of the 2D distribution of the value.

Slopegraph

A slopegraph depicts changes in multiple variables over a few discrete steps (in time, usually). It is based on the idea that humans are fairly good at interpreting relative changes between variables by comparing the slopes of line segments. Steep increases and decreases are also easily detected from the slope.

Choropleth map

A choropleth map allows for displaying the distribution of a numeric or categorical variable in the geographical map of countries or regions. It is a powerful and widely used data visualization technique that, however, has its downsides:

  • large regions tend to receive higher relative weight in visual interpretation
  • colours have no natural gradient, so comparing values visually requires moving the focus back and forth between the map and the legend.

The map can be zoomed in and out by using the mouse wheel and, again, hovering over a country or region displays an info box with detailed data.

Authenticated Access

Some graphs and statistics are not public. In order to access them, a user must log in and, in addition, be authorized for the particular dashboard. Authentication and authorization (AA) functions are available from the pull-down menu connected to the user button (top right). Selecting the Log in menu item opens the following authentication form:

Two authentication methods are supported:

After a successful login, the user menu displays new options:

Selecting Change password opens a form that allows for changing the user’s password, and Log out just does what it says. Finally, the menu item Manage tokens is mainly useful for machine access to the REST API, and is described in API Tokens.