The following resources and libraries are used in the development of GlottoVis:

  • ColorBrewer provides the colorschemes;
  • Leaflet is used for interactive map display;
  • D3JS is used to create the symbols on that map;
  • Bootstrap 3 is used for the menu bar and dialogs;
  • tooltipster provides the tooltips with extra information;
  • Bootstrap, tooltipster and some parts of GlottoVis are built using jQuery;
  • The icons on the homepage are from the Font Awesome project.


When opening GlottoVis, you are presented a map with circular symbols drawn on top of it.

The map

To pan the map, you can click and drag the cursor; or use the arrow keys.

To zoom in, you can scroll over the map; or press - or + (hold shift to zoom faster); or double click on the map to zoom in to that point (hold shift while double clicking to zoom out).

By holding shift while clicking and dragging the cursor, you can define an area that you are interested in viewing. Releasing the mouse button will then adjust the viewport so that the selected area is contained in it as tightly as possible.

The symbols

Every language is plotted on the map as a circle with two layers. The inner ring indicates how well documented the language is, as per its most extensive description. It can for example be the case that a grammar is available, or only a wordlist, or a phonology. The outer ring indicates how endangered a language is. This ranges from extinct to safe and one example is severly endangered. You can view all categories in the legend.

The legend is located in the bottom left corner of the map and can be toggled by clicking the button with a label icon on it. Clicking the legend will toggle its state; there are three states, depicted below: hidden, fully visible and compact.

When two symbols would overlap, they are merged into a single, slightly larger symbol. You can inspect which languages are represented by a symbol by mousing over it. This will trigger the display of a tooltip. That may look as follows.

Note that you can hover over the squares in the tooltip to see the exact category the language is in. This is illustrated above for Faroese, which is a vulnerable language.

If you are interested in more information, click a symbol.

Selecting symbols

Symbols can be selected by clicking them. A selected symbol will have a blue outline. All languages represented by the symbol will be selected, and a sidebar will be shown right of the map, in which information about all selected languages is displayed.

Clicking another symbol will automatically deselect any other languages, unless you hold ctrl while clicking. Pressing esc at any time will deselect all languages.

All languages are displayed in the sidebar sorted alphabetically by name. It may take some time before all information is loaded. A loading indicator is shown at the top of the sidebar while loading is taking place.

Language status per region

GlottoVis enables you to view the distribution of language status within a region. Thanks to GeoNames, we were able to look up in which continent most languages are located. This information can be inspected by clicking the bar chart icon in the menu bar.

A sidebar left of the map is shown, that displays two bar charts: one detailing the descriptive status of all languages, by continent; and one detailing the endangerment status. The charts display the distribution of all languages currently in view, while the distribution of all languages of the world is shown using faded colors, in the background.

The buttons below the charts can be used to adjust how they are scaled. This is depicted above, and can be used when comparisons between continents need to be made independent of the number of languages in a continent.


It is possible to click any bar of either of the charts to apply a filter to the symbols on the map.

Clicking the bar again will undo the filter. It is also possible to filter languages by name, by typing in the Item name search box and pressing enter. That only works in Google Chrome at the moment. Clear the field and press enter to clear that filter.

It is currently not possible to combine multiple filters; applying any filter will override any previously active filter. Clearing a filter will not enable that previous filter again.


To see how language documentation changed over time, you can click the calendar icon in the menu bar. This will toggle a sidebar below the map, with a stream graph / stacked bar chart visualizing the descriptive status of languages over time.

Because so few languages were documented before the sixteenth century, every document describing a language before that time is indicated explicitly with a colored disc. Mousing over these discs will show the type of documentation, the target language and the year in a tooltip.

To de-emphasize this early time period, the X-axis scale is not linear, but bilinear; the early years occupy a smaller portion of the X-axis than more recent years. This can be seen in the labeling.

The timeline can be used to filter languages on the map as well. Click and drag near the sides of the chart to filter to any time period. The Y-axis of the chart will scale so that the filtered part occupies the full height of it. This way, details in earlier years can be investigated more easily.

The discs in the early years of the timeline are hidden when they fully overlap the chart. When that happens, the changes are visible enough and the discs are no longer needed.