The visualization technique is called parallel sets. For each dimension (Origin, Sex and Destination), a horizontal bar is shown for each of its possible categories. The width of the bar denotes the absolute number of matches for that category.
Starting with the first dimension (Origin), each of its categories is connected to a number of categories in the next dimension, showing how that category is subdivided. This subdividing is repeated recursively, producing a tree of “ribbons”.
Drag the dimensions and categories to reorder them. You can also click the “alpha” or “size” links that appear next to the dimension name on mouseover, to order the categories by name or frequency.
Only the first-time applications from January to July 2015 for the main origin and destination countries are used (Eurostat). Countries are sorted by their number of applicants from left to right.