The map has a hierarchical structure and 4 main levels, which makes the skills easier to manage. Skills are combined into related groups, groups are combined into sub-areas, and sub-areas into areas.
This enables the greater discoverability of skills by narrowing them into digestible amounts. For better understanding, consider a skill map as a world map - where you have continents (areas), countries (sub-areas), regions (groups), and skills as cities.
On an important note, the skill must appear only once on the map. A situation might occur where one skill could fall into several groups. While this might happen, a skill must only be assigned to one group (the most common) for consistency and to eliminate data redundancy. Thanks to this, it is easy to track changes and references. To highlight connections of two skills, use relations, which show the influence of one skill on another.