Region maps are thematic maps on which boundary vector shapes are colored using a gradient; higher-intensity colors indicate higher values, and lower-intensity colors indicate lower values. These are also known as choropleth maps (https://en.wikipedia.org/wiki/Choropleth_map). Kibana offers two vector layers by default: one for countries of the world and one for US shapes. It is a new type of visualization that was introduced in Kibana 5.5.