The Connectivity filter extracts cells that share common points and/or meet other connectivity criterion. (Cells that share vertices and meet other connectivity criterion such as scalar range are known as a region.) The filter works in one of six ways: 1) extract the largest connected region in the data set; 2) extract specified region numbers; 3) extract all regions sharing specified point ids; 4) extract all regions sharing specified cell ids; 5) extract the region closest to the specified point; or 6) extract all regions (used to color the data by region)