The colorful marked dots are areas that are forbidden to be built at.
As well as the Event island and Trader Forest are also forbidden to be built at.
The lines drawn within the map shouldnt be taken too serious since the map, marker and lines dont match 100% accurate. Logic is advised, if there is a redwood tree one side, tropic one on the other, you are walking on the line. If unsure if something is within your territory, check it back with an admin.