The lowest level of detail in a map is a city which will always be a point (circle/dot) as opposed to the next level up which may be a zip code (covering a wider area of geography, hence, a polygon) or a county or a state/province or country each of which would be considered a polygon or filled-map level of detail. Your data consists only of point data for City, not polygon level data which is why a filled map and only point symbolism is appearing. It is possible for a city to have polygon level data but that would be custom geometry that you'd need to locate and bring into Tableau. More on spatial files is located here: https://onlinehelp.tableau.com/current/pro/desktop/en-us/help.html#examples_spatial_files.html%3FTocPath%3DBuild%2520Cha…
If this answers your question, please mark this response as correct. Thx, Don
Can any one please send the tableau file with Bangalore city(at least 10 cities) Map.