Transparent Drawings/Zone Markings

Hello, and sorry if the answer to this is really obvious.  I've done a number of searches, and I was not able to find the answer myself. Specifically, I am looking for help on how to paint a transparent layer onto a map, in order to indicate shifting territories and gang affiliations.  Currently, whenever a drawing or image is created or placed on the map, it obscures the map beneath it.  I would very much like to paint different parts of the map with different gang colors, to indicate areas of control and danger, while still allowing players to orient themselves on the map, and the types of buildings in that zone.   Am I overlooking something dreadfully obvious?  Is there a way to do this? Thanks for any help on this.

I can think of 3 ways to do this, from least to most effort: 1) Use the aura's on some tokens.  You can make them square, they are translucent, and tokens ride on top of them. 2) Tint the map tiles.  This works if your map is broken up by those zones, tokens will also ride above them. 3) Make translucent PNGs to drop on the table.  You can do this ahead of time with some rollable table tokens allowing you to right click them and shift between no affiliation and specific gangs, plus you can add labels and other graphics.

The Aaron said: I can think of 3 ways to do this, from least to most effort: 1) Use the aura's on some tokens.  You can make them square, they are translucent, and tokens ride on top of them. 2) Tint the map tiles.  This works if your map is broken up by those zones, tokens will also ride above them. 3) Make translucent PNGs to drop on the table.  You can do this ahead of time with some rollable table tokens allowing you to right click them and shift between no affiliation and specific gangs, plus you can add labels and other graphics. #3, if you do this on the GM layer, you can see it but your vic , um, players can't.