Overlay over a map

I have a map which is a gameobject with an image on it.

Now under the map are ressources.

I want to draw a visual representation of them on my gameobject so the player can see what is where.

Ofcourse i could now draw for every field a new gameobject but it seems to create 10000 gameobjects is a very heavy operation.

So i would rather only use one gameobject and draw on it an overlay and insert it infront of my map.
How could i draw this?

To update a texture, you can use: Texture2D.SetPixels. Drawing 10000 GameObjects seems excessive, but at least they would be batched. Your alternative, drawing 10000 items onto an image doesn’t seem any better, unless it’s only done sparingly.