I would simply define 2 sets of coordinates: a top left and bottom right corner in world space (longitude / latitude) and a top left and bottom right corner in Unity coordinates - these coordinates define the bounding box of your playable area. By having them in both real world and in game coordinates, you can use basic interpolation mathematics to get the in-game position for real world coordinates.
I’ve found out the values of 1lat to unity meter and vice versa and same for 1lon to unity meter according the the data I had. I know that Building A has xyz coordinates (100,0,200) and lat long (20.111,50.111), can I use the conversion units to find out the lat long values? just ignore the Y axis
How accurate are you trying to be? In real world terms the curvature of the earth is significant for longditude. Your play space would need to be sepherical for this effect.
On the other hand for small localities direct mapping is fine.
Yes almost in 1km radius. I used my own conversion method, it works fine for the two points,but when i try to mark a new place according to real maps the values are quiet different