In RoP, you will be able to see multiple fortification and town levels.
Towns :
When a town level is lower or equal to 3, we called him small city
When a town level is higher than 3, we called him large city
Fortifications :
The first level of fortification will be symoblized with a wall
Fortification level 2 and higher will be symbolized with "Vauban style" defenses
There is a level 0 fortification who will be symbolized bt an entranched camp (like Pirna 1756)
Here are (from left to right)
Entranched camp | Fort level 1 | Fort level 2 and higher
+ version with supply depot
Here are (from left to right)
Small City | Small city with Fort level 1 | Small City with Fort level 2 and higher
+ version with supply depot
Here are (from left to right)
Large City | Large City with Fort level 1 | Large City with Fort level 2 and higher
+ version with supply depot