Honours Blog #22 – Modding Process: Provinces

Welcome to the second part of the Modding Process posts! These posts will go in-depth on the actual steps used as well as any considerations that need to be taken when doing it. This time I’ll be covering one of the most important aspects of EU4 Modding: Making Provinces, covering both the drawing of provinces on the provinces.bmp as well as the actual editing of the province stats itself (which was partly covered here).


Provinces Process

Drawing provinces is exactly what it sounds: drawing a shape (of a province) on Photoshop! As mentioned in the EU4 Map Modding Basics each province has its own unique RGB and ID which is stored in the adjacencies.csv file – for ease of development I kept the vanilla adjacencies and use the same RGBs they used so I can essentially copy the colours on the vanilla provinces.bmp and draw them onto my own custom one. Because of this any provinces I draw on my map will have the same statistics and name as their vanilla variant (eg if I take the RGBs for Paris and put it in my map, i’ll have the province of Paris in my map).

For this process I use Photoshop which has my master file containing all the maps and my provinces numbers.psd which contains a map of the vanilla provinces and their IDs. For editing each individual province file itself I use Notepad++ as well as the Clausewitz Scenario Editor.

Drawing the Province

  • 1. Use the Photoshop Eyedropper tool on the provinces numbers.psd and select the next ID onwards’ RGB (I go in numerical order to organize it, eg draw province ID 1 then ID 2, etc)


Drawing a province – led by an outline to be filled in soon after – note the transparent map so I can see any terrain below
  • 2. Draw the province using the RGB on the master file, for considerations:
    • -Density: the more developed or populated a province is usually dictates its size. Developed regions have smaller provinces whilst less developed ones don’t. Compare for example Europe vs the Mongolian Steppes.
    • -Natural Borders: compare with the terrain and rivers map and see if there are any hills, rivers or forests nearby that could dictate the shape of the province
    • -Internal or External: is the province well within a country? If so it doesn’t need to adhere to natural borders and can be more messy. Provinces that form the borders between two independent countries are more likely to adhere to Natural Borders as they are more defensible and a clear boundary
    • -General Vibe: not so much worldbuilding but just pure design. Is the province aesthetically pleasing/believable? For example we might have multiple provinces that are drawn vertically and look odd – why not throw a horizontal one in there to make it less like a stack of canned sardines!


  • 3. Check for any mechanical inconsistencies/faults by loading the game. Common ones include:
    • -Incorrect RGB: likely due to human error, game works but will just be an empty province
    • -Duplicate RGB: again human error, game works and province just appears twice as the same entity
    • -Stray Pixels: causes provinces to have small holes in it and look odd, can be fixed by simply going back into the photoshop file
    • -Barbed/Sharp shape: caused by drawing the province too oddly, for example a really long 1-pixel wide line that just shoots out from the middle – as a guideline I try to keep provinces as naturally smooth as possible (it’s okay for it to look slightly odd but you can generally tell if its too much)


Editing individual provinces

  • 1. Open up the Clausewitz Scenario Editor and select the province which should open up its history file


  • 2. Replace the contents with a template from an existing modified province (eg copy and paste another province’s contents into it)
(Left) Vanilla Provinces file, (Right) Modified Provinces File

In addition to this I looked at existing provinces to see their stats to help compare better:

  • -Paris has: 11 Tax, 11 Production, 10 Manpower (near our timeframe, the 1500s, Paris had around 225,000 people living in it)
  • -Venice has: 10 Tax, 12 Production, 5 Manpower (around 110,000 people. Note how Production is higher than Paris, possible due to its status as a mercantile city)
  • -London has:  8 Tax, 8 Production, 6 Manpower.
  • -London in 1741 has 18 Tax  18 Production, 8 Manpower. (London was the most populous city in the world bar Beijing, with an est. 700,000 people at this time)

Manpower is quite confusing as I originally thought it to be how population-dense a province is, but after looking at the Chinese/Indian provinces (which have a lot of people historically) they usually have 1-2 average Manpower so that obviously wasn’t the case! In the end I couldn’t find a clear definition so settled on one: the amount of fighting-fit population (this explains why high Tax/Production and historical population provinces like Chinese Nanjing with a whopping est. 487,000 population only has 3 Manpower in EU4. After all, the Chinese were known for their Confucian Bureaucracy and focus on trade whereas Europe which has higher Manpower provinces as it was all about its knightly warrior-castes, feudal wars and peasant levies)


So in terms of considerations the most important things are:

  • -Where is this province: if its a developed part of the world its got higher Tax, Production and Manpower (from vanilla province the former two usually go hand in hand, eg if a province has 8 Tax it has 8 Production).
  • -Whats the terrain type: provinces in less hospitable terrain (hills, mountains, deserts) will have lower stats whereas flatlands, coastal and river provinces will be higher (flatlands as its easier to build on, see Northern Italy – coastal as it has access to sea trade – river as it has access to river trade)
  • -What trade goods do they make, this is usually dictated by environment: (info taken from vanilla EU4)
    • -Glass, Paper or Cloth: richer urban provinces
    • -Grain, Livestock and Wool: poorer rural provinces, wool is seen in mountainous/hilly terrain
    • -Fish: coastal provinces
    • -Salt: either from some marshy provinces or from mines (can be anywhere, though mountainous/hilly terrain works well)
    • -Wine: southern/mediterranean climate provinces, usually along rivers
    • -Iron/Copper/Gold: Mountains or hill provinces
    • -Naval Supplies: some coastal provinces, or wooded inland provinces (aka strong wood for ships)
    • -Spices/Cotton/Sugar: can take place of the other rural trade goods in southern regions, Spices dominated Indonesia in history
    • -Tea: Hilly/mountainous regions of the East
    • -Tropical Wood: Forested areas of the East
    • -Gems: usually mountainous provinces, very rare!
    • -Silk: its from silkworms so the China-equivalent, though silkworms can be stolen and taken anywhere as the Byzantines did in history
    • -Chinaware: rich urban provinces in the China-equivalent, though my setting has no equivalent so maybe elven provinces?
    • -Dye: seen in Indian provinces so their equivalent in my world
    • -Incense: seen in Arabia and the East
    • -Ivory: seen in African climate regions
    • -Slaves: seen in Africa, either major sources of slaves or major slave-trading hubs. In my setting it’ll be different, the Gnolls were known slavers so their provinces will be sources of it. The Orcish Greentide will also end up with many orcs being enslaved both by their opponents and other orcs themselves.


Adding provinces to areas and regions

Each province belongs to an area, and multiple areas belong to a single region. Each region then belongs to a superregion and each superregion belongs to a continent!

For example, the province of “London” belongs to the “East Anglia” area, which belongs to the “Britain” region, which belongs to the “Western Europe” superregion which is in the continent of “Europe”.

(Left) Area Map, (Right) Region Map in my mod
(Left) Area File, (Right) Region File

Determining what provinces fit in each area is dictated by not only geography (eg they are nearby, they are all in a forest, they share a river, etc) but also culture (same peoples) and owners.

Areas form the administrative regions of EU4, in which they can either be a territory or state.

A territory can only contain temporary cores (ie they are lost when the province are lost) but can be turned into a state and gain permanent cores (though you can only have a certain number of states).

Owning all of an area is advisable as it allows you to enact Edicts that affect a wider amount of provinces as well as the fact that states can also have lower autonomy, meaning they are more efficient at generating income.



Etext.org (2007). Available at: https://web.archive.org/web/20070929110844/http://www.etext.org/Politics/World.Systems/datasets/citypop/civilizations/citypops_2000BC-1988AD (Accessed: 21 November 2017).

Ming dynasty | Chinese history (2017). Available at: https://www.britannica.com/topic/Ming-dynasty-Chinese-history (Accessed: 22 November 2017).

Leave a Reply

Your email address will not be published. Required fields are marked *