From Ireland to Cathay (8k:4k map)

[Mad King James]

I have been trying to do a map mod for CKII for years now and I always end up unsatisfied with what I was making and abandon the idea. But this time my insane ambitions have reached epic proportions.

I am creating a map literally from Ireland to Cathay, that is 8192 pixels wide. Technical challenges will no doubt arise, performance will crawl, but this time I mean it, this map is happening.

Provinces: All important feudal caput (chief castle of holdings containing at least 100 knights fees) will be represented as their own province. Cities that have not been granted city charters yet will not exist. Bishoprics replaced with Abbeys in many parts of the world. What this means is Yorkshire is now 8 provinces, Sussex is now 6, Lincolnshire is 3 provinces, Essex is 4 etc.

I'd like to try and create another government type, purple rather than blue, for the empires of China and Byzantium, which hold cities rather than castles as primary holdings but aren't a republic. They will have lots of money but have trouble keeping up with feudal or nomadic militaries.

 

[Mad King James]

reserved

 

[Mad King James]

reserved

 

[spendabuck]

I really don't want to discourage you (this seems like a cool idea), but there's already a China mod, called Tianxia: https://forum.paradoxplaza.com/forum/index.php?threads/mod-tianxia-silk-road-expansion.816899/

 

[Mad King James]

Yeah I'm aware, that's why I stopped working on the previous map expansion I was working on, since they were doing what I was going to do but were further ahead.

This isn't just a map extension.

 

[spendabuck]

Do you think that you could also add Vinland to the map? I completely understand if you don't want to, seeing as it wasn't very important in the Middle Ages, but I just wanted to ask.

 

[Alphathon]

I also don't want to discourage you but I don't think a map of that size is possible (I'd love to make one myself if it was).

At the very least you will have to use a smaller normal map than the rest of them as the game doesn't render properly above a certain size (I don't know what the max size is @ 2:1, but @ 3:2 the largest it can be without causing issues is 4800×3200).

Other than that the game will actually load much larger maps, but you get graphical issues if you go much bigger. For one thing above a certain size the terrain ends up really low poly for some reason (i.e. you lose all of the detail in the height map).

Also, the width (and ideally the height too) must be a multiple of 512 or you will get glitching on the far east edge on large maps (it duplicates part of the west edge rather than using your data from your heightmap). As such your map would have to be 8192×4096. I'll do some quick tests and get back to you with the absolute maximum size you can use without issues.

I have also experienced an issue where on large maps you get these weird spikes at the top of the map, although I don't know the threshold for that (and the other issues) is(/are).

By the way, my mod's map is 3840×2560, which is the largest I was able to make the map (@ 3:2) without any of these issues occurring.

EDIT: I tried 5120×2560 and the map goes low-poly but the other issues do not manifest. As a side note Umbra Spherae, a mod which uses a whole world map similar to Europa Universalis, has a map @ 5632×2304 without that issue, so I believe that issues is limited by the total number of pixels.

EDIT 2: 4608×2560 also has the low-poly terrain issue, and it has fewer pixels overall, so it isn't that simple.

EDIT 3: I just tried 8192×4096, just out of interest and it definitely has the low-poly problem. It doesn't look too bad when zoomed in but when you zoom out it gets so bad that many of the islands (e.g. the Hebrides/Suðreyjar) simply disappear.

 

[Mad King James]

Yeah I found the low poly issue though I don't care :v

 

[Alphathon]

Yeah I found the low poly issue though I don't care :v

Well in that case just remember to make you normal map (world_height_normal.bmp) smaller, otherwise the game won't use your colormap and all your terrain will end up black. Oh, and be prepared for a really ugly final map.

 

[Mad King James]

Haven't had that problem so far

 

[mjohnson85]

@Alphathon All the issues you have mentioned are easy to overcome if you know how to tweak the different map elements. You have to tailor each map element to fit, but you can still end up with a really good looking map.

However, it can be an enormous amount of work depending on how detailed you want the map to be. If you are simply blowing up the map of vanilla it is just a matter of creating new the new elements (do not reuse the vanilla graphical files).

You will run into extreme time sinks if you are creating a whole new de jure map (coming from experience with detailed big maps). Also ask @Thure who I am sure will agree with this statement.

 

[Alphathon]

@Alphathon All the issues you have mentioned are easy to overcome if you know how to tweak the different map elements. You have to tailor each map element to fit, but you can still end up with a really good looking map.

However, it can be an enormous amount of work depending on how detailed you want the map to be. If you are simply blowing up the map of vanilla it is just a matter of creating new the new elements (do not reuse the vanilla graphical files).

You will run into extreme time sinks if you are creating a whole new de jure map (coming from experience with detailed big maps). Also ask @Thure who I am sure will agree with this statement.

How exactly? I have no doubt that a map could be optimally designed so that these issues have as little impact as possible, but I don't think it is possible to acceptably resolve the issue.

I think you may have misunderstood the issue though. I am aware of the glitchy coastlines and such that you can get sometimes and those can absolutely be fixed though optimal placement and height of map elements. However when the map is above a certain size the poly-count of the LOD seems to drop significantly, meaning any even reasonably small islands (like the smaller parts of the Hebrides, Bornholm etc.) and pretty much all coastlines then up jagged. Incidentally this also affects the non-LOD versions of the map; when zoomed right in it doesn't look too bad but it still doesn't look good. I had a look at your map (i.e. the one in Western Europe 1469) and it is 3712×4352. I do not believe that is large enough to trigger this problem (and it doesn't seem to). I'll try extending your map and post some screenshots to show you what I mean.

Also, to be clear, this has nothing to do with scaling. When I did my testing I did NOT scale the map up: I used canvas size in Photoshop to extend the bounds of the map to the new resolution.

Oh, and my map isn't a scaled version of the base map, it was created from scratch too. (I know all too well how long it can take.)

 

[mjohnson85]

My original map was twice the size and I reduced it because it seemed silly big (but it still looked good). Not quite sure what is leading to your issues.

***edit*** can you screenshot the issues you are specifically referring to?

 

[Alphathon]

@mjohnson85 I tried it with your map and it seems to benefit somewhat from its scale (the smallest areas are relatively insignificant ones like the Scilly Isles), so it doesn't look quite as bad as, say, the base map (which covers a much larger area and therefore has more small but significant pieces of land). I also tried expanding it both horizontally (to 8192×4096; I had to crop off the bottom of the map to make it work due to 4352 not being a multiple of 512) and uniformly (to 7424×8704) and it seems to be more heavily affected when done horizontally.

What resulted drives home what one of the issues is here: apparently the number of possible height values for the vertices is reduced along with the vertex density. This results in large areas, particularly around the low countries and the Adriatic coast of Italy near Ravenna being just below sea-level (but clipping through it).

Here is a screenshot of your map expanded to 8192×4096 (using canvas size so no interpolation etc has taken place, and therefore the RGB values in your heightmap are intact.

Now bear in mind that on your map Texel (the island directly north of mainland Holland) is 24×30 px. Now imagine how bad that would be on a map covering a larger area, so everything is relatively smaller. (On my map, which is roughly equivalent to the one in the base game in terms of area but using a different projection, Texel is 14×15.) Now, it is clear that if created with these issues in mind the map could be significantly improved, but it would (at least in my opinion) never look "good". Just to see, I also brightened all of the terrain that clips the water to 97 97 97 and this was the result:

Clearly this is a vast improvement (at least most of the land is actually land) but still doesn't look "good". Certainly it could also be improved further with enough time and effort, but looking at the shapes I feel like the vertex density is simply too low to do much better.

I did wonder whether it might be possible to modify something in gfx/FX to increase the poly count or reduce the distance LOD, but I haven't found anything yet and suspect the relevant data is hard coded.

 

[mjohnson85]

That coastal issue can be fixed with slope work, though very time consuming. You can also tweak the border files to make it cover up small issues without being overbearing.

 

[Alphathon]

That coastal issue can be fixed with slope work, though very time consuming. You can also tweak the border files to make it cover up small issues without being overbearing.

Perhaps, but given the low number of polys some territories become difficult or impossible to represent. For example, islands like Bornholm are relatively simple due to relatively simple coastlines, while others, such as Sylt, Mull and Shetland are much more irregular and distinctive. That's not to say that it would be impossible to get them to look good, but it may be impossible to be both good and accurate. Similarly, relatively narrow straits (such as the one between Anglesey and mainland Wales/Gwynedd become impossible to represent since the vertices are simply too far apart. Looking at the results of these tests, I would estimate that the vertices when fully zoomed out are probably 8px apart (it is likely to be a power of 2), and given that the number of height values appears to be reduced, you are severely limited with what you can do.

P.S. I suggest you try it yourself as well. Screenshots don't capture the full extent of the issue since it also results in flickering while zooming and only really alleviates when zoomed right in.

EDIT: I just to test my 8px hypothesis I tried scaling down and then up you height map and it would seem I am correct. When using a 8192×4096 map you effectively have a 1024×512 height map when zoomed out, which somewhat defeats the purpose of having a high-res map.

 

[Mad King James]

UK and Normandy province drawing is done, going to do titles next and history/ownership of those two areas for alpha version 0.01 coming up.

UK and Ireland has about 230 provinces and Normandy another 40

 

[marceljohn]

UK and Normandy province drawing is done, going to do titles next and history/ownership of those two areas for alpha version 0.01 coming up.

UK and Ireland has about 230 provinces and Normandy another 40

Any updates on this project? It sounds interesting.