Analysis made by AyayaVonPotatoes
Note: Data gathered on Vbaddict on 28 of January 2017, data may change over time. This is just some of my hypothesis based on the data. If anyone has additional information to add, please do so.
Also, I don’t have the data about the map occurrence over a short period of time. (IE. getting one map over and over again) This is just looking at the problem globally.
TL;DR at the end.
We all wondered, after getting the same maps for several times, what kind of black magic is behind the map rotation algorithm. Is it biased? Why are some maps more annoying than the others? We can answer those questions by looking at the data from Vbaddict.
If you just look at the frequency of occurrence of each map, some will be surprised because some maps have significantly higher frequency of occurrence than the others. However, we can class them in 4 categories if we separated them when there’s a gap of 4000 battles.
|Category||Percentage difference in the group||Average numbers of occurence||Maps(by frequency of occurrence ,decreasing)|
|1||0.19%||62423||Siegfried Line, Erlenberg, Sand River|
|2||0.89%||51477||Mines, Ensk, Murovanka, Steppes, Redshire, Malinovka|
|3||0.14%||43830||Highway, Fjords, Sacred Valley, Arctic Region, Cliff, Windstorm, Tundra, Fisherman’s Bay, Live Oaks, Swamp, Serene Coast, Westfield, Abbey, Airfield, Mountain Pass|
|4||2.09%||36130||Pilsen, Overlord, Himmelsdorf (Winter), Ruinberg, Winterberg, Fiery Salient, Prokhorovka, Himmelsdorf|
Not categorised maps: Karelia, Kharkov, Stalingrad, Widepark, Mittengard, Paris (No Data)
Now, we can clearly see the difference between the 4 categories. Let’s look at them.
1: These 3 maps occur more often than the others by a huge margin with a very small spread out. You may already saw a pattern here; they are the maps that have all 3 game modes available: Standard, Encounter and assault.
2: Meh, nothing more to say here, they follow the same pattern here; they are the maps that have a Standard and Encounter mode
3. All the Standard maps, with the smallest spread out of 0.14%.
4. This is one of the most interesting categories, not only because of the spread out of 2.09%, the highest, but because of the nature of the maps.
Pilson and Overlord have obviously reduced frequency according to the data. My explanation for this is that both maps are being reworked, therefore, WG reduced their spawning rate.
Now the copycats. The percentage difference is inaccurate in this case:
|Variant||Total Frequency of Occurence||Percentage Difference||In favor of|
Well, now you see. Himmelsdorf is biased toward the Winter version. Ruinberg is biased toward the normal version. And Prokhorovka is basically the same.
Himmelsdorf and Ruinberg have a very similar total, but Prokorovka is miles behind. Also, their combined number of occurrence is the highest amounts the maps, Why?
Well, one of the explanation could be low tier games. Low tier players have limited access to the maps. Ruinberg and Himmelsdorf are two of them together with Mitterngard. As for Prokhorovka,
I have no bloody idea why it is so high. Edit: As /u/cwjian90 pointed out, Prokhorovka is available to Tier 2 and 3, just like the others.
Mitterngard and Widepark are low tiers exclusive maps, therefore, they can’t be used in this analysis.
Kharkov and Stalingrad have a very low chance of occurrence. I don’t know why and I don’t have any explanation about it. However, I heard someone on this sub who said that those maps aren’t available on every server. If that’s the case, then that’s why.
Karelia. Karelia is very odd because it’s the only map that only has Standard and Assault as game modes. Also oddly, its assault mode has the highest number of occurrence by map/game mode. I’m going to credit it to WG who tried to boost its frequency so that it matches the other 3 maps.
There is a lot of evidence to argue that the Map Rotation isn’t map based, but rather Map+Game mode. IE. Sand River assault, encounter and Standard count as 3 maps. Therefore, some maps are more “weighted” than others.
Finally the big question. Is the Map Rotation Broken?
Well, according to the data, it is not. Other than the 3 copycat maps, it is working as intended. No algorithm or data is perfect. The percentage difference is to be expected. However, as /u/Highdefkitten pointed out:
Huh, that really don’t reflect the erlenberg hate thing. But this proves that some maps are more weighted, strange.
Here is why: Mathematically, it is working perfectly. However, they assumed that every game mode is different gameplay wise. This is where the flaw is. Why Erlenberg is hated by the community but Siegfried Line is not? Well, we just need to look at the different game modes. Siegfried Line Assault is an east-west fight. Standard is city fight spawn in city. Encounter is a city fight spawn in the field. If we look at Erlenberg , Oh boy… North-South fight with the spawn no more than 50m apart. No wounder why people are tired of that thing. There is no gameplay change. It’s basically the same map over and over again. Therefore, Erlenberg’s meta is the most occurring one in the game.
Really, there is only one solution that is not really a solution. It is very simple: turn on and off the encounter and assault mode in your settings if you feel that a map is overwhelming you. You’ll have a higher chance of getting other maps. This is not a guaranteed method, but hey, everything is possible if you try it an infinite amount of time. You can never win against the god of RNG.
TLDR: The Map Rotation is not broken, the flaw is the map design. The Map Rotation is not map based, but rather game mode based. Theoretically, you can reduce the spawning of maps with multiple game modes by disabling the game modes in settings.