Is the WoT Map Rotation Broken? – a Deep Analysis and an Answer

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
Himmelsdorf 71820 7.18% Himmelsdorf (Winter)
Ruinberg 71104 4.06% Ruinberg
Prokhorovka 68125 0.05% Fiery Salient

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.

Uncategorised

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.

Remark:

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.

Solution

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.

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34 thoughts on “Is the WoT Map Rotation Broken? – a Deep Analysis and an Answer

  1. Good article +1!

    But IMO the issue of averages is that averages can be skewed.
    What should be investigated (though statistic is not my strong suite) what the median is is of the occurrence of maps, plotted versus the number of battles played, in a 24 hour cycle.

    About averages not necessarily showing correct numbers: Lets compare the street you live in.
    In your street there lives one millionaire, you and the rest of the inhabitants have a lower level of economical wealth.
    If you average economical footprint of your street, all would seem fine, it would probably show the people living there live on an above average level of economic wealth. But this average picture is skewed due to that single millionaire skewing the picture.

    Liked by 1 person

    1. yes, mines is quite a common map. kharkov and stalingrad are hardly ever seen. by me, atleast. at one point after the patch, i thought they were removed from rotation. personally, i hate mines. its too small for 15×15. for tier 1/2 or team battles its better suited.

      Like

      1. Isn’t the biggest problem with mines that the north spawn has to much of an advantage?
        From the north you can hide from arty better than from the south, one of the reason why i hate the south spawn…. Well, WG could make another way op the middle for the south but that would balance the map a bit more and that not gud. Really gud is only to take climbing options from the south team…. that’s really gud. Right WG?

        Like

    2. I think the class of your tank also plays a role what map you get.
      In lights, as an example, i get maps like prokhorovka, campinovka and steppes extremely rarely, while with meds or tds i get them quite often.

      Like

  2. “Kharkov and Stalingrad have a very low chance of occurrence. I don’t know why and I don’t have any explanation about it.”

    They were picked as the most unpopular in public polls and their frequency was lowered by WG as a result of those polls.

    Liked by 3 people

  3. Working together with server administrators on a daily basis; my theory is cache. When you fire up a map you need those maps to be loaded which leads into increased server requests. Once a map in cached in your session the number of requests for fresh maps goes down. If the server prefers to have certain maps cached to limit the strain of the server, the same maps appear more often.

    Not proven, but felt like a likely explanation.

    Liked by 3 people

    1. Adding to the theory, the re-occuring rotation of maps should then also be interruptable when you disconnect from the server, since your session then ends.

      Like

  4. I have the two other gamemodes disabled since day 1 of their introduction, yet everytime I play the game, I see the same 3 maps appearing again and again with a few others inbetween. Most common is Prokhorovka/Fiery Salient, which is especially annoying if the two follow one another.

    So in theory I should see the most spread out map types, yet I get the same ones again and again.
    Logical.

    Like

          1. tell me how ofter does that happen ?

            My experience on that map is – camp fest for 5 minutes, then the more retarded team starts pushing and majority of them dies and after that the oposite side rushes them and, if not retarded, wins the game.
            Meanwhile you canm in the middle and if nobody spotts the hill well though luck then because all you are going to do in that time is try to avoid getting 1 shot by arty (and fuck you if you are slow…)

            The only time i can have fun on that map is when the enemy team is full of retards that rush hill and you just farm them or when there is no arty and you can actually push the hill .

            I simply hate that map.
            Maps that i enjoy are Murovanka and Overlord because they are well suited for every tank you pick up (but can still be completely ruined by cancer).

            My opinion.

            Like

  5. Hi,

    this is actually a nice article. Thank you very much for it.

    Regarding your note about not having small numbers. You actually do have small numbers, if you save your replay files. You can then use WoT Replay Analyzer to see the map distribution.

    I was looking into my numbers from 9.17 and this is what I got:
    My game settings are: All game modes turned on. During the analyzed intervall I’ve played more than 99% of my games in tanks that have high tier map rotation, so no skew regarding Mittengaard or Widepark.
    498 games played since 18th of December 2016.

    A few “extremist” map occurences:
    Kharkov: 2 times.
    Stalingrad: 3 times.
    Cliff: 4 times.
    Live Oaks: 5 times.

    Ruinberg (+ clone): 22 times.
    Himmelsdorf (+clone): 24 times.
    Siegfried Line: 32 times.
    Sand River: 43 times.
    Erlenberg: 53 times.

    In version 9.16 I have a total of 609 games played. If filtered for tier 6 and above there are 547 games remaining. The same game settings apply as above.

    Let’s again check the “extremists” from before:
    Kharkov: 3 times.
    Stalingrad: 8 times.
    Cliff: 17 times.
    Live Oaks: 14 times.

    Ruinbergs: 8 times.
    Himmelsdorfs: 24 times.
    Siegfried Line: 38 times.
    Sand River: 28 times.
    Erlenberg: 25 times.

    A bit different, but we can see the same tendency that you pointed out in your article:
    Maps that have the most game modes available occur more often.
    Kharkov and Stalingrad seem to have a artificially reduced chance of occurence ( i remember WG stating in some notes that they have actually reduced the chance to get this map).

    I completely support your hypothesis that there is a “map+game mode” based rotation.
    I’d like to expand the hypothesis that there is a multi-staged map-rotation algorithm.
    1. You press “Battle”.
    2. You will be assigned a Game Mode.
    3. You (and 29 other palyers) will be assigned a Map.
    4. You will be assigned a Spawn.

    From the couple of hundred games that I’m looking into this I can say that “Standard Battle” seems to be weighed 3 times as much as Encounter or Assault:
    9.17:
    Standard Battle: 319 times
    Assault: 127 times.
    Encounter: 133 times

    9.16:
    Standard Battle: 483 times.
    Assault: 106 times.
    Encounter: 106 times.

    And depending on which game mode you are placed in, you will have a different number of maps available.

    Also, never forget the “Birthday Paradoxon” if you are talking about statistics like that.

    BR

    konzty

    Like

  6. While I appreciate the article, I think most intelligent people (not whining kids on forums) are aware that over long period of time, the map rotation evens out. That is not the issue.

    The issue is that maps are stacked – let’s say you play 2hr session of 20 battles, and instead of let’s say 12 different maps, you play 6-7 maps, one of them 4 times. That’s the issue.

    This leads to frustration, if you are in a mood to play certain tank and maps in rotation don’t fit it. You decide to play slow, well armored heavy – you get prokh/malinovka/mines/erlenberg/sand river in rotation, usually with 2 arty.
    Or you want to play your light tank or paper medium, you get kharkov/ruinberg/windstorm/siegfried line/ensk. This stacking is the issue.

    WG said couple of times that it works this way to ease the server load, which kinda might be true for EU (EU servers are very dodgy lately), but for NA/SEA where the population is so low… I’m not sure if such thing is needed.

    *tinfoil hat theory* They might be doing this intentionally. If you put bad player onto city maps 10 times, he’s most likely gonna have atleast one decent game and keep playing. On the other hand, if somebody is trying to do LT mission and all he’s getting are city maps, he’s most likely going to try again and again, waste more time. *end of tinfoil hat theory*

    Like

    1. Hi Woolgun,

      it might be a problem, true. But it’s not that bad actually. The thing is that if you expect it to happen, you will notice it if it happens, but you will not notice if it doesn’t happen.

      Here a couple stats from game sessions of a day each:
      Map Battles
      El Halluf 2
      Erlenberg 3
      Fjords 1
      Kharkov 1
      Lakeville 1
      Malinovka 1
      Prokhorovka 1
      Ruinberg 1
      Sand River 2
      Serene Coast 1
      Siegfried Line 1
      Windstorm 2
      Total 17

      Map Battles
      Ensk 2
      Fiery Salient 1
      Fjords 1
      Himmelsdorf 1
      Live Oaks 1
      Malinovka 1
      Mines 1
      Overlord 1
      Paris 1
      Winter Himmelsdorf 1
      Total 11

      Map Battles
      Cliff 1
      El Halluf 1
      Erlenberg 1
      Fiery Salient 1
      Fisherman’s Bay 1
      Fjords 1
      Malinovka 1
      Mountain Pass 1
      Pilsen 1
      Ruinberg 1
      Sacred Valley 1
      Sand River 2
      Serene Coast 1
      Siegfried Line 2
      Tundra 1
      Westfield 1
      Windstorm 1
      Winter Himmelsdorf 1
      Total 20

      Map Battles
      El Halluf 1
      Erlenberg 2
      Fisherman’s Bay 1
      Highway 1
      Karelia 3
      Lakeville 1
      Malinovka 1
      Murovanka 1
      Paris 1
      Sand River 1
      Siegfried Line 1
      Steppes 1
      Total 15

      Map Battles
      Airfield 1
      Erlenberg 2
      Himmelsdorf 1
      Karelia 2
      Lakeville 1
      Mines 2
      Murovanka 1
      Paris 2
      Prokhorovka 1
      Sacred Valley 1
      Sand River 4
      Steppes 1
      Swamp 1
      Tundra 1
      Winterberg 1
      Total 22

      Map Battles
      Arctic Region 1
      El Halluf 1
      Ensk 1
      Erlenberg 2
      Highway 1
      Karelia 1
      Lakeville 1
      Live Oaks 1
      Malinovka 2
      Mines 2
      Murovanka 2
      Prokhorovka 4
      Redshire 1
      Ruinberg 2
      Sacred Valley 1
      Sand River 4
      Serene Coast 3
      Siegfried Line 2
      Steppes 1
      Windstorm 1
      Winter Himmelsdorf 1
      Winterberg 1
      Total 36

      … the only thing i can see is that Sand River friggin spawns a lot. But see my above post for that.

      BR

      Konzty

      Like

  7. I’ve noticed that Erlenberg Encounter is rare. Also since the Paris map came out I’ve probably only played it 8 or 9 times yet I’ve seen Himmelsdorf/mines/ensk hundreds of times.

    Like

  8. While statistically every thing is OK ,as WG use BIG numbers in their sample sizes to back stuff up.
    In reality if your only playing for an Hr or 2 and only see 3 or 4 maps that is the problem.
    ,they need to sort out session map rotation, the players don’t care if over a year the rotation evens out, as they only have very short term memories, good map rotation pre session out ways good map rotation over the long term.

    Like

    1. Hi Fred G,

      sorry to tell you, but in reality what u say is not true. What you experience is “attentional bias”. You will notice that the same map comes again (and again (and again)) more than you will notice that the same map does NOT come again.

      It’s quite easy:
      After every game there is a one-out-of-N chance that you see the same map again. N is the number of total available maps. (We ignore different weighing now). Any map in the pool has the chance to occur on your next battle, even the one you played just now.
      What we see is a different version of the “Birthday Problem”. Read it on Wikipedia, if you are interested.

      According to math, if we have a map pool of 24-32 maps and all have the same chance to occur then it would only take 7 games to reach a situation where it’s a 50 / 50 chance that you will have seen a map twice.

      It’s just math.

      BR

      konzty

      Like

    2. man, i have a teory about statistics. Statistically, if you place one butcheek on a hot stow, the other on a block of ice, on average you are cozy. End of theory. Sometimes you just need to introduce a litle anarchy in the scenario.

      Like

  9. WG admitted to having only a few maps available pr battle tier every hour because of server limits. If players keep playing same tier it might feel like rotation is broken within that timespan. And that is the problem – because the random maps pretty much only work if statistics are taken in the duration of a long time period…

    Like

  10. personally i think prokhorovka and fiery salient 2 maps which are the same map and have 2 game modes which both play exactly the same except encounters less campy than standard. seriously those maps are the dullest maps in the fucking game and if your in a heavy tank your basically fuckedd because theres nothing you can do on this map. every game plays the same. if i couldd remove 3 maps from my rotation completely itd be prokhorovka and its clone as well as highway the city on this map can be a lot of fun to fight in but the other flank is terrible.

    Like

    1. Prok an Salient are certainly very similar but youtuber 4tankersanddog point out in a scouting vid there are lots of differences. Mainly elevation, humps and bumps etc which affect sightlines for TDs and the ability for lights to drop below a small ridge.

      Like

  11. It is quite a long shot to draw the conclusion that the map rotation is not broken by trying to analyse average occurrences of maps. Wargaming basically admitted that something is wrong with the map rotation, or why do they intend to fix it?
    Keep in mind that average values do not regard how the single player ends up on a single map.

    Like

  12. This is overall a sound analysis, but the problem is the scale used to average out the numbers.

    The armour is working on percentage – you get x% chance to bounce. So it is annoying to get penned by 30% shot, but it is a very limited burst of ‘wtf’. The pen happens, you lose HP, you play the rest of the game (or die), it all takes few seconds.

    In average game session though, you play like 10-15 games at most? Now I do get alot of situations when I have to play same tank on same map 3 times in a session. In 15 games session. In the same freaking tank… This is a much more annoying, I had 3 games in an arty in a row on city map, same map, few games appart in other tanks. That is half an hour taken out of my gaming time.

    And yes, it will probably average out in a 10k games, but then again the number of games needed to get it back to normal is so big that you won’t really see it. You will see the retarded map streaks though, and you will feel it when you have to play Campinovka with Maus 2-3 times in a row.

    It happens, it is annoying, even more so since it actually for some reason seems to connect tank and map into some sort of twisted joke of a gameplay…

    So yes, it is working as intended in terms of big data. And no, it is completely broken for any kind of game sessions you can have.

    Like

  13. I kiow that Stalingrad has been put on a lower spawn rate. They did a forum poll about a year back and Stalingrad came out worst. I guess they need it to be active to generate play data for it until it’s reworked. Personally I like it a lot.

    The fact that maps keep looping is probably because the servers try to minimize amount of different maps currently active. If you use memory compression it will make a lot of difference if multiple virtual server’s use the same assets already in memory. Memory IS expensive for such large clusters.

    Because matches matches overlap this can have the effect of the same maps seeming to be stuck.

    Like

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