Area Size (Diablo II)
Area Size, meaning how big places actually are, is a tricky concept to understand. Different areas in Diablo II are generated through different means. Without knowing how map generating works in Diablo II, it becomes very hard to do any assumptions based on anything but what feels bigger. There is however a lot to know on the subject.
There are three kinds of maps in Diablo II: Overworld, mazes and presets.
- Overworld areas are, just as the name suggests, everything randomly above ground (that is not a preset). Blood Moor, Lost City and the Plains of Despair all belong in this category.
- Mazes are, also as the name suggests, randomly generated dungeon. Any dungeon that changes appearance belongs here along with a few others, like the Chaos Sanctuary.
- Presets. These are defined levels. A preset never changes, but several presets can exist for the same purpose. Tristram is a preset, as are the various temples spread about Kurast.
 Map Basics
Maps in Diablo II are stored in in what are called .ds1 files. These files are then combined together to form the areas of the game. In some cases this is very easy, as is the case with presets. That is because presets are made of just a single .ds1, and figuring out the size is simply a matter of seeing how large that file is.
Mazes are a little harder to figure out. Mazes are built out of different rooms created by Blizzard. Each room thus works just like a preset, and the size of each room can be seen by just looking at the .ds1. These rooms are then randomly assembled by the game to create the famous random dungeons of Diablo II.
Overworld maps are the most complicated. Determining how big an overworld area actually is is quite hard, because it is not at all as structured and easy to understand as maze generation.
Theoretically, a map can easily be compared to any other simply by comparing the number of tiles used on each map. In practice however, comparing different kinds of areas (overworld to preset) is very hard, and getting exact comparisons is nigh impossible. Rough estimates can be made however.
Presets are the most simple forms of maps. They always look the same and don't have any random elements to them. All presets are saved as a single map file with set dimensions, therefore it's relatively easy to compare them amongst each other. Note however that the dimensions are for the box surrounding the map. An example of this is Tal Rasha's Chamber, the size listed includes the black unused tiles on the sides of the corridor.
 Preset List
|I||Cave Level 2||576||1|
|I||Underground Passage Level 2||576||1|
|I||Hole Level 2||576||1|
|I||Pit Level 2||576||1|
|I||Tower Cellar Level 5||900||2|
|I||Catacombs Level 4||682||1|
|II||Claw Viper Temple Level 2||289||1|
|II||Tal Rasha's Chamber||1,504||1|
|III||Swampy Pit Level 3||1,600||6|
|III||Flayer Dungeon Level 3||1,600||6|
|III||Kurast Sewers Level 2||396||1|
|III||Durance of Hate Level 3||1,189||1|
|V||Halls of Vaught||7,056||4|
|V||Throne of Destruction||2,080||1|
|V||The Worldstone Chamber||3,025||1|
Mazes are generally all dungeons and some other places that have a somewhat random nature to themselves. In essense, a maze can be described as several presets linked together in different ways. For example, the caves of Act I are composed of a total of 95 different "presets", commonly referred to as rooms. Whenever a dungeon is generated by the game, it uses these 95 rooms in various combinations to generate dungeons that are seemingly random each time.
For some areas, this can create very randomized layouts. For some however, there aren't that many rooms to pick from, or the random nature of the level isn't very large. The Chaos Sanctuary is technically a maze, however the only random nature are the three wings (west, north and east) where the Grand Vizier of Chaos, Lord de Seis and Infector of Souls appear. Each wing has two variations, creating eight possible variations to the Chaos Sanctuary.
 Maze Size
Size of these areas are thus determined by how many rooms a dungeon is composed off, and how large each individual room is. All rooms have the exact same dimensions in any given dungeon type (although they still suffer from the problem of black tiles like presets do), but the number of rooms can differ. This means that all dungeon rooms can be placed on a grid. Even though it often does not look like it in game, all rooms have entry-points and exit-points on the same tiles. This makes it easy to combine them together and makes it so that most rooms can be attached to any other.
Dungeon size thus depends on how many rooms a maze has, and this number can change between difficulties. One area can thus be much larger on Hell than it is on Normal. This is why the Durance of Hate Level 2 feels so much larger on Nightmare and Hell: the number of rooms are increased from 12 to 48 in the higher difficulties.
 Comparing Maze Size
This is much more vague than it is for Presets. This is first of all because the number provided below are only minimum values. The game can, and will sometimes, add extra rooms to a dungeon if it has to. The numbers are thus not exact, but may vary somewhat from game to game.
A bigger problem however is that room design varies greatly between dungeons. The Arcane Sanctuary for example is by far the largest maze in the game based on how many tiles it is composed of. However, many of those tiles are just black space that cannot be walked upon, so the actual walkable tiles are considerably smaller. This makes direct size comparisons between dungeon hard to do. However, the walking distance, meaning the amount of tiles a character has to cross in order to walk from one end of the room to the other, should still remain relative to the area size. So while the size comparisons aren't worth much in terms of measuring how many walkable tiles a dungeon includes, it does give a good estimate for the travel time the dungeon will require.
Size comparisons within a dungeon on different difficulty levels is however still quite accurate in terms of size as well, and is what the Relative Area Size on the area pages lists.
 Maze List
|Act||Area||Size||Rooms||Size (N)||Rooms (N)||Size (H)||Rooms (H)||Room Size|
|I||Den of Evil||625||1||625||1||625||1||625|
|I||Cave Level 1||2,500||4||2,500||4||2,500||4||625|
|I||Underground Passage Level 1||3,750||6||3,750||6||3,750||6||625|
|I||Hole Level 1||2,500||4||2,500||4||2,500||4||625|
|I||Pit Level 1||2,500||4||2,500||4||2,500||4||625|
|I||Tower Cellar Level 1||486||6||972||12||216||1,944||81|
|I||Tower Cellar Level 2||486||6||972||12||180||1,620||81|
|I||Tower Cellar Level 3||486||6||972||12||1,296||16||81|
|I||Tower Cellar Level 4||486||6||972||12||972||12||81|
|I||Jail Level 1||2,028||12||2,028||12||2,028||12||169|
|I||Jail Level 2||2,366||14||2,366||14||2,366||14||169|
|I||Jail Level 3||2,704||16||2,704||16||2,704||16||169|
|I||Catacombs Level 1||2,028||12||2,028||12||2,028||12||169|
|I||Catacombs Level 2||2,366||14||2,366||14||2,366||14||169|
|I||Catacombs Level 3||2,704||16||2,704||16||2,704||16||169|
|II||Lut Gholein Sewers Level 1||1,014||6||1,014||6||1,014||6||169|
|II||Lut Gholein Sewers Level 2||2,028||12||2,028||12||2,028||12||169|
|II||Lut Gholein Sewers Level 3||2,366||14||2,366||14||2,366||14||169|
|II||Harem Level 2||1,156||4||1,156||4||1,156||4||289|
|II||Palace Cellar Level 1||1,156||4||1,156||4||1,156||4||289|
|II||Palace Cellar Level 2||1,156||4||1,156||4||1,156||4||289|
|II||Palace Cellar Level 3||1,156||4||1,156||4||1,156||4||289|
|II||Stony Tomb Level 1||1,156||4||1,156||4||1,156||4||289|
|II||Stony Tomb Level 2||1,156||4||1,156||4||1,156||4||289|
|II||Halls of the Dead Level 1||1,734||6||1,734||6||1,734||6||289|
|II||Halls of the Dead Level 2||1,734||6||1,734||6||1,734||6||289|
|II||Halls of the Dead Level 3||1,734||6||1,734||6||1,734||6||289|
|II||Claw Viper Temple Level 1||3,468||12||3,468||12||3,468||12||289|
|II||Tal Rasha's Tomb||1,734||6||1,734||6||1,734||6||289|