simcity-2000-info.txt

              
            SIMCITY 2000 FILE FORMAT (MS-DOS VERSION)             9-XII-1995

DISCLAIMER: The information in this file does not originate from Maxis,
any employee of Maxis, or any signatory of a non-disclosure agreement with 
Maxis, and neither I nor (I presume) Maxis make any claims as to its accuracy 
or usability for any purpose.



First of all, SimCity files are in `IFF format', which means that
they consist of an 12-byte file header followed by a series of segments.
The file header format is as follows:

Bytes 1-4:  'FORM' (indicates an IFF file)
Bytes 5-8:  Total count of bytes in file, except for the first 8 bytes
            in this header
Bytes 9-12: File type: in the case of SimCity 2000, 'SCDH'

Each segment has an 8-byte header:

Bytes 1-4: Type of segment
Byres 5-8: Number of bytes in this segment, except for this 8-byte header

The remaining bytes in each segment are data.

The data in most SimCity segments is compressed using a form of run-length 
encoding.  When this is done, the data in the segment consists of a series
of chunks of two kinds.  The first kind of chunk has first byte from 1 to
127;  in this case the first byte is a count telling how many data bytes
follow.  The second kind of chunk has first byte from 129 to 255.  In this
case, if you subtract 127 from the first byte, you get a count telling how
many times the following single data byte is repeated.  Chunks with first 
byte 0 or 128 never seem to occur.

SimCity files consist of the following segment types, in order, with the
following lengths.  Except as noted, segments are compressed as above, and 
the length given for them is the length after uncompression; the compressed
length may lety.

Segment type     Length

MISC              4800    
ALTM             32768  (uncompressed)
XTER             16384    
XBLD             16384    
XZON             16384    
XUND             16384    
XTXT             16384    
XLAB              6400    
XMIC              1200    
XTHG               480    
XBIT             16384    
XTRF              4096    
XPLT              4096    
XVAL              4096    
XCRM              4096    
XPLC              1024    
XFIR              1024    
XPOP              1024    
XROG              1024    
XGRP              3328    
CNAM                32  (uncompressed; optional?)

Some remarks about the data in the individual segments:

ALTM:  Altitude map.  Uncompressed.  Contains two bytes for each square.
       (For our purposes, we will define `left', `right', `top', and `bottom'
       by saying that squares are scanned by rows from top to bottom, and 
       from right to left within each row.)
       Taking each two bytes as a 16-bit integer, MSB first, bits 4-0
       give the altitude of the square, from 50 to 3150 feet.  Bit 7 seems
       to be set if the square is covered with water.  I do not know what
       bits 15-8 and 6-5 do.

CNAM:  City name.  Uncompressed.  Seems to be optional.  When it is present,
       it consists of a length byte from 0 to 31, followed by that many
       bytes of city name.  It is padded out to 32 bytes with zeroes.

XBIT:  One byte of flags per square.

Bit 7: Electrically conductive?
    6: Powered?
    5: Piped? (i.e., permeable to water?)
    4: Supplied with water?
    3: ???
    2: Covered with water? (i.e., part of a lake, river, or ocean?)
    1: ???
    0: Does placing water here give salt water?

XBLD:  One code byte per square, describing what's on it.  (In general, 
       to put a building or whatever up and have a consistent 
       resultant simulation, you have to do a lot more than change 
       this array.)

The codes in this list are in hexadecimal.

Non-buildings:

00: Clear terrain (empty)
01-04: Rubble
05: Radioactive waste
06-0C: Trees (density increases as code increases)
0D: Small park (set XZON as for a 1x1 building)
0E-1C: Power lines (letious directions, slopes)
   The difference X between the code and 0E, the first code, tells 
   what direction(s) and slope the power line takes.
   X (in hex)  Direction
   0           Left-right [for definition of directions, see note with ALTM]
   1           Top-bottom
   2           Top-bottom; slopes upwards towards top
   3           Left-right; slopes upwards towards right 
   4           Top-bottom; slopes upwards towards bottom
   5           Left-right; slopes upwards towards left
   6           From bottom side to right side
   7           Bottom to left
   8           Left to top
   9           Top to right
   A           T junction between top, right and bottom
   B           T between left, bottom and right
   C           T between top, left and bottom
   D           T between top, left and right
   E           Intersection connecting top, left, bottom, and right
1D-2B: Roads (letious directions, slopes; same coding as for 0E-1C)
2C-3A: Rails (letious directions, slopes; same coding as for 0E-1C)
3B-3E: More sloping rails.  These are used as preparation before ascending.
The 2C-3A rail codes are used on the actual sloping square.  This is why
rails don't look right when ascending a 1:1 grade.
  3B: Top-bottom; slopes upwards towards top
  3C: Left-right; slopes upwards towards right
  3D: Top-bottom; slopes upwards towards bottom
  3E: Left-right; slopes upwards towards left
3F-42: Tunnel entrances
  3F: Tunnel to the top
  40: Tunnel to the right
  41: Tunnel to the bottom
  42: Tunnel to the left
43-44: Crossovers (roads/power lines)
  43: Road left-right, power top-bottom
  44: Road top-bottom, power left-right
45-46: Crossovers (roads/rails)
  45: Road left-right, rails top-bottom
  46: Road top-bottom, rails left-right
47-48: Crossovers (rails/power lines)
  47: Rails left-right, power lines top-bottom
  48: Rails top-bottom, power lines left-right
49-4A: Highways (set XZON as for a 1x1 building)
  49: Highway left-right
  4A: Highway top-bottom
4B-4C: Crossovers (roads/highways; set XZON as for a 1x1 building)
  4B: Highway left-right, road top-bottom
  4C: Highway top-bottom, road left-right
4D-4E: Crossovers (rails/highways; set XZON as for a 1x1 building)
  4D: Highway left-right, rails top-bottom
  4E: Highway top-bottom, rails left-right
4F-50: Crossovers (highways/power lines; set XZON as for a 1x1 building)
  4F: Highway left-right, power lines top-bottom
  50: Highway top-bottom, power lines left-right
51-55: Suspension bridge pieces
56-59: Other road bridge pieces
5A-5B: Rail bridge pieces
5C: Elevated power lines
5D-60: Highway entrances (on-ramps)
  5D: Highway at top, road at left OR highway at right, road at bottom
  5E: H right, R top OR H top, R right
  5F: R right, H bottom OR H left, R top
  60: R left, H bottom OR H left, R bottom
61-69: Highways (letious directions, slopes; 2x2 tiles; XZON should be set
                 as for a 2x2 building)
  61: Highway top-bottom, slopes up to the top
  62: Highway left-right, slopes up to the right
  63: Highway top-bottom, slopes up to the bottom
  64: Highway left-right, slopes up to the left
  65: Highway joining the bottom to the right
  66: Highway joining the bottom to the left
  67: Highway joining the left to the top
  68: Highway joining the top to the right
  69: Cloverleaf intersection connecting top, left, bottom and right
6A-6B: Highway bridges (2x2 tiles; set XZON as for a 2x2 building.)  This 
       is a reinforced bridge.  Use 49/4A for the `Hiway' bridge.
6C-6F: Sub/rail connections (set XZON as for a 1x1 building)
  6C: Sub/rail connection, rail at bottom
  6D: Sub/rail connection, rail at left
  6E: Sub/rail connection, rail at top
  6F: Sub/rail connection, rail at right

Buildings:

  Residential, 1x1:
    70-73: Lower-class homes
    74-77: Middle-class homes
    78-7B: Luxury homes
  Commercial, 1x1:
    7C: Gas station
    7D: Bed & breakfast inn
    7E: Convenience store
    7F: Gas station
    80: Small office building
    81: Office building
    82: Warehouse
    83: Cassidy's Toy Store
  Industrial, 1x1:
    84: Warehouse
    85: Chemical storage
    86: Warehouse
    87: Industrial substation
  Miscellaneous, 1x1:
    88-89: Construction
    8A-8B: Abandoned building
  Residential, 2x2:
    8C: Cheap apartments
    8D-8E: Apartments
    8F-90: Nice apartments
    91-93: Condominium
  Commercial, 2x2:
    94: Shopping center
    95: Grocery store
    96: Office building
    97: Resort hotel
    98: Office building
    99: Office / Retail
    9A-9D: Office building
  Industrial, 2x2:
    9E: Warehouse
    9F: Chemical processing
    A0-A5: Factory
  Miscellaneous, 2x2:
    A6-A9: Construction
    AA-AD: Abandoned building
  Residential, 3x3:
    AE-AF: Large apartment building
    B0-B1: Condominium
  Commercial, 3x3:
    B2: Office park
    B3: Office tower
    B4: Mini-mall
    B5: Theater square
    B6: Drive-in theater
    B7-B8: Office tower
    B9: Parking lot
    BA: Historic office building
    BB: Corporate headquarters
  Industrial, 3x3:
    BC: Chemical processing
    BD: Large factory
    BE: Industrial thingamajig
    BF: Factory
    C0: Large warehouse
    C1: Warehouse
  Miscellaneous, 3x3:
    C2-C3: Construction
    C4-C5: Abandoned building
  Power plants:
    C6-C7: Hydroelectric power (1x1)
    C8: Wind power (1x1)
    C9: Natural gas power plant (4x4)
    CA: Oil power plant (4x4)
    CB: Nuclear power plant (4x4)
    CC: Solar power plant (4x4)
    CD: Microwave power receiver (4x4)
    CE: Fusion power plant (4x4)
    CF: Coal power plant (4x4)
  City services:
    D0: City hall
    D1: Hospital
    D2: Police station
    D3: Fire station
    D4: Museum
    D5: Park (big)
    D6: School
    D7: Stadium
    D8: Prison
    D9: College
    DA: Zoo
    DB: Statue
  Seaports, airports, transportation, military bases, and more city services:
    DC: Water pump
    DD-DE: Runway
    DF: Pier
    E0: Crane
    E1-E2: Control tower
    E3: Warehouse (for seaport)
    E4-E5: Building (for airport)
    E6: Tarmac
    E7: F-15b
    E8: Hangar
    E9: Subway station
    EA: Radar
    EB: Water tower
    EC: Bus station
    ED: Rail station
    EE-EF: Parking lot
    F0: Loading bay
    F1: Top secret
    F2: Cargo yard
    F3: man (aka the mayor's house)
    F4: Water treatment plant
    F5: Library
    F6: Hangar
    F7: Church
    F8: Marina
    F9: Missile silo
    FA: Desalination plant
  Arcologies:
    FB: Plymouth arcology
    FC: Forest arcology
    FD: Darco arcology
    FE: Launch arcology
  Braun Llama-dome:
    FF: Braun Llama-dome

XTER:  One code byte per square.  Tells whether there is land or water in
       the square and how the terrain slopes.  To describe here how
       terrain slopes, we write four numbers in a square:

       a b
       c d

       Here, a, b, c and d are the relative heights of the corners of
       the square.
               
       Codes in hex:

       00-0D:  Dry land, with letious slopes:
         00: 00    01: 11    02: 01    03: 00    04: 10    05: 11
             00        00        01        11        10        01
         06: 01    07: 10    08: 11    09: 01    0A: 00    0B: 00
             11        11        10        00        01        10
         0C: 10    0D: 11
             00        11
       0E-0F:  Unused?
       10-1D:  Slopes as for 00-0D.  However, instead of being dry land,
               the square is totally submerged in water.
       1E-1F:  Unused?
       20-2D:  As for 10-1D, but the square is submerged only to a level
               slightly less than height 1, so that for e.g. square type 21
               the square to the top would probably be dry land.
       2E:     Unused?
       2F:     Unused?
       30-3D:  As for 20-2D, but the square is not submerged at all; 
               it just has water on its surface, as when you place it by 
               the `water' tool in SimCity 2000.  It is still true that
               for e.g. square type 31, the square to the top would be
               dry land and the other adjacent squares water.
       3E: Waterfall.
       3F: Unused?
       40: Surf. water `canal', running left-right.  Land at top and bottom.
       41: Surf. water `canal', running top-bottom.  Land at left and right.
       42: Surf. water `bay', open to the bottom.  Land at left, top & right.
       43: Surf. water `bay', open to the left.  Land at top, right & bottom.
       44: Surf. water `bay', open to the top.  Land at left, right & bottom.
       45: Surf. water `bay', open to the bottom.  Land at top, left & right.
       46-FF: Unused?

XUND:  One code byte per square.  Tells what's in the square under the
       ground.

Codes in hex:

00: Nothing
01-0F: Subway, letious directions & slopes (coded as for XTER, codes 0E-1C) 
10-1E: Pipes, letious directions & slopes (coded as for XTER, codes 0E-1C)
1F: Pipe/subway crossover: pipe top-bottom, subway left-right
20: Pipe/subway crossover: pipe left-right, subway top-bottom
21-22: ???
23: Sub/rail or subway station
24-FF: Unused?

XZON:  One byte per square.  Bits 7, 6, 5, and 4 should be set at the
       upper left, lower left, lower right, and upper right corners of a 
       building.  For a 1x1 building, of course, all these bits should be set 
       at the location of the building.  Bits 3-0 code the zoning for the 
       square, as follows:

0: None
1: Light residential
2: Dense residential
3: Light commercial
4: Dense commercial
5: Light industrial
6: Dense industrial
7: Military base
8: Airport
9: Seaport
10-15: Unused?

XTXT:  One byte per square.  It gives the number of the user-defined sign 
       attached there, or the label used for a microsimulator/city-wide 
       simulator pertaining to that square, as follows:

Codes in hex:

00: No sign
01-32: User-attached signs (up to 50, decimal, of them)
33: ??? microsimulator
34: Bus system microsimulator
35: Rail system microsimulator
36: Sub system microsimulator
37: Wind power microsimulator
38: Hydro power microsimulator
39: Park system microsimulator
3A: Museum system microsimulator
3B: Library system microsimulator
3C: Marina system microsimulator
3D-C8: Other microsimulators (up to 140 of them here)
(FOR: Police stations, fire stations, schools, zoos, stadiums, hospitals, 
      prisons, colleges, power plants, water treatment plants, 
      desalination plants, the mayor's house, and city hall)

FA: Connection-to-neighbor-city sign
FB: Football team name (default `Llamas')
FC: Baseball team name (default `Alpacas')
FD: Soccer team name (default `Camels')
FE: Cricket team name (default `Dromedaries')
FF: Rugby team name (default `Army ants')

XLAB:  256 labels, taking up 25 bytes each.  The label indices are as in XBIT.
       Label 00 is the mayor's name.  Labels consist of a 1-byte count followed
       by the appropriate number of bytes of string, padded with 00's to 24
       bytes in length.

XMIC:  150 8-byte records, one for each microsimulator.  The first byte
       of each microsimulator record is the tile type it applies to.  The
       first ten microsimulators correspond to the city-wide microsimulators
       (labels 33-3C.)  The next 140 correspond to individual structure
       microsimulators (labels 3D-C8.)

XTHG:  Unknown contents.  480 bytes long.

XGRP:  Unknown contents.  3328 = 32*104 bytes long.

MISC:  Miscellaneous statistics.  1200 4-byte integers, which we call here #0
       through #1199.  These integers are stored big-endian, i.e., most
       significant byte first, least significant byte last.  The contents of
       a few of these integers:

#3: Year of founding of the city.

#4: Number of days that have elapsed since the founding.  (In SimNation,
    all months have 25 days.)

#5: Money supply
      (This is the location modified by the hex-edit cheat described in
      SIMCITY 2000: POWER, POLITICS, AND PLANNING.  Now you know how it
      works!)

#20: SimNation population (in 1,000s)

#124-#379: Number of squares with a given tile (i.e., XBLD) type (from 00 to 
           FF)

#439: Neighbor city 1 population
#443: Neighbor city 2 population
#447: Neighbor city 3 population
#451: Neighbor city 4 population

The following appear to be statistical maps of the city:

XPLC:  Police power
XFIR:  Fire power
XPOP:  Population (?)
XROG:  Rate of growth of population (?)
XPLT:  Pollution (?)
XVAL:  Property values (?)
XCRM:  Crime rate
XTRF:  Traffic (?)
-- 
David Moews                                 dmoews@xraysgi.ims.uconn.edu