Five attributes hold the information about a tile.
These attributes are referred to as
  "type_height",
  "m1",
  "m2",
  "m3",
  "m4" and
  "m5".
The most important value is the class of a tile, stored in the upper 4 bits of the type_height array.
The lower 4 bits are used to encode the height and slope data.
For a graphical represenation of the tile-layout have a look at Landscape grid page.
OTTD's class-specific periodic tile processing routine is called once every +256 ticks for each tile.
| Class | Meaning & details of encoding | 
|---|
| 0 | 
m5 bits 4..0: tile type:
| 00 | bare land |  | 01 | 1/3 grass |  | 02 | 2/3 grass |  | 03 | full grass |  | 07 | rough land |  | 0B | rocks |  | 0F | fields; type of fields in m3 bits 3..0 (legal values: 0 through 9) |  | 10 | 1/4 snow |  | 11 | 2/4 snow |  | 12 | 3/4 snow |  | 13 | full snow |  | 15 | partial desert |  | 17 | full desert | m5 bits 7..5: update counter, incremented on every periodic processing for tile types other than 03, 07, 0B and 10 and above, on wraparound the tile is updated (for fields, the type of fields in m3 is increased, for other types the tile type in m5 is increased)
(for snow and desert, these bits are not used, tile is updated on every periodic processing)
m1: owner of the tile (normally 10)
m4 bits 7..5: type of hedge on the SW border of the tile (1 through 6, or 0=none); bits 4..2: same for the SE border
 | 
| 1 | m5 bit 7 clear: railway track 
m5 bits 7 and 6 set: railway depot / checkpointsm5 bits 0..5: track layout: bit set = track present:
| bit 0: | in the X direction |  | bit 1: | in the Y direction |  | bit 2: | in the north corner (direction W-E) |  | bit 3: | in the south corner (direction W-E) |  | bit 4: | in the west corner (direction N-S) |  | bit 5: | in the east corner (direction N-S) | m5 bit 6 set = with signals:
m3 bits 7..4: bit set = signal present:
For track in the X direction:
| bit 6: | signal in the SW direction |  | bit 7: | signal in the NE direction | For track in the Y direction:
| bit 6: | signal in the NW direction |  | bit 7: | signal in the SE direction | For tracks in the W-E direction:
| bit 4: | signal in the W direction on the track in the S corner |  | bit 5: | signal in the E direction on the track in the S corner |  | bit 6: | signal in the W direction on the track in the N corner |  | bit 7: | signal in the E direction on the track in the N corner | For tracks in the N-S direction:
| bit 4: | signal in the S direction on the track in the E corner |  | bit 5: | signal in the N direction on the track in the E corner |  | bit 6: | signal in the S direction on the track in the W corner |  | bit 7: | signal in the N direction on the track in the W corner | m2 bits 7..4: bit clear = signal shows red; same bits as in m3OpenTTD bits in m4:
| bits 2..0: | type of signal: |  | 000: | normal signals |  | 001: | pre-signals |  | 010: | exit-signals |  | 011: | combo-signals |  | 100: | PBS signals |  | bit 3: | set = semaphore signals, clear = light signals | m1: owner of the track
m2 bits 0..3:
| 0 | on bare land |  | 1 | on grass, no fences |  | 2 | fence on the NW side |  | 3 | fence on the SE side |  | 4 | fences on the NW and SE sides |  | 5 | fence on the NE side |  | 6 | fence on the SW side |  | 7 | fences on the NE and SW sides |  | 8 | fence on the E side (track in the W corner) |  | 9 | fence on the W side (track in the E corner) |  | A | fence on the S side (track in the N corner) |  | B | fence on the N side (track in the S corner) |  | C | on snow or desert | m4 bits 0..3 = track type: 0 - conventional railway, 1 - monorail, 2 - maglev
m4 bits 4..7 = Pbs reserved status:
| bits 4..6 | 'Track'number of reserved track + 1, if this is zero it means nothing is reserved on this tile |  | bit 7 | If this is set, then the opposite track ('Track'number^1) is also reserved |  
m5 value C0..C3: railway depot
m5 bits 1..0 - direction: exit towards: 00 = NE, 01 = SE, 02 = SW, 03 = NW
m5 value C4..C5: checkpoint
bit 0: clear = in X direction, set = in Y direction
 
 
m1: owner of the depot / checkpointm3 bits 0..3 = track typem3 bit 4 = use custom sprite (valid only for the checkpoint)m3 bit 6 = track on this tile is reserved by pbsm4 = custom station id | 
| 2 | m5 bits 7..4 clear: road 
m5 bit 4 set, bits 7..5 clear: level crossingm5 bits 3..0: road layout: bit set = road piece present:
| bit 0: | NW piece |  | bit 1: | SW piece |  | bit 2: | SE piece |  | bit 3: | NE piece | m1: owner of the roadm2: Index into the array of towns, 0 for non-town roadsm4 bits 0..3: counter for the roadworksm4 bits 4..6: 0 - on bare land, 1 - on grass, 2 - paved, 3 - with streetlights, 5 - tree-lined, 6 - on grass with road works, 7 - paved with road worksm4 bit 7 set = on snow or desert 
m5 bit 5 set: road depotm5 bit 3: clear - road in the X direction, set - road in the Y direction (railway track always perpendicular)m5 bit 2: set if crossing lights are onm5 bit 0: set if rail track is reserved by pbsm1: owner of the railway trackm2: Index into the array of towns, 0 for non-town roadsm3 bits 0..7: owner of the roadm4 bits 3..0: track typem4 bits 4..6: 0 - on bare land, 1 - on grass, 2 or higher - pavedm4 bit 7 set = on snow or desert 
m5 bits 3..0 - direction: exit towards: 0 = NE, 1 = SE, 2 = SW, 3 = NWm1: owner of the depotm4 bit 7 set = on snow or desert (not displayed, but set internally) | 
| 3 | Town building | 
| 4 | Trees 
m5 bits 7..6: number of trees minus onem5 bits 2..0: growth status: 0..2 - one of trees is growing, 3 - all trees are fully grown, 4..6 - one of trees is witheringm3 bits 7..0: type of trees:
(note: the actually displayed set of trees depends on both type and number of trees)| 00..0B | temperate climate trees |  | 0C..13 | sub-arctic climate trees |  | 14..1A | rainforest trees |  | 1B | cactus plants |  | 1C..1F | sub-tropical climate, non-rainforest, non-desert trees |  | 20..28 | toyland trees | m4 bits 7..5: type of hedge on the SW border of the tile (1 through 6, or 0=none)m4 bits 4..2: type of hedge on the SE border of the tile (1 through 6, or 0=none)m2 bits 5..4:
| 0 | on grass |  | 1 | on rough land |  | 2 | on snow or desert; m2 bits 7..6 - amount of snow or desert (for desert always set to 3 in TTD) | m2 bits 3..0: update counter, incremented on every periodic processing, on wraparound the growth status is updated (or, if it's 3, a random action is taken)m1: owner (normally 10) | 
| 5 | Station tile 
m5: tile type:
| 00..07 | railway station 00..01 - open platform, 02..03 - open platform with station building, 04....07 - roofed platform
 bit 0: clear = in X direction, set = in Y direction
 |  | 08..33 | large airport 
The initial layout of a large airport is (rows in Y direction, columns in X direction):| 0B | pad 1 |  | 16..19 | runway middle |  | 1A | runway ending |  | 1C | control tower |  | 20 | hangar |  | 21 | pad 3 |  | 22 | pad 2 |  | 27..32 | radar (animated) |  | 33 | transmitter |  
1F 1B 1E 33 26 1A
09 24 0B 0C 0D 16
21 1D 23 0E 0F 17
09 22 0D 11 10 18
09 08 14 13 12 19
20 0A 15 1C 27 1A
 |  | 34..41 | small airport 
The initial layout of a small airport is (rows in Y direction, columns in X direction):| 3A..3D | field with the wind meter (animated) |  | 3E | runway south ending |  | 3F | runway middle |  | 40 | runway north ending |  | 41 | hangar |  
36 3A 40
35 39 3F
34 38 3F
41 37 3E
 |  | 42 | heliport |  | 43..46 | lorry loading area;
exit towards: 43 - NE, 44 - SE, 45 - SW, 46 - NW |  | 47..4A | bus station;
exit towards: 47 - NE, 48 - SE, 49 - SW, 4A - NW |  | 4B | oilfield |  | 4C..51 | ship dock;
4C - SW coast part, 4D - NW coast part, 4E - NE coast part, 4F - SE coast part, 50 - X direction water part, 51 - Y direction water part |  | 52 | buoy |  |  | m1: owner of the stationm2: index into the array of stationsm3 bits 0..3: track type for railway stations, must be 0 for all the other stationsm3 bit 4 = use custom sprite (valid only railway stations FOR NOW)m3 bit 6 set = track is reserved by pbs (railway stations only)m4 = custom station id | 
| 6 | 
m5: tile type:
| 00 | water |  | 01 | coast or riverbank |  | 10..1B | canal locks 
| 10 | middle part, (SW-NE direction) |  | 11 | middle part, (NW-SE direction) |  | 12 | middle part, (NE-SW direction) |  | 13 | middle part, (SE-NW direction) |  | 14 | lower part, (SW-NE direction) |  | 15 | lower part, (NW-SE direction) |  | 16 | lower part, (NE-SW direction) |  | 17 | lower part, (SE-NW direction) |  | 18 | upper part, (SW-NE direction) |  | 19 | upper part, (NW-SE direction) |  | 1A | upper part, (NE-SW direction) |  | 1B | upper part, (SE-NW direction) |  |  | 80..83 | ship depots 
| 80 | ship depot, NE part (X direction) |  | 81 | ship depot, SW part (X direction) |  | 82 | ship depot, NW part (Y direction) |  | 83 | ship depot, SE part (Y direction) |  | m1: owner (for water and coasts normally 11) | 
| 7 | Void 
Tiles of this class form an invisible, one tile wide border at the south (bottom) edges of the map, so as to protect several algorithms from the consequences of a wraparound at the edges.
 | 
| 8 | Industry tile 
m5: type:
(note: this is not the same as the industry type stored in the array of industries)
 
| 00..06 | coal mine 
| 00 | wheel tower when not animated |  | 01 | wheel tower when animated; animation state in m1 bits 5..0; m1 bit 6 set = sound already generated |  |  | 07..0A | power station 
| 08 | chimney |  | 0A | transformer; animation progress in m1 bits 5..2 (valid range 0..7) |  |  | 0B..0F | sawmill |  | 10..11 | forest |  | 12..17 | oil refinery |  | 18..1C | oil rig |  | 1D..20 | oil wells 
| 1D | not animated |  | 1E..20 | various stages of animation; progress of animation in m1 bits 1..0 |  |  | 21..26 | farm |  | 27..2A | factory (temperate climate) |  | 2B..2E | printing works |  | 2F..33 | copper ore mine 
| 2F | wheel tower when not animated |  | 30 | wheel tower when animated; animation state in m1 bits 5..0; m1 bit 6 set = sound already generated |  | 31 | chimney |  |  | 34..39 | steel mill |  | 3A..3B | bank (temperate climate) |  | 3C..3F | food processing plant |  | 40..47 | paper mill |  | 48..58 | gold mine 
| 4F | wheel tower when not animated |  | 58 | wheel tower when animated; animation state in m1 bits 5..0; m1 bit 6 set = sound already generated |  |  | 59..5A | bank (sub-arctic or sub-tropical climate) |  | 5B..63 | diamond mine |  | 64..73 | iron ore mine |  | 74 | fruit plantation |  | 75 | rubber plantation |  | 76..77 | water supply |  | 78 | water tower |  | 79..7C | factory (sub-tropical climate) |  | 7D..80 | lumber mill |  | 81..82 | candyfloss forest 
| 82 | candyfloss 'trees' cut down |  |  | 83..86 | sweet factory |  | 87..88 | battery farm |  | 89 | cola wells |  | 8A..8D | toy shop |  | 8E..93 | toy factory 
| 8F | animated part; animation state in m3 (valid range 00..31) tile animation is started (m4 zeroed) on the periodic processing if field 2C in the corresponding industry array entry is nonzero
 while the animation is in progress (see the array at 04328) m4 holds the number of animation cycles that have already taken place; when this number reaches 8 the animation is stopped
 |  |  | 94..9B | plastic fountains (various stages of cyclic animation) |  | 9C..9F | fizzy drink factory |  | A0..A3 | bubble generator 
| A1 | generators |  | A2 | bubble capture facility; animation state in m3 (valid range 00..27) |  |  | A4..A6 | toffee quarry 
| A5 | animated part; animation state in m3 (valid range 00..45) |  |  | A7..AE | sugar mine 
| AE | animated part; animation state in m3 (valid range 00..5F) |  |  |  | m2: index into the array of industries
m1 bit 7: clear = under construction
m1 bits 4..2: construction counter, for buildings under construction incremented on every periodic tile processing
m1 bits 1..0: stage of construction (3 = completed), incremented when the construction counter wraps around
the meaning is different for some animated tiles which are never under construction (types 01, 1E..20, 30, 58; see above)
 | 
| 9 | m5 bits 7..4 clear: tunnel entrance/exit 
m5 bit 7 set: bridgem5 bits 3..2: 0 - railway tunnel, 1 - road tunnelm5 bits 1..0 - direction: entrance towards: 0 = NE, 1 = SE, 2 = SW, 3 = NWm1: owner of the tunnelm3 bits 3..0 = track type for railway tunnel, must be 0 for road tunnelm4 bit 7 set = on snow or desertm4 bit 0 set = track with 'Track'number 0 is reserved by pbsm4 bit 1 set = track with 'Track'number 1 is reserved by pbs 
m5 bit 6 clear: bridge ending
m5 bit 6 set: bridge middle partm5 bit 5: clear - northern, set - southern endingm3 bits 3..0 = type of track on the bridge, must be 0 for road bridgem1: owner of the bridge 
m5 bit 5 clear:
m5 bit 5 set:m5 bits 4..3: land under bridge: 0 - grass, snow or desert, 1 - water 
m5 bits 4..3: transport route under bridge: 0 - railway, 1 - roadm3 bits 7..4 = type of track on the bridge, must be 0 for road bridgem3 bits 3..0 = type of track under the bridge, if anym2 bits 3..0: bridge piece (0..5)
m1: owner of the land under bridgem5 bits 2..1: 0 - railway bridge, 1 - road bridgem5 bit 0: clear - bridge in the X direction, set - bridge in the Y directionm2 bits 7..4: bridge type:
| Type | Max. speed (mph) | Description | 
|---|
 | 0 | 20 | wooden |  | 1 | 30 | concrete |  | 2 | 40 | girder, steel |  | 3 | 50 | suspension, concrete |  | 4 | 60 | suspension, steel |  | 5 | 70 | suspension, steel |  | 6 | 100 | cantilever, steel |  | 7 | 130 | cantilever, steel |  | 8 | 150 | cantilever, steel |  | 9 | 160 | girder, steel |  | A | 200 | tubular, steel | m4 bit 7 set = on snow or desert
 | 
| A | 
m5: tile type:
| 00 | transmitter |  | 01 | lighthouse |  | 02 | company statue |  | 03 | company-owned land |  | 80..93 | company headquarters (5 sets of 4 tiles each, updated quarterly depending on the company performance) | m1: owner of the object (for lighthouses and transmitters normally 10) | 
| Classes B through F are reserved. The presence of a tile in one of the reserved classes will crash OTTD. |