Daggerfall:MAPS.BSA

MAPS.BSA is a Name Record (0x0100) BSA file containing the overland data for 62 regions of the game. The file contains 4 different record types. Each described region has one of each record type associated with it, for a total of 248 distinct records within the file. Within each of the region's associated records, all navigable settlements, dungeons, shrines, etc are listed and described.

General File Layout

Each described region has 4 records associated with it. Records are all named in 7-bit ASCII string DOS8.3 format. The 3 character record extension is the ASCII representation of the region's decimal number, with leading 0's. Ex: Daggerfall (0x11) is identified by records ending with "017", such as "MAPPITEM.017". The leading 8 characters indicate the specific type of record:

MapNames

These records simply lists the names of all navigable locations within the region, stored as an array of 7-bit ASCII strings.

MapTable

These records describe the coarse GPS data, and type of the navigable locations within the region.

MapPItem

These records describe the exterior of each navigable location within the region.

MapDItem

These records describe the dungeon interiors of each navigable location within the region.

Ex: "MAPNAMES.005" is the list of the names of all navigable places within Dwynnen.

Location Name Record (MapNames)

This type of record contains the count of all navigable locations within the record's associated region, immediately followed by the names of all navigable locations within the record's associated region.

The first four bytes are the count of name elements as an UInt32, referred to as LocationCount. This record is variably sized, but must always be 4 + ( 32 * LocationCount ) bytes long.

Immediately following this count are the actual names of all the navigable locations for the record's associated region, each 32 characters wide, stored as a null-terminated, 7-bit ASCII string. There are exactly LocationCount elements.

Location GPS Record (MapTable)

These records report the GPS location data, as well as the type of the described location, for each navigable location within the record's associated region. Each record consists of a contiguous list of MapTable structures. Each MapTable structure is 17 bytes long in size.

There are exactly MapNames.LocationCount elements in the contained list, and each indexed record is the same location as in the map names.

MapTable Element structure

Offset	Type	Name	Description
0-3	Int32	MapId	This numeric ID is used to associate values MapTable elements with LocationRecordElement elements. Each LocationExterior value must be described by a MapTable value. The first 20 bits of this field matches the first 20 bits of a LocationExterior.ExteriorData.MapId value; Simply match ( LocationExterior.ExteriorData.MapId & 0x000fffff ) with ( MapTable.MapId & 0x000fffff ).
4	UInt8	Unknown1	Unknown purpose
5-8	UInt32	LongitudeType	This field is actually the combination of the location's Longitude and type. Decoding instructions are below.
9-10	UInt16	Latitude	The location's latitude.
11-12	UInt16	Unknown2	Unknown purpose.
13-16	UInt32	Unknown3	Unknown purpose.

Decoding the LogitudeType field

bits	Field	Code
0-17	Longitude	LongitudeType & 0x1ffff
18-31	Type	LongitudeType >> 17

Location Item Records

Basic Structure

The remaining two types of records (MapPItem and MapDItem) each use a common base format for their root data, described here. Each record consists of a contiguous list of the data for all the navigable locations for that record's associated region. Since not all locations have dungeons, Location Exterior Data Records may contain more elements than Dungeon Interior Data Records.

The base format, LocationRecordElement, is variably-sized. It consists of a DoorHeader, immediately followed by a contiguous list of zero or more Door elements, immediately followed by a LocationRecordElementHeader.

LocationRecordElement coarse structure

DoorHeader
*Door
LocationRecordElementHeader

DoorHeader

DoorHeader structure

Offset	Type	Name	Description
0-3	UInt32	DoorCount	The count of Door elements which immediately follow this header as a contiguous list.

Door

Immediately following the DoorHeader is a contiguous list of Door elements, DoorCount in count, each 6 bytes long.

Door structure

Offset	Type	Name	Description
0-1	UInt16	BuildingDataIndex	This is a valid index to an element within the LocationExterior.BuildingData array, or 0xffff which indicates this Door is not associated with an element of the BuildingData array. This places a maximum count of BuildingData elements at 0x7fff.
2	UInt8	NullValue	This value is always 0x00.
3	UInt8	Mask	This value is a mask of some type. The specific purpose is presently unknown.
4	UInt8	Unknown1	Unknown Purpose
5	UInt8	Unknown2	Unknown Purpose

LocationRecordElementHeader

The LocationRecordElementHeader immediately follows the contiguous list of Door elements. Each LocationRecordElementHeader structure is 112 bytes long.

LocationRecordElementHeader structure

Offset	Type	Name	Description
0-3	UInt32	AlwaysOne1	This value is always 0x00000001 for all records.
4-5	UInt16	NullValue1	This value is always 0x0000 for all records.
6	UInt8	NullValue2	This value is always 0x00 for all records.
7-10	Int32	Y	This is the Y coordinate for the location in game world units. It's 256 times the longitude plus 0-255.
11-14	UInt32	NullValue3	This value is always 0x00000000 for all records.
15-18	Int32	X	This is the X coordinate for the location in game world units. It's 256 times the latitude plus 0-255.
19-20	UInt16	IsExterior	This value is an enumeration. Since there are only two valid values (described below), this may be treated as a Bool16.
21-22	UInt16	NullValue4	This value is always 0x0000 for all records.
23-26	UInt32	Unknown1	Unknown Purpose.
27-30	UInt32	Unknown2	Unknown Purpose.
31-32	UInt16	AlwaysOne2	Always 0x0001 for all records.
33-34	UInt16	LocationId	This is the unique LocationId for the location. This LocationId is used by the Quest Subsystem.
35-38	UInt32	NullValue4	Always 0x00000000 for all records.
39-40	Bool16	IsInterior	Exterior data (MapPItem) elements are FALSE (0x0000). Interior data (MapDItem) records are TRUE (stored as 0x0001).
41-44	UInt32	ExteriorLocationId	If the LocationRecordElementHeader describes interior data (MapDItem) and IsInterior is TRUE, this is the LocationRecordElementHeader for the exterior data (MapPItem) associated with this record. Otherwise, this value should be 0x0000. Since each DungeonInterior element must correspond to a LocationExterior element, this field's value must match a LocationExterior.LocationRecordElement.LocationId value.
45-70	UInt8[ 26 ]	NullValue5	Each element of this 28 byte field should be 0x00.
71-102	7-bit ASCII string	LocationName	Reports the NULL-terminated name of the location, but may not always exactly match the values in the MapNames record for the region. This value is used when displaying the name of a location when entering it. The fast travel map uses the MapNames record for display.
103-111	UInt8[ 9 ]	Unknown3	An unknown array of bytes, 9 bytes long.

IsExterior

IsExterior field enumeration

Value	Description
0x0000	The LocationRecordElementHeader describes dungeon interior data.
0x8000	The LocationRecordElementHeader describes location exterior data.

After the LocationRecordElementHeader, data specific to the record type (MapPItem or MapDItem) follows.

Location Exterior Data Record (MapPItem)

Each MapPItem record begins with a list of UInt32 values with MapNames.LocationCount elements. This is a list of offsets to the LocationExterior structures for each location. These values are relative to the end of the list, so adding (LocationCount * 4) to the offset locates the actual record. One offset may be greater than a subsequent one; no data order is presumed.

At each offset indicated, a LocationExterior structure is present, which includes all fields from the LocationRecordElement and some data of its own.

LocationExterior coarse structure

LocationRecordElement
BuildingListHeader
*BuildingData
ExteriorData

BuildingListHeader

BuildingListHeader structure

Offset	Type	Name	Description
0-1	UInt16	BuildingCount	This is the count of BuildingData structures which immediately follow this header, as a contiguous list. This field must be less-than-or-equal-to 0x7fff.
2-6	UInt8[ 5 ]	Unknown1	Unknown Purpose.

BuildingData

Immediately following the above header, is a contiguous list of BuildingData structures. Each BuildingData is 26 bytes long. BuildingData structures are associated with buildings within a settlement, such as a tavern.

BuildingData structure

Offset	Type	Name	Description
0-1	UInt16	NameSeed	This field is used as a seed value for generating the building's name.
2-9	UInt64	NullValue1	Should always be 0x0000000000000000.
10-17	UInt64	NullValue2	Should always be 0x0000000000000000.
18-19	UInt16	FactionId	This is the FactionId which should be associated with this building, or 0x0000 if no faction should be associated with this building. Valid values for this field are defined by the FACTION.TXT file.
20-21	Int16	Sector	This value seems to generally increase with each building. Changing this number at all crashes the game when the location is loaded. Always non-zero and ranges from 4 to 2329.
22-23	UInt16	LocationId	The value for this field should always be the same as the LocationRecordElementHeader.LocationId field.
24	UInt8	BuildingType	This indicates the type of the building. Valid values are defined in the Building Type Code enumeration.
25	UInt8	Quality	This specifies the quality of the building, always non-zero and ranges from 1 to 0x14 (20). Divide by 4 to rate on the "rusty-relics…" through "incense burning…" scale.

ExteriorData

ExteriorData structure

Offset	Type	Name	Description
0-31	7-bit ASCII string	Name	Appears to be another name for the location, but changing the value has no visible effect on the game.
32-35	Int32	MapId	Since each LocationExterior value must be described by a MapTable value, this field must correspond to a MapTable.LocationId value. The first 20 bits of this field matches the first 20 bits of a MapTable.MapId value; Simply match ( LocationExterior.ExteriorData.MapId & 0x000fffff ) with ( MapTable.MapId & 0x000fffff ).
36-39	UInt32	Unknown1	Unknown Purpose.
40	UInt8	Width	The width of the exterior data. This value may not be 0, and must be less-than-or-equal-to 8.
41	UInt8	Height	The height of the exterior data. This value may not be 0, and must be less-than-or-equal-to 8.
42-48	UInt8[ 7 ]	Unknown2	Unknown Purpose.
49-112	UInt8[ 64 ]	BlockIndex	Only the first Width * Height elements will have any meaning. See decoding instructions below.
113-176	UInt8[ 64 ]	BlockNumber	Only the first Width * Height elements will have any meaning. See decoding instructions below.
177-240	UInt8[ 64 ]	BlockCharacter	Only the first Width * Height elements will have any meaning. See decoding instructions below.
241-274	UInt8[ 34 ]	Unknown3	Unknown Purpose.
275-282	UInt64	NullValue1	Always 0x0000000000000000.
283	UInt8	NullValue2	Always 0x00.
284-371	UInt32[ 22 ]	Unknown4	Unknown Purpose.
372-411	UInt8[ 40 ]	NullValue3	Each element is always 0x00.
412-415	UInt32	Unknown5	Unknown Purpose.

Interpreting the Block Data arrays

The BlockIndex, BlockNumber, and BlockCharacter arrays all have a fixed size of 64 elements, but only the first Width * Height elements are used; the remainder are ignored. All 64 elements must be read just the same. These values are used to load the appropriate records from the BLOCKS.BSA file, which contains the automap data and are in turn used to load the appropriate meshes and models from ARCH3D.BSA to actually display the scene.

When accessing the block arrays, they should be synchronized. This is to say BlockIndex[ 5 ] should refer to the same Block record as BlockCharacter[ 5 ] and BlockNumber[ 5 ]. If one adds, removes, or reorders any array then one must reorder both of the other arrays to keep them synchronized.

The arrays are stored in west-to-east, south-to-north order. This means index 0 refers to the southwest corner of the location, and index ( Width * Height ) refers to the northeast corner of the location. Locations are not required to be squares (Width is not required to equal Height).

The details of the logic are described in Block Record Indexes.

Dungeon Interior Data Record (MapDItem)

Each MapDItem record begins with an UInt32 count (DungeonCount) of DungeonInterior elements contained within the record.

Dungeon Offset Section

Immediately following the DungeonCount field is a contiguous list of DungeonOffset values. Each value is 8 bytes long. The elements are not required to be in any particular order; That is to say the first element's offset could be higher than the second element's offset.

DungeonOffset structure

Offset	Type	Name	Description
0-3	UInt32	Offset	These offsets refer to the DungeonInterior elements of the record, and all offsets are relative to the end of the offset list.
4-5	Bool16	IsDungeon	This value is TRUE (stored as 0x0001) for all elements.
6-7	UInt16	ExteriorLocationId	Since each DungeonInterior element must correspond to a LocationExterior element, this field's value must match a LocationExterior.LocationRecordElement.LocationId value.

Dungeon Record Data

Each DungeonOffset.Offset refers to a DungeonInterior element. This is also a composite structure, similar to the LocationExterior structure.

DungeonInterior coarse structure

LocationRecordElement
DungeonHeader
+DungeonBlock
?Padding

DungeonHeader

Immediately following the LocationRecordElement structure is a DungeonHeader structure.

DungeonHeader structure

Offset	Type	Name	Description
0-1	UInt16	NullValue1	0x0000
2-5	UInt32	Unknown1	Unknown Purpose.
6-9	UInt32	Unknown2	Unknown Purpose.
10-11	UInt16	BlockCount	This is the count of the DungeonBlock elements in the contiguous list which follows. This value must be greater than 0 and less-than-or-equal-to 32.
12-16	UInt8[ 5 ]	Unknown3	Unknown Purpose.

Immediately following the DungeonHeader is a contiguous list of DungeonBlock structures, each 4 bytes long. There are BlockCount elements in this list.

DungeonBlock Element

Each DungeonInterior structure contains a contiguous list of DungeonBlock structures. There are exactly DungeonHeader.BlockCount elements in this list.

DungeonBlock structure

Offset	Type	Name	Description
0	UInt8	X	The X coordinate of the block.
1	UInt8	Z	The Z coordinate of the block.
2-3	UInt16	BlockNumberStartIndex	This is a concatenation of the BlockIndex and BlockNumber values. Decoding instructions follow.

The X and Z fields indicate how the blocks should be arranged in a two-dimensional grid. Dungeons are not required to be uniform such as squares or rectangles. They can contain empty spaces, or have spurs.

Ex: Privateer's Hold
           B0000012          
 B0000009 @S0000999  B0000003
           B0000006          

Ex: Mantellan Crux
 S0000005  S0000006                                        
           S0000004  S0000003  S0000002  S0000001 @S0000000

Decoding BlockNumberStartIndex

bits	Type	Name	Description
0-9	UInt16	BlockNumber	This value is used for decoding the string name of the RDB record from BLOCKS.BSA. As of the current patch, bits 8-9 are only necessary for Privateer's Hold (999); all other blocks require only bits 0-7.
10	Bool	IsStartingBlock	This bit is set (1) if this block is the "entrance" block. This is the block where the player starts when entering a dungeon. This bit is reset (0) otherwise. All DungeonInterior records must have one and only one DungeonBlock element with this bit set (1).
11-15	UInt8	BlockIndex	This value is used for decoding the string name of the RDB record from BLOCKS.BSA. Valid values are described in Block Record Indexes.

Padding

Immediately following the last DungeonBlock element are ( 128 - ( BlockCount * 4 ) ) bytes of padding. These values are simply padding and can be ignored. This gives each Dungeon a maximum of 32 DungeonBlock elements.