OSM Map On Magellan/Format/raimadb

Raima DB

The Magellan Map file uses a Raima DB Version 3.0 for storing text informations. This tries not to be a complete specification on the data base binary format. It shall only list, what is needed to know about it, to generate a compatible map.

The Raima Db conatains several tables, each stored within a single file and a dictionary file (db00.dbd) When the database is used in compression mode, there also exists one file per table, containing compression data/indexes.

db00.dbd

The dictionary lists all files, tables and fields belonging to the db. The file starts with a 22 bytes header, followed by the file table, then the list of tables and at least all fields within the tables.

The PageSize is used in the table files. The data in the tables is organized in pages. This values specifies how big they are.

File Descriptor

Each file belonging to the database is described in the list of file descriptor. Each file descriptor is 60 bytes long. The first 49 bytes are reserved for the file name, the rest contains some flags and parameters belonging to the file.

Each record inside a table must start on an even byte position. When the record length is odd the aligned record length is the real record length plus 1.

Here is the file descriptor for a compression table:

Compression data Files have the file name extension as the corresponding file and also the name is nearly the same. The difference is a trailing c in the name of the compression data file.

Data File 00cn.dat => Compression data File 00cnc.dat

Table Descriptor

Next follows the list of tables. Each Entry in this list is 12 bytes long. The compression tables are not listed here only the tables containing data.

List of Fields

Each table may have multiple fields per row. All fields of all tables are listed next. In the table descriptor there is an index (Index of first Field in Field list) pointing to the first field belonging to a table. Following types of fields are used within magellan data base files:

The file ends with the list of table names and field names, each seperated by a Carriage return ('\n').

Each row in a table has 6 starting bytes containing table and row number.

Tables

The first table in the Database is a zip Code table and a City name table. These two tables are typically empty.

This is followed by three tables per group containing names of elements in the layer files and linkage informations. ([GroupNr.] is a placeholder for the numerical number of the group, the three tables belong to.

This table can contain several texts/names in a single row. When this is the case, all texts are seperated by a 0x00 byte. It is also possible, that a text exceeds a single line. In this case the last byte of the String is not a 0x00 but any character. This is used to tell the interpreter, that the text is continued in the next row. In all other cases the last byte in the array must always be a 0x00.

This table links between the elements in layer files.

• 'NAME_REF' references a text entry in the Text Table. It is calculated by NAME_REF = (Offset of the text in the row) << 24 + (row number)
• 'CELL_NUM' is the number of the cell in the layer file.
• 'N_IN_C' is the number of the referenced element within the cell
• 'OBJ_TYPE' is at the end nothing else than the layer itself.

(All types listed in the table description are field types from the chapter before)

This table can remain empty. (Purpose is unclear)

Example

Here is an example of an db00.dbd file for a table with a single group. All files in the table are compressed. Following files are belonging to the database:

• 00cn.dat City Name References
• 00cnc.dat Compression data for 00cn.dat
• 00z.dat Zip code table
• 00zc.dat Corresponding Compression data
• 00gr0.aux Text Table
• 00gr0c.aux Compression data
• 00gr0.ext Link table
• 00gr0c.ext Compression data
• 00gr0.clp CLP Table
• 00gr0c.clp Compression data
• db00.dbd Database dictionary