Tomtom Navigator POI.DAT File description

This page is about a description of the file POI.dat used by Tomtom Navigator (v2, v3 and v5) to store theirs POIs.

Important : POIs from Tomtom Navigator are copyrighted and you CAN'T used the informations in this page to exploit-modify-diffuse natives POIs or do anything that Tomtom licence prohibit.
However, it seems that licence permit to replace native POI.DAT with yout own file, based on private or free datas.

Note that if you think that this page is written in a strange english language, don't hesitate to correct it

I wrote a perl software (extract_ttpoi.pl) that implement these informations.

General structure

• a longitude
• a latitude
• a description. With Tomtom 5 come optional Phone Number. This field is include in the description, using ">" as a separator (ex : "My favorite POI>+33-1-2345789")

• a category ID : an uniq integer thar refer to the category
• a category descritpion : un simple string, depending og the language. This description is different in each language ddl file

The following description consider an integer as 4 bytes. Also, the file is encoded as little-endian

The POI.DAT file is composed of several section :

Bytes	Description
4 bytes	N : the number of categories in the file as an integer
N*4 bytes	a table of N integer that contains the category ID (see Annexe A)
(N+1)*4 bytes	a table of N integer that contains the offset in this file of the begining of the POIs for the category. There is one more integer because of the offset of the end of block of the last category. So the the offsets of the category of index M can be computed as (C code) : first offset = table[M] last offset = table[M+1] - 1
? bytes	N blocks of ? bytes for the POIs themself

We are now able to identify each block of data that contains POIs. POIs are compressed, but not encrypted. However, the originals POIs are copyright, as explain the licence of the product. So please refer to this licence before exploit the datas.

The reason why POIs are compressed is to save memory. There is also a special encoding that let Tomtom to fast search a POI according to the GPS position.
The block of data is composed of records. Each record will be describe after. New Records could be added by Tomtom with futures release (ex : records 0x0C in Tomtom Navigator 5).

There is 2 kinds of record :

• Area Record : they divides the map in little squares. This kind of record contains other records (area record or POIs records. For now, there is a uniq Area Record type (0x01)
• POIs Record : they contain a POI, as describe bellow. There is multiple methods used by Tomtom to compress (or not) the description. There is as many POI record types as encoding method

Aera Records

Here is an exemple of Record structure :

 Record 01                  (compelete map)    1835757 km²
  Record 01                 (level 1)           931185 km²
   Record 01                (level 2)           629400 km²
    Record 01               (level 3)           440059 km²
     Record 01              (level 4)           305839 km²
      Record 01             (level 5)           262615 km²
       Record 01            (level 6)           191422 km²
        Record 01           (level 7)           167841 km²
         Record 01          (level 8)           112220 km²
          Record 01         (level 9)           101074 km²
           Record 01        (level 10)           97175 km²
            Record 12
            ...
            Record 12
           Record 01        (level 10)            3899 km²
            Record 12
            ...
            Record 12
          Record 01         (level 9)            11187 km²
           Record 01        (level 10)           10958 km²
            Record 12
            ...

This graph shows an example of map divisions :

POI Records

Record 01

Bytes	Description
1 byte = 0x01	The Record Type
4 bytes	N : the total size of this record (including the 21 bytes header)
4 bytes	Longitude 1 (in decimal degrees). This value has to be divide by 100000
4 bytes	Latitude 1 (in decimal degrees). This value has to be divide by 100000
4 bytes	Longitude 2 (in decimal degrees). This value has to be divide by 100000
4 bytes	Latitude 2 (in decimal degrees). This value has to be divide by 100000
N bytes	Block of datas containing other records

Record 02 & 15

Bytes	Description
1 byte = 0x02	The Record Type
4 bytes	N : the total size of this record (including the 02 bytes header)
4 bytes	Longitude (in decimal degrees). This value has to be divide by 100000
4 bytes	Latitude (in decimal degrees). This value has to be divide by 100000
N bytes	Clear text POI description

Record 04 & 20

Bytes	Description
1 byte = 0x04	The Record Type
3 bytes	Encoded Longitude
3 bytes	Encoded Latitude

Record 05 & 21

Bytes	Description
1 byte = 0x05 or 0x15	The Record Type
3 bytes	Encoded Longitude
3 bytes	Encoded Latitude
2 bytes	unsigned 16 bits numeric value (little endian)

Record 06 & 22

Bytes	Description
1 byte = 0x06	The Record Type
3 bytes	Encoded Longitude
3 bytes	Encoded Latitude
3 bytes	unsigned 24 bits numeric value (little endian)

Record 07 & 23

Bytes	Description
1 byte = 0x07	The Record Type
1 bytes	N : the size of this record, minus 8 (the size of the fixed part of the record)
3 bytes	Encoded Longitude
3 bytes	Encoded Latitude
N bytes	Clear text POI description

Record 08 & 24

Bytes	Description
1 byte = 0x08 or 0x18	The Record Type
1 bytes	N : the size of this record, minus 8 (the size of the fixed part of the record)
3 bytes	Encoded Longitude
3 bytes	Encoded Latitude
N bytes	encoded POI description

The compressed method is the following :

• if (next byte & 0x80) == 0
  The next 2 bytes can be decompressed in 3 letters, each letter encoded on 5 bits (1 + 3*5 = 2 bytes)
  These 5 bits (32 values) must be transposed in letter (see Annexe B for transposition table)

  ex : these 2 bytes (binary format) present 3 characters : 0AAAAABB BBBCCCCC

• if (next byte & 0x80) == 0x80
  The next byte encode one character, with a transcription of the first quartet (4 high bits) (see Annexe C for transposition table)
  The second quartet is remain unchange

Record 09 & 25

The Format is the following :

Bytes	Description
1 byte = 0x09 or 0x19	The Record Type
1 bytes	N : the size of this record, minus 8 (the size of the fixed part of the record)
3 bytes	Encoded Longitude
3 bytes	Encoded Latitude
N bytes	encoded POI description

The compressed method is the following :

Each character of the POI description consume a variable number a bits, using a transposition table (see Annexe D for the transposition table). This seems to be a b-tree (binary tree). The Build of this table is made using frenquence letters analyze, so that "a", "e", "i" comsume more bits than "Q", "X", "Z".

The block of data has to be used as a serie of bits. There is a special sequence of bit that have a special meaning (End of String).
The way the bits are arranged in the block is a little special : each byte must reverse the position of his bits as the following :
The byte (binary format) 0bABCDEFGH will be transform in 0bHGFEDCBA
So 0b10010010 will be transform in 0b01001001

Then, the data can be decoded, using the transpotion table.
For example

starting with the bytes : 0x68 0x78 0x3c 0xb2 0x01
This can be transform in binary : 01101000 01111000 00111100 10010010 00000001
and then revert                 : 00010110 00011110 00111100 01001101 10000000
and then, using b-tree table    : 00010 1100 0011 1100 0111 1000 1001 1011 (0000000)
and then                        : station

Record 10 & 26

The Format is the following :

Bytes	Description
1 byte = 0x0A or 0x1A	The Record Type
1 bytes	N : the size of this record, minus 8 (the size of the fixed part of the record)
3 bytes	Encoded Longitude
3 bytes	Encoded Latitude
N bytes	encoded POI description

The compressed method is the following :

Each pairs of 2 bytes (little endian encoding) can be decompressed in 3 character. The optional last byte give one character.
The characters can be obtained by calculate the modulus-40 three times on the 2 bytes, and 1 time on the 1 byte. This give 3 indexes on a transposition table :

  abcdefghijklmnopqrstuvwxyz0123456789 .-

if modulus is 0, this is consider as the end of string.

For example

starting with the bytes : 0x59 0x20, this give the value 0x2059 (8281)
get the modulus 1 : 8281 % 40 = 1           : A
get the modulus 2 : (8281/40) % 40 = 7      : G
get the modulus 3 : ((8281/40)/40) % 40 = 5 : E

Note : Thanks to "Didier71" for his work

Record 12 & 28

The Format is the following :

Bytes	Description
1 byte = 0x0C	The Record Type
1 bytes	N : the size of this record, minus 8 (the size of the fixed part of the record)
3 bytes	Encoded Longitude
3 bytes	Encoded Latitude
N bytes	encoded POI description

This Record is a new record from TomTom v5.

These records have 2 blocks of data

• Text Block that contain the POI description (alphabetic characters). These characters are coded on 5 bits
• Phone number (numeric characters). These characters are coded on 4 bits

Each block have a special 5-bit code that is an end of string. After this code, the 2nd block directly begin, until the special 4-bit code that is the end of the phone number.

The way the bits are arranged in the block is a little special : the coded string data have to be first reverse. Then, the group of 5 bits (and then 4 bits) have to be parse from the end of the reversed data, as the following :
The bytes (binary format) 0bABCDEFGH 0bIJKLMNOP 0bQRSTUVWX will be reversed in 0bQRSTUVWX 0bIJKLMNOP 0bABCDEFGH, and the the groups of 5-bits will be (QRST) UVWXI JKLMN OPABC DEFGH

Then, the data can be decoded, using the transpotion table, and the resulting clear text have to be reverse.

For example

starting with the bytes : 0x51 0x02 0x89 0x5c 0xd3 0x21 0x03
This can be transform in binary : 01010001 00000010 10001001 01011100 11010011 00100001 00000011
and the revert string           : 00000011 00100001 11010011 01011100 10001001 00000010 01010001
and then, using the tables      : 0000 0011 0010 0001 11010 01101 01110 01000 10010 00000 10010 10001
and then                        : "210" & "noitats
and then, using b-tree table    : Description:"station" & Phone Number:"012"

  For an Area Record of (-165.12345, 55.12345) - (-151.12345, 58.12345)  (Alaska)
  The POI Longitude is : 0x6C9785  that is 8755052 in decimal
     8755052 - 8000000 =    755052
      755052 - 8000000 =  -7244948
    -7244948 - 8000000 = -15244948   it's this value !!!

Annexe A : Category ID

Category ID	English	French
7367	Government Office	Bureau gouvernemental
9364	mountain Peak	Sommet montagneux
7369	Open Parking	Parking ouvert
7313	Parking Garage	Parking couvert
7311	Petrol Station	Station-essence
7380	Railway Station	Gare ferroviaire
7395	Rest Area	Aire de repos
7383	Airport	Aéroport
9910	Car Dealer	Concessionnaire automobile
7341	Casino	Casino
9906	Church	Eglise
7342	Cinema	Cinéma
7379	City Center	Centre-ville
9352	Company	Société
9367	Concert Hall	Salle de concerts
9363	Courthouse	Palais de justice
7319	Cultural Center	Centre culturel
7385	Exhibition Center	Centre des expositions
7352	Ferry Terminal	Terminal de car-ferry
7366	Frontier Crossing	Frontière
9911	Golf Course	Terrain de golf
7321	Hospital Polyclinic	Hôpital/clinique
7314	Hotel/Motel	Hôtel/motel
7376	Tourist Attraction	Site touristique
9935	mountain Pass	Col montagneux
7317	museum	Musée
9365	Opera	Opéra
7339	Place of Worship	Lieu de recueil
7324	Post Office	Bureau de poste
7312	Rent Car Facility	Centre de location de véhicules
9930	Rent Car Parking	Parking pour véhicules de location
7315	Restaurant	Restaurant
9361	shop	Magasin
7373	shopping Center	Centre commercial
7374	stadium	Stade
7318	Theatre	Théâtre
7316	Tourist Information Office	Syndicat d'initiative
9927	Zoo	Zoo
7320	sports Centre	Complexe sportif
7322	Police Station	Commissariat de police
7365	Embassy	Ambassade
7377	College University	Lycée/université
7397	Cash Dispenser	Billetterie
9357	Beach	Plage
9360	Ice Skating Ring	Patinoire
9369	Tennis Court	Court de tennis
9371	Water Sport	Centre de sports aquatiques
9373	Doctor	Docteur
9374	Dentist	Dentiste
9375	Veterinarian	Vétérinaire
9379	Nightlife	Activités nocturnes
9902	Amusement Park	Parc d'attractions
9913	Library	Bibliothèque
7310	Car Repair Facility	Réparations automobiles
7326	Pharmacy	Pharmacie
7337	scenic/Panoramic View	Vue panoramique
7338	swimming Pool	Piscine
7349	Winery	Cave à vins
7360	Camping Ground	Terrain de camping
9362	Park and Recreation Area	Parc et aire de jeux
9377	Convention Centre	Centre de conventions
9378	Leisure Centre	Centre de loisirs
9380	yacht Basi	Marina
9980		Code postal
9800		Légal/Mandataires
9801		Légal/Autre

Annexe B : Record 8 transposition table

5 bits value	Trasposition letter
00000	not used
00001	.
00010	<space>
00011	S
00100	a
00101	e
00110	r
00111	i
01000	o
01001	n
01010	s
01011	t
01100	l
01101	d
01110	c
01111	h
10000	u
10001	m
10010	g
10011	p
10100	b
10101	k
10110	f
10111	z
11000	v
11001	A
11010	C
11011	B
11100	M
11101	P
11110	G
11111	-

Annexe C : Record 8 transposition table

quartet source	quartet destination
1000	0010
1001	0011
1010	0100
1011	0101
1100	0110
1101	0111
1110	1110
1111	1111

Annexe D : Record 9 transposition table

Annexe F : Record 12 transposition table (numeric table)