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TomTom ITN — Plain-text Route for GO/Start: Micro-degrees, 100-stop Limit and Legacy Status

2026-05-249 min read
TomTomITNitinerarynavigationASCIIwaypointlegacy
Export formats: TOMTOM-ITN

ITN is a plain ASCII route file for TomTom GO, Start, Via, and Via Live navigators of the 2005–2015 era. Extension .itn, encoding usually UTF-8 without BOM (older devices — CP1252), inside — a line-per-waypoint list in the format <longitude>,<latitude>,<description>,<type>. Coordinates are stored in micro-degrees — an integer equal to degrees × 100000, with no decimal point: 523616 means 5.23616° east longitude. The waypoint type is a single-digit code: 0 an ordinary passing point, 1 a via-point (the route must pass through it), 2 start, 4 end. The limit is around 100 stops; beyond that, firmware on older GO 720 / Start 25 / Via 130 either truncates the file or refuses to load it. On osm2cdr.ru the ITN export is a thin wrapper around routing-node dumps from PostGIS: each route point becomes one line of a text file, ready to be loaded via TomTom MyDrive Connect or copied to the device manually.

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History: TomTom GO and the Birth of ITN

TomTom International was founded in Amsterdam in 1991 as a PDA software developer. In 2002 the company assembled its first standalone navigation device — Navigator on a Compaq iPaq base, and in March 2004 the TomTom GO 300 shipped: a compact self-contained box with a color touchscreen, a GPS receiver, and an SD card with Tele Atlas maps. The GO 300 became the first mass-market in-car GPS navigator; by 2007 TomTom had sold over 12 million devices and dominated the European market alongside Garmin Nuvi.

The device needed a format for importing user routes. The TomTom team didn't invent XML or a binary container — they picked a maximally simple plain-text format that the user could open in Notepad and edit by hand, and a partner developer (tour operator, logistics company, automobile club) could generate with a one-line shell script. Thus the ITN appeared — Itinerary file, describing an ordered sequence of waypoints for the route. Standard workflow of those years: the user prepared a tour in TomTom Home (a Windows/Mac desktop app), the app wrote .itn to the itn/ directory on the SD card, and the device picked up the route on next boot.

The ITN peak was 2005–2012 — the hardware-GPS era before smartphones. By 2013 TomTom released the Via Live line with 4G connectivity, on top of ITN a new .ov2 format was added for POI overlay (points of interest outside the route), and ITN itself gradually got displaced by the cloud routing engine in MyDrive. Since 2018 all new TomTom GO Premium / Discover devices route through MyDrive cloud routing, and ITN remained a legacy mechanism for older devices — but firmware still supports it "for compatibility," and ITN stays in active use among owners of old GO 950, Via 130, and logistics companies that don't want to swap their dialed-in 2010s stack.

Inside ITN: Text Structure

ITN is plain text, one line per waypoint, comma-separated with no escaping. Minimal example: Berlin Mitte → Brandenburger Tor → Reichstag → Museumsinsel:

1338100,52520000,Start Berlin Mitte,2
1338020,52516280,Brandenburger Tor,1
1337760,52518810,Reichstag,1
1340510,52520830,Museumsinsel,1
1341330,52520830,End,4

Longitude (first number). Longitude in micro-degrees — an integer equal to degrees × 100000, with no decimal point and no sign for positive values. East longitude positive, west negative: 1338100 = 13.38100° E (central Berlin), -740060 = −7.40060° = 74.0060° W (Manhattan). Note: some early TomTom docs cite a 100000 multiplier (5 fraction digits), and that's exactly what real GO 720 and later firmwares use. Precision ≈ 1.1 m at the equator — plenty for automotive navigation.

Latitude (second number). Latitude in the same micro-degrees. North positive, south negative: 52520000 = 52.52000° N (Berlin), -33867500 = −33.86750° = 33.86750° S (Sydney).

Description (third field). Text label for the point. Allowed characters — 7-bit ASCII on old GO 300 / 510, UTF-8 on newer Via / GO Premium (still with a length limit, typically 60 chars on the display). Commas and newlines inside the description are forbidden — replaced by a space or dash. Cyrillic wasn't supported on GO 720; write "Brandenburger Tor", not the Cyrillic name.

Type (fourth number). Single-digit code: - 0 — ordinary passing waypoint, the device passes near but isn't required to enter - 1 — via-point, the route must pass through this coordinate - 2 — start - 4 — destination (end)

Type 3 is reserved and unused in modern firmware. There must be exactly one 2 and exactly one 4 in the file; everything else is 0 or 1. If 2 is missing — the device uses its current GPS position as start.

The limit is around 100 points per file. GO 720 and Start 25 accept up to 100, GO 950 LIVE and later Via — up to 150–200, the new GO Discover — formally unlimited, but staying under 100 is still recommended for backwards compatibility. Large tours get split into multiple ITNs and switched manually from the Itinerary menu.

Use Cases

Last-mile logistics. A courier company plans a daily driver route: 30–50 delivery stops in one city, 60–80 km tour. The ITN file gets generated overnight from the ERP system (one line per address), loaded to TomTom GO 6200 in the morning via MyDrive Connect, the driver hops in the van and follows the preloaded route. Advantage over cloud routing: works without internet (matters in suburbs with bad coverage), no monthly subscription, the format is so simple it's generated by a bash script with no SDK needed.

50-stop tourist itinerary. A guide prepares a "Baltics in a week" bus tour — Tallinn, Tartu, Riga, Jurmala, Sigulda, Trakai, Vilnius with intermediate stops at castles, museums, village inn lunches. Each stop is a separate via-point with a description. The ITN is uploaded to the company cloud in advance; the tour-bus driver with a TomTom Via 53 loads the file before departure, and the device routes through all 50 stops in the correct order without manual address entry on the road.

Workflow in OSM2CDR

Our ITN exporter is the simplest of 136 exporters in the service: a single tomtom_itn_exporter.py file of ~120 lines, a BaseExporter subclass with ExporterType.LAYERS. Pipeline:

  1. Get waypoints. Input is the routing_waypoints layer — route points in traversal order, with name (description) and wp_type (0/1/2/4) attributes. Points come either from OSM routing via OSRM, or are passed by the user directly through the API.
  2. Convert to micro-degrees. Each lon, lat coordinate (WGS84, decimal degrees) is multiplied by 100000 and rounded to an integer: int(round(lon * 100000)). Signs preserved for western hemisphere and southern latitudes.
  3. Sanitize description. Strip commas and newlines, truncate to 60 chars. If transliterate=true is set — Cyrillic goes through unidecode for old-GO compatibility.
  4. Write the text file. Plain open(path, 'w', encoding='utf-8') plus a for wp in waypoints: f.write(...) loop. No ZIP, no header, no footer.
  5. Validate. Before closing the file we check for exactly one 2 and one 4; if start or end is missing, they're auto-filled from the first/last waypoint.

Endpoint: POST /api/render?format=tomtom-itn accepts bbox, waypoints[] (array of {lat, lon, name, type}), or route_id (a pre-computed route from the routing engine). Output is tens of bytes per waypoint; a typical 30-stop file is about 1.5 KB. Loading to the device: connect TomTom via USB, open the device drive in your file explorer, copy .itn into the itn/ directory (on GO 720) or Internal Memory/itn/ (on Via / GO Premium). After reboot the device shows the route in the "Itinerary planning" menu.

ITN vs OV2 vs GPX

ITN was useful for routes — an ordered sequence of points the navigator must traverse in given order. That's its specialty: one file = one tour. ITN isn't meant for POI overlay (showing the user every restaurant in town) — you'd need a separate route file per restaurant, which is nonsensical.

OV2 appeared in 2007 as a binary POI overlay format: millions of points of interest in a single file, with types, indexing for fast search, icons. OV2 displaced ITN in the POI niche: speed cameras, gas stations, hotels, restaurants. ITN stayed for routes only.

GPX is the XML standard of the entire GPS industry since 2002. Modern TomTom GO Premium / Discover natively understand GPX routes, and for new devices GPX is preferable: universal format, opens in Garmin BaseCamp, Komoot, Strava. ITN survives only where you need compatibility with 2005–2015 firmware or where an ITN generator is already wired into a company's legacy ERP.

Garmin GPI is the functional equivalent of OV2 in the Garmin world; it doesn't overlap with ITN.

When to pick ITN: a fleet of older TomTom GO 720 / Start 25 / Via 130, a simple workflow without an SDK, route generation from an ERP script. When not to: new devices (use GPX), multi-platform tourist workflows (also GPX), POI overlays (OV2 or GPI).

Conclusion

ITN is a long-lived TomTom text format: 20 years in service, firmware still supports it, a generator can be written in one evening. Strengths — extreme simplicity (one line = one waypoint), full readability in Notepad, zero-overhead pipeline with no dependencies. Weaknesses — legacy status, ~100-point limit, narrow route-only niche, no POI. On osm2cdr.ru ITN lives as a niche export for logistics companies running TomTom GO 6200 fleets and tour operators on Via 53. If one of those use cases is yours — try the export now.

Create an ITN route for TomTom in 30 seconds

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Sources

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