CNET Australia hitched a ride with Navteq's team of analysts to see how they produce maps — used in GPS devices from Mio, Navman and Navigon — covering our big brown land.
Call that a GPS? This is a GPS!
The cars that Navteq use for mapping are fitted with a highly sensitive roof-mounted GPS antenna; it's the small white dome at the rear of the roof-mounted sleigh. The antenna needs to be locked on to at least seven satellites to function — three is the minimum needed for any GPS unit to determine your location. As such, this antenna is accurate down to about 50 centimetres, which is several times better than those on portable GPS navigation devices, which can determine your position to about 10 metres.
In front of the GPS antenna is a six camera array housed in a perspex bubble, which takes geotagged images continuously as the car goes about its business. Once back in the office, Navteq's analysts can review footage to check for anything they may have missed or to sort out points of contention.
What? No space for my golf clubs?
Taking pride of place in the boot of Navteq's Ford Escape is the hardware which logs GPS data, stores images from the car's six cameras, as well as being a repository for the analyst's notes.
An analyst, using the attached tablet, as well as the optional microphone, notes down information relevant to the roads travelled. This info includes street numbers at intersections, traffic restrictions, speed limits, traffic lights, and important buildings and institutions. All this data is brought back to base to be encoded, with points of contention sorted out by reviewing footage shot by the car's camera.
According to Navteq, for any one day that an analyst spends on the road, they're likely to spend two in the office encoding, verifying and adding information gleaned from their travels.
With almost a million kilometres of roads in Australia both Navteq and the incumbent Whereis have been unable to travel it all. As such, they rely on government or other sources for their base mapping data.
For Navteq, the base map is supplied by PSMA, a public company owned by state and federal governments, which aggregates mapping information from all levels of Australian government. The data from PSMA contains about 15 attributes, including street names, geometry, local government boundaries and the centre line of roads.
As a Navteq mapping vehicle travels, a point is added to the mapping trace every few metres and is laid over the base map. The mapping trace above is for a spaghetti junction in Chicago.
What the heck is that?
Traffic lights, no right turns, one way streets — they're all par for the course when you're mapping any country in the world. But it seems as though every place has something unique to throw into the mix and Australia's contribution is Melbourne's famous — or infamous, depending on whether you're a local or not — hook turn.
Mapping cars must stop frequently, especially in built-up areas where there is a high concentration of intersections, different traffic restrictions and points of interest. Riding in a mapping car requires patience, as the speed is often just above walking pace. Navteq Australia's previous fleet of cars didn't have the prominent livery seen here and caused one or two anxious moments for on-lookers worried about a suspicious looking car, which stopped frequently and had a dome on the top.