Techdirt recently wrote about the growing number of websites that have been dumping Google maps and re OpenStreetMap (OSM) in place. But this is only part of the digital mapping industry, more and more important, the other is for use with satellite navigation systems in the car. So the obvious question is: how OpenStreetMap doing here?

seems that GPS manufacturer TomTom has just given an answer (found via Slashdot):

Despite recent positive studies have highlighted some of the major disadvantages of open source mapping, especially in security, accuracy and reliability. In one case, a main board open source was compared with a business card, TomTom, and showed that

aa coverage third residential road less and 16% less than the base map attributes such as street names.

Worse, the mixture of pedestrians and car geometry map, and included "a large number of fields and forest roads" classified road.

TomTom

As explained, this is a bad thing:

Many drivers rely heavily on satellite navigation for precise instructions, and mapping errors can be extremely dangerous, especially in the case of one-way streets .

If not received the message, TomTom concludes:

open source application definitely has its advantages and can be extremely useful, especially for pedestrians and in the center of the town or city. The way the cards incorporate input from a wide community of collaborators can result in impressive international coverage, while reducing production costs. However, when it comes to car quality maps, open source has serious limitations, below levels of accuracy and reliability needed for safe navigation.



Unfortunately, TomTom does not share their sources of these figures, but Carlo Daffara sent us to this investigation since December 2011, which provides a more detailed analysis on the relative merits TomTom OpenStreetMap and Germany. This is what I found:
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