Mapping database

[lundavra]

Am I right in thinking that the mapping databases used by most SatNav systems in the UK cannot distinguish between different types of single-carriageway (or perhaps even single-track) roads?

I get the distinct impression that they are categorised as single-carriageway, possibly dual-carriageway and motorway. This is the only way that I can explain the crazy routes that you get offered when away from the motorway network. On Anglesey last week I came up to the junction at SH 47224 72365 from the North West, heading for the B4419 to Newborough. I kept being told to the turn right which made no sense at all. I realised afterwards that it wanted me to take the back lane (unclassified) that cuts the corner off. This happens quite frequently and there seems to be no difference between shortest and fastest once off the motorway network.

This is with a Garmin Nuvi, the StreetPilot III was the same and I think the Road Angel has done similar.

MB

[Oldboy]

The Mapping Data classifies roads in up to 9, or 15, different categories. I can't remember which.

It's then up to the Navigation Software as to how many of these types are actually used. It requires a lot more programming to use all the types. So they take the easier option.
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Richard

TT 910 V7.903: Europe Map v1045
TT Via 135 App 12.075: Europe Map v1120

[Darren]

Indeed it's very much more detailed than you suppose with a great many classifications.

The problems arise when vendors compress the map data to fit onto their devices. At this stage they can choose to omit certain information and may reduce the categorisation levels as well as other data to fit a chosen format.
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Darren Griffin

[alix776]

there is a problem which is uk specificin that many unclassified roads have a 60mph speed limit then the navigation program may read this as a main road so uses it as a fastest road this could be why you seam to get "crazy" routes. always set the satnav unit to fastest
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currently using aponia truck navigation on windows phone. Good bye IOS don't let the door hit you on the way out .

Oh the joys of being a courier.
device Lumia 950 xl

[robertn]

All this data has errors, so the device manufacturers omit it because the more data you have, to more errors you have. At some point, there are so many errors the data becomes worse than useless.

Even if the data were error free, the algorythms to use it become more complex, more error prone, and more expensive to verify. Then the users want more control of the algorythms, so you have more options, more software cost, more complex manuals, more difficult useability design, and it's slower to implement so more time to market.
So then the manufacturer would go bust, because their fanatistic product would be delivered over priced, late, and unuseable, so noone would buy it.

The cost of all this extra bling does not translate to sales volume and profit, so it is not done, as most people in business don't want to go bust - fair enuf I say. One day, through iterative product cycle, you will get it, but this is an industry thats still a baby - you need to learn to walk before you can run.

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