[Routing] Binary file format

[Marcus Wolschon]

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Hello Adiran!

Adrian Stabiszewski schrieb:
> The first thing which bothers me for some time now, is that on mobile
> devices it will be quite impossible to parse several hundreds MB of XML data
> in reasonable time. Also you won't have an SQL database running that you can
> use for querying data.

Actually there are quite some in-memory-databases for mobile
devices that are very fast. I found parsing the xml broken up into
"tiles" to be much faster then any database. But then a binary-format
could probably save a lot of flash/ram-space and io-bandwidth.

> The other thing that is bothering me is that the data in OSM is very good
> for rendering, but it is suboptimal for routing. The way ways are connected
> with each other is ok for rendering, but it is not good for routing. The
> problem I see is that ways are not connected with each other using junction
> nodes. With junction nodes it would be possible to calculate the distance
> between those nodes while creating the binary file and thus speed up the
> calculation of the route.

Yes, a binary-format would be a great thing to have. I don't quite see
what you mean with junction-node but maybe you could do a first outline
of a format or a list of reqirements that you see for it.
We could start from there.

> During my tests
> travelling-salesman couldn't even find a route between two streets which
> were only several hundreds meters apart...

That is strange. I'm regularly routing between streets inside major
cities with long motorways and villages between the cities.

Do you have some repeatable test-case that I can investigate?

Marcus
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