[mkgmap-dev] [PATCH v1] - Reduce number of Table A entries required

Tue Sep 22 00:49:17 BST 2009

Reduce number of Table A entries.

    Previously, Table A entries were unique for each combination of start node,
    end node and RoadDef. But no information from the start and end nodes goes
    into Table A so we can ignore the start and end nodes and all roads
    within a given routing centre that use the same RoadDef can now share a
    Table A entry. This reduces the number of entries required which makes
    the .img files smaller and, hopefully, also improves the routing because
    routing centres can now cover a larger area.

I have tested this with mapsource and on a Nuvi and it appears to work
OK but it really needs more testing before it could be considered for
committing.

So, all feedback is welcome regarding the effect this patch has on
routing performance. With the patch, the routing changed and I thought
it was more sensible but perhaps that's just wishful thinking.

My GB map shrunk from 180 to 174 Mb with this patch.

The Nuvi calculated a route from Lands End to Thurso (800+ miles and quite a few tiles) in no more than 10 seconds.

Cheers,

Mark
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