[mkgmap-dev] Routing across multiple tiles

Thu Jul 30 22:25:19 BST 2009

Ralf Kleineisel wrote:
> On 07/28/2009 08:04 PM, MarkS wrote:
> 
>> However, if I route across multiple tiles then it always fails. 
>> Mapsource just spends ages and then draws a straight line whilst my 
>> garmin counts to 100% and says their was a calculation error.
> 
> It does work for me. I routed successfully through half of Germany and the
> Netherlands with a map made with r1065. Used Geofabrik Europe data and
> mkgmap-splitter.
> 
> What are the command line options you used?

These are the command lines I just tried with.

java -Xmx1200m -enableassertions -jar ../splitter/splitter.jar
--max-nodes=1500000 ../great_britain.osm

java -Xmx1200m -jar ../mkgmap-r1099/mkgmap.jar --latin1
--remove-short-arcs --lower-case --preserve-element-order
--location-autofill=1 --gmapsupp --route --net --tdbfile -c template.args

They seem to improve the situation slightly (it will sometimes route
across a whole tile). However, equally it fails to route sometimes even
when the start and end are within the same time. For example in the
attached gdb file it fails to route from "Cornwall" to "Wales" (same tile).

A number of other routes (eg. "Bramley" to "Hol", "Sherfield" to "Hol")
also fail to calculate, whereas "M4" to "A1" calculates fine and covers
the same sort of tiles.

All the routes have been tried in Mapsource (v.6.15.6), altough I've had
similar behaviour in 6.13.7.

I've also done a bit of experimenting:

- My routing preference has been set at the mid point. If I move the
slider two notches up towards prefering highways then I don't have a
problem. suggesting that it might be complexity of the route.
- In a test (on a separate machine) against a Garmin map, the gamin maps
had no problem with the routing.
- Using splitter with less max-nodes (and therefore more tiles) makes
the situation worse.

I wonder if it is something to do with minor roads (and inter-tile
connections). Maybe they get a higher class on mkgmap than on the garmin
maps. This allows more complex routes, which eventually overloads the
routing calculation and it fails.

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