[mkgmap-dev] additional arcs patch

Sun Feb 23 11:15:42 GMT 2014

I have compared results from the branch and the trunk.

I have to revert my suspicion: distances are equal.

I see some differences in routing so that it seems that larger roads are 
much more prefered in trunk than in branch. I'll have to check if that's 
good or bad :-)

WanMil

> Ignore the Google result.
>
> I am quite sure that there is a difference between the high-prec-coords
> branch and the trunk. I need to recompile the map with the trunk to
> confirm this.
>
> WanMil
>
>> Please, forgive my 2 cents on this:
>>
>> Depending on which projection each system is using, distance calculation
>> may (and usually) differ by that much and maybe more.  As far as I know,
>> Google uses a Mercator-like projection on a spherical Earth model, which
>> is not correct since Google coordinates refer to the WGS-84 ellipsoid.
>> So you can expect differences, greater with higher latitudes.
>>
>> So don't use Google as an accurate reference.
>>
>> all the best,
>>
>> Paulo
>>
>>
>> 2014-02-20 17:23 GMT-03:00 WanMil <wmgcnfg at web.de
>> <mailto:wmgcnfg at web.de>>:
>>
>>     Hi Gerd,
>>
>>     which difference do you expect regarding the indirect links? I want
>>     to get an idea what I should check on my device.
>>
>>     I have compiled a map using the patch and it seems that distances
>>     are slightly underestimated.
>>     One example: The distance between Hambug, An der Alster and Munich,
>>     Maximiliansplatz:
>>     MapSource: 776km
>>     Google Maps: 788km
>>     Both use the same route.
>>
>>     I didn't notice it before.
>>
>>     WanMil
>>
>>         Hi all,
>>
>>         attached is a patch for r3065 in the high-prec-coord branch.
>>
>>         It should improve long distance routing, as it adds additional
>>         arcs from minor roads to major roads (so called indirect links).
>>         Maybe the improvement is only seen on the device.
>>
>>         It would be great to hear some test results (good or bad),
>>         compared to trunk r3057 and compared to r3065.
>>
>>         A compiled binary is here:
>>         |http://files.mkgmap.org.uk/__download/179/mkgmap.jar
>>         <http://files.mkgmap.org.uk/download/179/mkgmap.jar>
>>
>>         |Gerd
>>
>>
>>
>>
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