[mkgmap-dev] additional arcs patch

Thu Feb 20 21:20:53 GMT 2014

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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