[mkgmap-dev] additional arcs patch

Thu Feb 20 20:41:22 GMT 2014

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>:

> 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
>>
>> |Gerd
>>
>>
>>
>>
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>>
>>
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