[mkgmap-dev] help needed

Thu Jul 31 17:41:18 BST 2014

Hi Andrzej,

thanks for the hints, I'll have a look at them tomorrow. I think
"Spherical versus ellipsoidal model" as a reason is unlikely, the difference
should
be < 1 %, not ~50%
Today I looked at various webpages which calculate the distance between
two points, e.g. airports. It is quite funny how different the results are,
probably because some are using R=6371 km and others 6378.135 m or
values between.

Gerd

popej wrote
> Hi Gerd,
> 
> I have looked at your example file in QGIS and Global Mapper and they 
> show distance like JOSM. I don't know why there is so big difference. My 
> guess is that it could be caused by spherical versus ellipsoidal model 
> of the Earth. Maybe you could test algorithms based on Vincenty's 
> formulae? See for example:
> 
> http://www.gavaghan.org/blog/free-source-code/geodesy-library-vincentys-formula-java/
> 
> http://geographiclib.sourceforge.net/html/java/
> 
> -- 
> Best regards,
> Andrzej
> _______________________________________________
> mkgmap-dev mailing list

> mkgmap-dev at .org

> http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev

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