[mkgmap-dev] help neededFrom GerdP gpetermann_muenchen at hotmail.com on 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 -- View this message in context: http://gis.19327.n5.nabble.com/help-needed-tp5813164p5813323.html Sent from the Mkgmap Development mailing list archive at Nabble.com.
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