[mkgmap-dev] [PATCH] make gps report correct exit when routing through roundabouts

Wed Feb 11 16:47:36 GMT 2009

Here's a new version of this patch.

What it does is an ugly hack but if it fixes the problem without hideous side effects it will probably serve until some better way of solving the problem is devised.

It is no longer enabled by default, you need to specify the --frig-roundabouts
option. By default the "frig factor" (influences how far the new points are
away from the centre of the roundabout) is set to 0.25. You can specify a
different value as the option value: --frig-roundabouts=0.1

Large values tend to make the roundabout uglier so it would be worth
experimenting to see what the minimum frig factor is that will stop the
gps from reporting the wrong exit.

You can also enable frigging for an individual roundabout by tagging the OSM
XML with the "mkgmap:frig_roundabout" tag which can either be set to a valid
(floating point) number to specify the frig factor or just some other string
that will make it use the default frig factor.

This patch also avoids putting in new points if the new point would be
less than 5 or more than 100 metres from the adjacent points. This may
stop the exception reported by Paul, but probably not.

This patch replaces the version from earlier today and is for the current
nod branch in SVN.

As always, feedback is appreciated.

Cheers,

Mark

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