[mkgmap-dev] documentation of new option in branch

Mon Nov 4 16:35:38 GMT 2019

Hi Gerd, Good work. I suggest the following:

--check-routing-island-len=INTEGER
	Routing islands are small road networks which are not connected to
other 
	roads. A typical case is a footway that is not connected to the main
road 
	network. These islands can cause problems if you try to calculate a
route
	and the GPS selects a point on the island as a start. It will fail
to calculate
	the route even if a major road is only a few steps away. If this
option is
	specified, then mkgmap will detect these islands. If the value is
	set to zero,  mkgmap will simply report the islands (you will need
to
	set uk.me.parabola.imgfmt.app.net.RoadNetwork.level=INFO to
	activate logging of the message). If the value is greater than zero,
mkgmap
	will mark islands with a total length less than the specified value
in metres
	as not routable. The default is for the check to not take place.

If the default is for the check to not take place then there is no need for
the slightly arbitrary negative value processing.

Regards,
Mike
-----Original Message-----
From: Gerd Petermann [mailto:GPetermann_muenchen at hotmail.com] 
Sent: 04 November 2019 13:58
To: mkgmap-dev at lists.mkgmap.org.uk
Subject: [mkgmap-dev] documentation of new option in branch

Hi all,

I think the work on the branch is almost done.
Attached is a patch to add documentation for the new option. 
Please help to improve it:

--check-routing-island-len=NUM
	Routing islands are small road networks which are not connected to
other 
	roads. Typical case is a footway that is not connected to the main
road 
	network. These islands can cause problems if you try to calculate a
route
	and Garmin selects a point on the island as a start. It will fail to

	calulate the route even if a major road is only a few steps away.
	When calculating the NOD data mkgmap detects the islands. The option
	--check-routing-island-len=NUM can be used to tell mkgmap that
islands with 
	a total length below NUM meters should not be written to NOD. The
effect is 
	that the corresponding roads are visible as usual but they are not 
	routable.
	A negative value for NUM means that mkgmap skips the island check.

ciao
Gerd