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[mkgmap-dev] Routing

From Steve Ratcliffe steve at parabola.me.uk on Tue Jan 14 14:23:51 GMT 2014


I've been looking into routing and I have updated NodDisplay
so that it mostly works on any file.
I've not discovered much that wasn't known before, apart from
a compact way of storing directions that is probably suitable
for short roads. There is a destination road-class field in
the node flags that we do not seem to set, so we should fix that.

I am in the process of updating the nod.txt file with everything I've
learned so far.

There are also two new programs.

1. test.check.NodCheck reads in a NOD file and cross checks
    various things. So it can tell you if the angle in NOD is similar
    to the actual angles between two nodes.  Files give lots of errors,
    but it doesn't mean that they are wrong, just things to look into.

2. test.svg.Main Converts the routing graph to an SVG file that
    can be displayed in inkscape (and perhaps other SVG viewers).
    The idea is to be able to visualise what is going on. Only a
    portion of the file is processed, since the output is very

They are only of use if you want to look into the routing code. The
output will make no sense at all if you are not familiar with it,
and possibly even if you are ;)


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