[mkgmap-dev] removeShortArcs_v4.patch for regression in r2448

Sun Feb 3 22:52:09 GMT 2013

Hi Gerd

> the errors reported by NetCheck occurs in ~ 50% of my input files (DACH).
> I don't think that it is a special case in the OSM data.

Quite by accident, I found a tile that failed the NetCheck test
from Jan 2011 and version r1773. So the problem has existed for
a long time - although it was very rare with that version - I
found only one tile.

I am still guessing, but in LinePreparer we throw away lines that
have less than two (or three if a polygon) points that have different
coordinates - so lines that have a zero length (or polygons that don't
have an area).

This is probably far too late and may mean that pointers
are left pointing to the wrong thing.

If this is the problem, then we do need to remove any zero length line.
The remove short arc code will do this, but perhaps for non-roads all
we need is a quick check for zero length lines.

..Steve