[mkgmap-dev] Missing ways part 1

Thu Oct 21 23:30:27 BST 2010

I have investigated further and this is what I have found.

- I have discovered a section of motorway that is missing, so it appears
that all types of way are affected.

- The missing ways that I have spotted, all continue beyond the overlap
region. They contain nodes within the overlap region but none end within
the overlap region.

- The output files from splitter contain the missing ways and they are
complete; i.e. the way has all its tags and a complete list of its node
ids. What is not there, is what you would not expect to be there: the
definitions of the nodes which fall beyond the overlap region - their
latitudes and longitudes. The effect of this on JOSM is that it draws
the nodes that are defined but it does not draw any part of the way.

- Splitter does not introduce nodes at the tile boundaries (or if it
does, they are not displayed in JOSM, either on the map or in the
inspector/Advanced object info).

It would seem that mkgmap discards these defective ways.

This bug could be fixed in either of two ways:
a) Clip the ways in splitter so they are no longer defective.
b) Modify mkgmap to accept defective ways and clip them itself.

At this point it needs someone with a detailed knowledge of the
software, to say how the interface between splitter and mkgmap should
work, i.e. whether a) or b) is the correct approach. Only then could
bugfixing efforts begin. I hope that the additional information I have
provided, will make it that much easier to trace and fix the bug.