[mkgmap-dev] default style lines enhancements

Tue Jul 28 10:58:30 BST 2020

Hi all

In some major walking areas there are networks of paths with a few car
parks around the edge, normally set 100m or so into the park/woods. The
free maps one can obtain show suggested trails and these trails often
cross multiple car parks. The maps probably don't show a path within
the car park and there is no physical manifestation of it.

Without "paths around car park", if I try to use my device to generate
a walking route to some feature in the area (or back to the start), it
will probably generate a route that leaves the area, gets onto the
closest road, and re-enters elsewhere. Or it might give a "Route
Calculation Error" because paths closest to the start or end are not
connected to the rest of the network.

With the data as it stands, for sensible routes in the above situation
and others as expressed in my earlier email, mkgmap needs to generate
footways that join up all ways that lead into the car park with a
footway. With the current technology this can be done with
circumference footway and mkgmap:set_{semi_/un}connected_type provide a
really good way of not doing this where the footway won't solve any
routing issue and might cause routing island problems.

I wouldn't object if OSM mappers joined all paths and the entrance
road/parking aisles within the car park and maybe there should be a
policy to do this and then there is no problem.

However, there is a good argument that the correct OSM mapping is to
show paths exactly as they are and not have to invent and add 'virtual'
bits of footpath just to keep routing engines working sensibly because
"mkgmap expects it like that".

Other things that have been mentioned:

- What about a path that runs up to or along the side of a car park but
there is no access between them, eg an enclosed car park with a road
along-side. I'd say that this is just incorrect mapping if the car park
shares a node with the road but there is a barrier between.

- If starting within the car park, the route might tell you to walk
around the edge rather that direct to the highway. Yes and no; it will
plot a route to the closest edge and then to the best exit for the
final destination; It should be obvious to the GPS user that they can
just walk directly to the best exit. Without the change the only option
you might get is onto the road network which could be entirely wrong.

Ticker