[mkgmap-dev] Options

Mon Dec 10 12:34:41 GMT 2012

Hi Felix

Thanks for your thoughts.

> --ignore-maxspeeds  , Strong Objection. For a bicycle map it is really
> needed. I don't want mkgmap messing around with maxspeeds. It's also
> about performance, why calculate something if it's not needed.

What do you object to?

I'll explain what I mean by "move to style".

My idea of the style system was that everything that determines how
osm tags get converted into garmin terms was to be controlled by the
style file. The mkgmap code should not be looking at a hardwired tag
like maxspeed at all. If you want to change road_speed based on
maxspeed it should be written in the style.

For a start maxspeed is the wrong tag to use, a tag for average or
typical speed would be better where such a thing exists.  At the very
least, it should only revise the speed down, never up (I think you
might have made that point before), because a good road going through
a town may be be slower because of speed restrictions but a single
track road is usually not suitable for driving a 60mph just because
that is the speed limit.

> --ignore-turn-restrictions ,Strong Objection again. We don't have

The same applies, the style should be able to select cycle relevent
turn restrictions if they exist, based on the style that you
write.

So OK, that's not going to happen soon, because the style system would
have to be extended a bit to make it possible. So we will probably
have to retain the option for now. But only because there isn't a way
of specifying which tags should be used for turn restrictions in the
style.

> --delete-tags-file= It's a performance improvement. However it was once
> broken. Someone said it's working again. I once moved it into my style
> where it makes more sense. Don't know how much quicker it can make mkgmap.

I doubt that there is much performance improvement, especially after the 
style re-write.

I thought it was mainly so you could easily remove things from the map
while still using the default style.

..Steve