[mkgmap-dev] Improvements to OSM Garmin maps

Fri Feb 11 13:52:46 GMT 2011

Hi guys,

I have recently started making my own Garmin maps for my Nuvi 265WT 
based on OSM planet extracts. I have been downloading ready-made maps 
from raumbezug.de, but now I would like to improve on their maps. Their 
UK/Ireland maps appear to be built with --drive-on-right, which causes 
the odd peculiar routing instruction plus the wrong icons are shown for 
roundabouts. But there are some other things I would like to improve on, 
and I would appreciate any tips or feedback anyone may have about my 
ideas. Do they sound feasible? Or have better brains than mine already 
tried and failed?

* Spoken routing instructions at motorway/trunk/etc junctions, forks and 
slip roads
With OSM Garmin maps I often hear simple instructions like "keep right 
on A12" whereas the official Garmin maps manage to say something more 
complete like "Take exit 4, on right, onto A12 towards NewTown". Also in 
the official maps the single line of information about the next junction 
displayed at the top of the map display is not (usually) equal to the 
spoken "name" of the junction, whereas with the OSM maps it always seems 
to be equal. I am trying to find if there are "magic combinations" of 
tagging, mkgmap options, code and stylesheets to see if these points can 
be improved. Initial experiments have shown that small improvements are 
possible, but I am not getting anywhere near the richness of the 
information from the Garmin maps.

* Spoken street/city names
I have my unit set to UK English, but I live in the Netherlands. With 
the Official maps, the TTS makes a very valiant attempt at pronouncing 
Dutch street/city names in the Dutch way, albeit (I suspect) using 
English phonemes. With the OSM maps, the names are pronounced as if they 
were English, which is sometimes just "unclear" but very often 
entertaining. With the official maps, something somewhere knows it 
should be pronounced in Dutch. It could be a question of a header value 
in the IMG, it might be some kind of tag on each string to indicate the 
language, or it might be that each string is also stored in a phonetic 
form for use by TTS. Any ideas?

* Speed limit icons
These are not shown with the OSM maps. How can these be enabled, based 
on maxspeed tags?

I am not initially planning to modify the java code; I would like to see 
how far I can get with tagging, stylesheets and options. My assumption 
is that TYP files only concern the way things are displayed, and are 
irrelevant to the above points.

Colin