[mkgmap-dev] Fun with splitter tile descriptions

Wed Sep 9 15:02:11 BST 2009

Nice idea! I'll put that on the todo list for incorporating into the splitter, 
sounds like a very useful feature to add. What might be even better is if 
I use those webservices to generate a data file that can be distributed with 
the splitter itself, so people don't need to have an internet connection 
when splitting. The static lookup could also be customised to suit individual 
needs if so desired.

CG> I found it somewhat annoying that my tiles always had identical
CG> generic descriptions such as "OSM Map". It made it very difficult to
CG> recognise which tiles belonged to which areas, in particular when
CG> attempting to select specific tiles on my GPSr. Since my maps could
CG> have over 200 tiles, it was tedious to add descriptive names
CG> manually. To solve this, I performed the following small hack, which
CG> might be interesting to others with a similar predicament:
CG> 
CG> - I created a Perl script which read the tile boundaries from the
CG> areas.list file generated by splitter.
CG> 
CG> - For each bounding box, I called a webservice from GeoNames to
CG> retrieve a list of populated areas (cities, etc.) within the tile.
CG> 
CG> - For each populated area within the tile, I called another
CG> webservice to determine the population of that area.
CG> 
CG> - I determined the city with the largest population, and then wrote
CG> the ISO country code and name of the city to the description
CG> parameter in template.args.
CG> 
CG> To my astonishment, this worked rather well.
CG> 
CG> Here is an excerpt from the resulting template.args file:
CG> 
CG> [...]
CG> mapname: 23000223
CG> description: EE-Tartu
CG> input-file: 23000223.osm.gz
CG> mapname: 23000224
CG> description: FI-Espoo
CG> input-file: 23000224.osm.gz
CG> mapname: 23000225
CG> description: FI-Helsinki
CG> input-file: 23000225.osm.gz
CG> mapname: 23000226
CG> description: RU-Saint-Petersburg
CG> input-file: 23000226.osm.gz
CG> [...]
CG> A description of the webservices I used is at
CG> http://www.geonames.org/export/ I used the GeoNames Perl client
CG> module to parse the webservice results; this may not have been the
CG> most efficient.
CG> 
CG> There are of course many other ways of doing this, and other
CG> services and data which can be used. Perhaps this will inspire some
CG> of you to create a better solution.
CG> 
CG> Cheers.
CG> 