[mkgmap-dev] Fun with splitter tile descriptions

Fri Sep 11 20:12:20 BST 2009

I played with an similar thing some time ago, a year or so. My algorithm 
was not searching for the biggest city, but counted the 'is_in' tags of 
the osm data. The idea behind it was that should scale with different 
resolutions. With big tiles it should name the tiles with the names of 
boundaries, if I break it down into small tiles it should take the names 
of the cities and villages. With statistical probability in a big city 
exists much more is_in tags as in a small village.

This was inedependent of the geonames service and fully based on the osm 
data.

As far as I can remind, the results worked in general, but the code does 
not fit well into the splitter. I would have to search on my harddrive, 
if the code lays around somewhere.

Regards,
Johann

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