[mkgmap-dev] Fun with splitter tile descriptions

Sat Sep 12 13:37:37 BST 2009

> Thanks Johann, this sounds like quite a reasonable approach too. It shouldn't 
> be too hard to add in to the splitter (eg by tacking the info on to the density 
> map, or by holding on to the is_in data until the areas are known then calculating 
> the names as a separate step). Looking at a few osm files the is_in tags 
> and their values seem inconsistent at best though so I don't know how easy 
> it would be to get sensible/consistent data from them. Another possible issue 
> is that osm files without the tags wouldn't work at all. 
Yes, thats true. As far as I can remember, the is_in tags was very 
inconsistent. But I had hoped my algorithm is flexible enough to ignore 
this inconsistency. The idea was to extract each name at each level of 
the is_in tag. So if I take for example is_in = 
Germany,Bavaria,Munich,suburb,street name,.... then I will count the 
frequency of all five words. With statistical probability Germany will 
be the most used word in this tile.
Afterwards I try to find unique names for the tiles. The name Germany 
will be occur in nearly all tiles, so it is not unique and will not be 
used. Also the region Bavaria will be in more then one tile and will not 
be used. If the city Munich is contained fully in one tile, the name 
will get taken, otherwise I will go down to the next. So I will get the 
most used name which is unique for this tile.

> If you do have some 
> code that deals with filtering/sanitising the is_in data I'd be interested 
> to see it however as it sounds like it would be worth investigating further.
>
>   

Find attached a patch, which works against the relative outdated R37. 
I've tried to update to the recent splitter, but it wont work. There was 
some structural changes from SubArea to Area.

Regards,
Johann

>   
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