[mkgmap-dev] Too many pois on multipolygon areas

Tue Sep 27 18:27:10 BST 2011

>
>
> Minko (ligfietser at online.nl) wrote:
>
>> I have enabled the add-pois-to-areas option, because this way I can
>> search for a certain tag that is placed on an area like landuse=*,
>> tourism=* or building=yes. But sometimes those pois are cluttering
>> the map, especially if this area is a type=multipoygon relation.
>>
>> Take for example this multipolygon relation:
>> http://www.openstreetmap.org/browse/relation/949481
>> tourism=zoo is tagged only once on the outer way:
>> http://www.openstreetmap.org/browse/way/61046378
>>
>> However, the multipolygon function of mkgmap splits this area up in
>> several parts (to render the inner islands, which is fine) but it
>> also creates too many pois by the add-pois-to-areas for this one
>> tourism=zoo area: http://img546.imageshack.us/img546/5763/zoow.jpg
>>
>> I'd like to see just one elephant icon instead of several. Is it
>> possible to execute the add-pois-to-areas action before the
>> multipolygon action takes place?
>> Or is it possible to set some rules in the style file to make some
>> exceptions for areas with type=multipolygon?
>>
>
> This is a known issue
> (http://wiki.openstreetmap.org/wiki/Mkgmap/known_issues#Too_many_POIs_for_a_given_area_that_has_been_split_using_multipolygon_code).
>
> WanMil had a look at it a few months back and concluded that there
> wasn't a quick fix
> (http://www.mail-archive.com/mkgmap-dev@lists.mkgmap.org.uk/msg07431.html).
>
> I would really like to see this bug fixed as it can add many duplicate
> POIs to a map.
>

Maybe it's not be too difficult to fix that. Here is my idea:
Just before the style conversion one point for each polygon is added 
with a copy of all tags plus mkgmap:poly2poi=true. Polygons contained in 
or created by a multipolygon are excluded but additionaly one point for 
each multipolygon is added.

Now the rules in the points style are applied automatically.

Sounds too simple...? Any objections to such a solution?

WanMil