[mkgmap-dev] housenumbers and addr:interpolation

Mon Dec 1 21:28:50 GMT 2014

> Both: associatedStreet and addr:interpolation are documented:
> http://wiki.openstreetmap.org/wiki/Relation:associatedStreet
> http://wiki.openstreetmap.org/wiki/Key:addr#Tags_for_interpolation_ways

"As long as we don't have a node or building outline for each 
house(number) along a way, it's also possible to use automatic number 
interpolation. For that, draw a way connecting the existing house 
numbers and mark it with the type of interpolation as shown in the 
picture above. Additional tags such as addr:street=* are still added to 
the objects with the addr:housenumber=* tag, the interpolation way only 
gets the addr:interpolation=* tag. "

So in other words, addr:interpolation should connect two or more 
elements that are fully tagged with addr:housenumber and addr:street. So 
there is no improvement in adding an addr:interpolation handling to 
mkgmap. When removing the interpolation line you still have the single 
elements with the housenumber information. They are already converted to 
the Garmin format which automatically interpolates.

There is one exception: In case an interpolation covers more than one 
street segment:
        ´|
========┴=======
  1------------15

The interpolation 1 to 15 spans over the crossroads. The street have two 
segment so the current algorithm ignores the interpolation and would 
assign housenumber 1 to the left and 15 to the right segment. This could 
be the place where mkgmap might add two virtual housenumber nodes e.g. 9 
and 11.

>
> See statistics too:
> https://taginfo.openstreetmap.org/keys/addr:interpolation
> https://taginfo.openstreetmap.org/tags/type=associatedStreet
>