[mkgmap-dev] addr:place support

Sat Apr 4 14:03:47 BST 2015

Hi all,

some month ago we discussed the idea to implement addr:place support.
It it assumed that an address has addr:housenumber and either addr:place or 
addr:street. Up to now those with addr:place are ignored.
It is also assumed that the addr:place tag is used in hamlets and small villages
and that the roads in such a hamlet have no name.

I've coded the following simple approach:
 For each element (node/way) with addr:housenumber=* and addr:place=* and addr:street!=*
search the nearest routable way that has no name (mkgmap:street!=*)
If the closest road is within a given range (150m), store the place name as a possible road
name. Perform a 2nd search to find also the closest road with a name or ref.
If we find exactly one possible name for the road, use it.

Problem 1)
What should happen if the algo finds multiple possible names for one road?

This happens quite often. Typical reasons:
a) The road is rather long and connects two or more hamlets.
I think it would be best to split the road so that we can give it different names.
Maybe split into three parts so that the part between the hamlets stays unnamed.
b) The road is near the boundary (or on the boundary). Houses on the left belong
to hamlet A, the others to B. This is a bit more complicated.
I see these possible solutions:
b1) ignore the road and the houses which are close to it (address search will not find them)
b2) duplicate the road and give the original road the name A and  the copy the name B

Problem 2)
What should happen when the closest road is one with a name and the closest unnamed road
is too far away?
I think in many cases we have to treat this as an error in the OSM data .
Problem 2b)
What should happen when the closest road is one with a name and the closest unnamed road
is a bit more away, e.g. 20m and 50m ?
I fear this will require complex analysis, so it will be ignored for now.

Problem 3)
What should happen when the closest road is one with a ref, but no name?
I think this is like problem 1). We can split the road, give the part through the hamlet
the name of the hamlet (in addition to the ref) 

Do you see other possible problems or solutions? Is one of the suggested solutions a no-go?

Any input is welcome.

Gerd

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