[Talk-ca] [OSM-talk] Addr:streetnumber:first;last:left;right

[Marcus Wolschon]

On Tue, Apr 7, 2009 at 8:25 PM, andrzej zaborowski <balrogg at gmail.com> wrote:

>> createInterpolationWay(way w, int offset) {
>>
>> Node startInterpNode = new Node(w.getNode(0).location +
>>   offset * w.getNode(0).getNextSegment().vectorNormalLeft());
>>
>> foreach (Node n in w.nodes except 0 and last) {
>>  Vector last = w.getNode(0).getLastSegment().vectorNormalLeft();
>>  Vector next = w.getNode(0).getNextSegment().vectorNormalLeft();
>>  Vector normalVector =
>>          new Vector((last[0] + next[0]) / 2,
>>                     (last[1] + next[1]) / 2).normalize()
>>  Node interpNode = new Node(w.getNode(0).location +
>>     offset * normalVector );
>
> If you just add the normal vectors it won't look very natural because
> the angle will determine the offset between the interpolation way and
> the road.


That is why I normalized the resulting vector, thus giving it
a length of 1. The offset will thus stay constant.

>> }
>>
>> Node endInterpNode = new Node(w.getNode(last).location +
>>   offset * w.getNode(last).getLastSegment().vectorNormalLeft());
>>
>> }
>>
>> Not as difficult as andrzej thought it would be.
>
> This isn't the difficult part, ump2osm implements this too.  The
> difficult part is the reverse mapping, if you wanted to convert OSM
> data back into a Garmin compatible format.
> (difficult but doable, ofcourse)

That is where associatedStreet and the trivial distance betwen a point
(node with addr:housenumber) and  line (segment of the ways of the nearest
nodes) comes into play.
I implemented it. It was easy to do and is much more reliable then
I would have thought when we specified the Karlsruhe Schema
at the Geofabrik last year.

Marcus