[OSM-talk] Advanced Relationships

[Martijn van Oosterhout]

On 6/20/07, Frederik Ramm <frederik at remote.org> wrote:
> Hi,
>
> >>> Sure, but we should also have a serious discussion about what to do
> >>> about the street number data that already exists in the DB. Currently
> >>> segments are the natural place to put such data and you're not
> >>> providing a useful alternative...
>
> There are 120 instances of street number data in the whole planet file.

One effect of non-standardised tags. This bounding box contains nearly
600 segments with housenumber data:
http://www.openstreetmap.org/index.html?lat=53.00124355770805&lon=6.5719647173087985&zoom=11
(look for housenr). Who knows where else.

> This is not true. A segment could span a kilometre or more and thus is
> not a natural bearer of house number data.

I disagree. For a routing application the segment is obviously the
closest point it's going to be able to route to, even if it is a
kilometre long. It may need some hint as to which end, but it needs to
route to a point *on* the segment, not somewhere near to it.

> The segment as we know it is just a primitive building block for ways
> and should not be used to attach information to it: People regularly
> change the shape of a way by moving its nodes, inserting or removing
> segments, or splitting a segment in half to attach another way they just
> mapped. All these operations will render house number information
> attached to segments useless. Also, if you have a curved way between two
> nodes, approximated by 5 segments, how do you want to add information
> about house numbers there?

I don't think anyone denies housenumbers are going require significant
editor support to make it work. You just can't remove segments without
providing some alternative for storing the data, because the data
already exists in the DB now.

> But segments in their current form (and in the way they are treated by
> users and editors) are not a suitable vehicle for this.

I never said they were. I only said that we need to think of (and
implement) the alternatives *before* removing segments, not after.

Have a nice day,
-- 
Martijn van Oosterhout <kleptog at gmail.com> http://svana.org/kleptog/