[Openstreetmap-dev] Line Segments without Streets are Streets?

[Tom Carden]

Immanuel Scholz wrote:
> Let me ask it another way by explaining my current problem:
>
> I like to code the creation of streets without the need to create line
> segments for every node the street belong to. The user should just draw
> a line between several nodes in a row and get a full street created.
>
>   

Yes, that sounds like a sensible user interface.  There might even 
already be a trac ticket requesting it to work like that on the applet. 
I don't personally think it's super important whether people add 
individual segments one at a time or if they add continuous streets 
(perhaps with curves etc).  Some people have mentioned that it would be 
nice to input curves/paths in the way that Adobe Illustrator does it.  I 
don't think it's high priority but I agree.

> Now, if the user draw such a street only from one node to another, I
> could either:
> - only create a line segment without a street
> - create a line segment, then create a street containing only this line
> segment
>   

Really doesn't matter does it?  If as a client author you receive a lone 
line segment which isn't a street, you could choose to represent it as a 
street anyway.  The latter could be done automatically on the server if 
we want.

> So to decide what's better, I ask, what the intention of "line segment"
> in the database is. Some month ago, I was sure, that this intention is
> only to serve as pieces of tracks, but since 0.2 and the users starting
> to give line segments the name of real world streets, I ask whether my
> idea of "line segment" is right.
>   

It's still to serve as pieces of tracks.  We need a higher level data 
type such as street to do lots of the interesting things we want to do.  
The reason you need to be able to apply names/tags at the segment level 
is that streets aren't the same all the way along.

This is classic iterative development - the current interface very 
closely tracks the available data model and API... but that won't be the 
case forever.  As things settle down the abstractions and user 
interfaces will mature.

> Currently the applet draws line segments like streets (to me they look
> like I would expect a street to look like ;). Maybe this is because the
> server does not understand the concept of tracks yet.
>   

And because the applet doesn't.  I would imagine that the next big 
update to the applet would include combining segments into streets 
(we've already talked about how the selection model for this might work 
like selecting text in a text editor, and someone recently gave a good 
definition of a 'block' which would allow quick editing of multiple 
segments).

> I can, of course, code in a way that assume that every line segment is a
> track by itself (means as example: draw it like a street), but I don't
> want to do this if the applet will change as soon as the server
> understands tracks and then assume single line segments without tracks
> attached to be no streets but something unfinished thing..
>   

I think it's worth mentioning here that "track" is a bad name for a 
collection of segments.  The term "track" is better for the raw GPS/GPX 
data we see in the editor.  I'd prefer "street" for now, and I'm open to 
something like "way" that Andy has been talking about if we want to 
represent other collections of segments.

Tom.