[OSM-talk] Collected Way support

[David Groom]

----- Original Message ----- 
From: "Richard Mann" <richard.mann.westoxford at googlemail.com>
To: "Talk Openstreetmap" <talk at openstreetmap.org>
Sent: Thursday, July 09, 2009 3:51 PM
Subject: Re: [OSM-talk] Collected Way support


> It looks too complicated to me.
>
> Given that certain tags apply to ways but not nodes, would it not be
> possible to imply some meaning by attaching bridge=yes+layer=1 to a node 
> on
> a way, to mean the segment between this node and the next?
>
> Then the way wouldn't need to be chopped up in the first place.
>
> Richard


Richard

This is not some theoretical point, it's what is happening to the data, and 
ways ARE becoming very fragmented

Consider the situation below, which actually is fairly simple only, in 
practice where more bus routes occur, speed changes, the way goes goes over 
a bridge etc...the way gets split into many, many more parts.

A - G, say "High Street", starts off as a nice simple linear way,
D - J  is a road called "Long Way"
B - H and C - K are footpaths

at E the speed limit on High Street changes from  say 30kph to 40 kph.

a bus route travels from A - D along High Street, but turns on to Long Road 
along D - J
a long distance walking route uses footpath  K - C part of High Street C- B, 
and then continues along footpath B - H


        H                J
         |                 |
         |                 |
         |                 |
A------B-------C-------D-------E--------F--------G
                  |
                  |
                  |
                  K


Currently in order to map this simple situation in OSM way A - G has to get 
split in to 5 ways.

A - B, B- C, C- D, D - E, and E - G

It's necessary to split the way at B & C, so part B - C can become part of a 
relation grouping K - C, C - B, and B - H all for the long distnace route.

It's necessary to split the way at D so the relation for the bus route 
doesn't include parts D - G

It's necessary to plt the way at E so the spped limit can change

David


>
> On Thu, Jul 9, 2009 at 3:17 PM, David Groom <reviews at pacific-rim.net> 
> wrote:
>
>> For various reasons, for example the need to put different max_speed tags
>> on
>> different parts of a way, the need to split ways so individual parts can
>> become part of a relation, etc, even "simple "  linear ways are becoming
>> very fragmented.
>>
>> I was just wondering what the current state of client support (renderers,
>> editors, routing programs etc) is for collected ways [1].
>>
>> David
>>
>> [1] http://wiki.openstreetmap.org/wiki/Relations/Proposed/Collected_Ways
>>