Talk:Unwayed segments

From OpenStreetMap Wiki
Jump to navigation Jump to search

Discuss unwayed segments here:

Two-phase approach

The two-phase approach has been necessary because, generally, the (Java) applet has not been suitable for large-scale editing.

In addition, people often held off creating ways when the editors did not support splitting or joining ways. This is no longer the case.

For those who wish to continue with two-phase editing, I recommend adding an option to JOSM which displays ways without tags in a different colour. (Excluding 'created_by', of course.) This is a very simple way of matching the previous functionality, while still removing the need for novice users (and the impatient :) ) to have to use segments. --Richard 18:31, 24 May 2007 (BST)

Aha. So Potlatch is hiding the concept of segments to make things easier for the novice/impatient user. That makes sense.
But if we no longer allow unwayed segments then there's something we're missing. Today I also wrote Yahoo! Aerial Imagery#Sketching over the imagery. So here's the thing... 'sketching' over the aerial imagery is desirable. The two-phase approach is desirable. It's very quick and easy to sketch out a map based on the aerial imagery, and previously this was facilitated by unwayed segments in the Java Applet.
It doesn't have to be done using unwayed segments. But what's the replacement?
-- Harry Wood 21:15, 24 May 2007 (BST)
I'll try to answer my own question
Maybe we just sketch in ways, and leave them without names. The phase one mapped areas will get mixed indistinguishably with the more finished areas, so I think we'd need a way of easily visualising areas full of streets which don't have names yet (the areas where the all-important surveying work still needs to be done)
Do we identify sketched in areas by the lack of 'name' tag, or by 'FIXME' tags? If FIXME tags, then we want to have a way of putting Potlatch into "sketch mode", so that it leaves a trail of FIXME tags.
The Osmarender layer currently hides streets with no name tag. Does Mapnik too? I'm not sure. Maybe we need to put in name="" tags (empty string). Is that allowed? We would want to see the sketched in streets in the slippy map wouldn't we?
Some details I'm not clear on -- Harry Wood 21:16, 24 May 2007 (BST)
Yep, you've grasped what I was proposing. "Sketched in areas" are best identified by the lack of any tag, IMHO: as I said above, JOSM could display these in a different colour. After all, there are no circumstances under which you should consider a way 'complete' without any tags. (Again, excluding created_by, which really shouldn't be in the tagspace but that's another discussion.) --Richard 12:40, 25 May 2007 (BST)

Way topology

Ah. I'm pleased to see that someone has brought this issue to the fore. I had been using unwayed segments in Walthamstow very heavily prior to the last two weeks for sketching purposes. Others have already mentioned elsewhere that one of the reasons for wanting "sketched" roads is because the sketcher doesn't always know the road names yet. This is true. But for me a more important (though clearly related) reason for not wanting to draw ways during "sketching" was one of not knowing the WAY-TOPOLOGY I desired at that early stage. For example, ways encapsulate not just names, but also categorise flow and connectedness. If I have three roads meting at a point, I might want 3 separate ways (if all three roads have different names) or maybe two ways (one passing in and out with the second budding off). OK that's not so bad, I could always split a way later. But worse some long roads may pass MANY intersections along their length, but at the time of skethcing from aerial photography it may not be at all clear at each junction which path the "dominant" road takes while maintining its identity (if it doesn't stop). It is just not possible to (efficiently) create longish ways right from photographs at 1st attempt. A second pass (weeks later) is very necessary. As one of the commenters above said, we do need to retain the *functionality* of un-segmented-ways (though not necessarily using exactly the same *mechanism* as before - FIXME tags may be fine for me - other solutions are no doubt possble) because the functionality is very necessary for producing urban maps efficiently. I just hope the solution doesn't become a nightmare of contorted hoop jumping. Personally what worked best for me was un-wayed segments in applet followed by WAYS in JOSM. If potlatch is the way forward, then I'd like to stick with something along those lines. Many one-segment ways in potlatch (not long ways I'm going to have to break up later) followed by wayification in JOSM. kesterkester

Given that JOSM and Potlatch both have easy split way/join way functionality, there is nothing stopping you sketching them in as ways and then splitting/combining afterwards. The only significant omission is that Potlatch does not have support for reversing/reordering ways, though this will come shortly.
  However, that said, if you prefer the earlier way of working, the easiest thing to do would be to restore the old Java applet on the site, then implement a user preference so that you could choose to use the applet rather than Potlatch. (In other words, Potlatch would appear on the edit tab until you set a preference to 'Use Java applet', then the applet would appear instead.) Feel free to raise a ticket on trac to this effect, or better still, check out the code and start hacking. :) --Richard 08:53, 26 May 2007 (BST)

Unnamed ways

Generally I avoid unwayed segments. I instead create ways using the Tways plugin for JOSM and tag them, but give them no names. Some other editors do this as well.Andrewpmk 01:19, 5 September 2007 (BST)

Yeah so maybe that's a third approach. We have 'unwayed segments', 'untagged ways', or 'unnamed ways'. A good advantage of unnamed ways is that the renderers actually show them (now!), but that is a double-edged sword.
We don't want to give mappers or visitors the impression that these sketched areas of the map are finished. Visitors will zoom in and think "Hang on. No street names. This map coverage is a bit inconsistent". Mappers will pan around and fail to notice where the all-important surveying work still needs to be done. I worry that if I am sketching over Yahoo imagery as a "phase one", this will be seen as polluting the quality of the maps, where people have done surveying. Surveying is necessary. I never wanted to suggest otherwise. Also surveying is very much the *hard work* of creating a map. It feels disrepectful to slap in a load of roads based on aerial imagery, which will get rendered with equal weight alongside fully surveyed roads.
In my opinion, whatever mechanism we use to represent a sketched road, this should get rendered, but less prominently than a fully mapped road. Until a few days ago osmarender layer fulfilled this function rather elegantly with its treatment of unwayed segments.
Going forward I'd suggest untagged ways and/or unnamed ways should be rendered by osmarender (and why not also Mapnik?) in the same faint grey style
-- Harry Wood 10:45, 5 September 2007 (BST)