Talk:Link (highway)

so the admonition against tagging for the renderer does not apply here.

Everybody can stop reading after that half sentence. This is a rendering problem, so fix the rendering rules, not the tagging. I thought that this was clearly stated in the original mail discussion. --Cartinus 17:16, 2 July 2010 (UTC)

What's the rendering problem? What's being said there is that whether it's tagged (for instance) primary_link or secondary_link makes no difference to anything except the renderer. --NE2 18:48, 2 July 2010 (UTC)

To render a link properly, it needs to start at one 3-arm node and end at another (3 or more). You get rendering artefacts if it ends at a 2-arm node (unless the two arms happen to be the same colour). The other thing you need to do is to put the link under the two 3-arm nodes at each end. So fine, you might think, just render links under everything (this is what Mapnik currently does). Unfortunately you need to render them on top of any intervening 3-arm node (eg a service road coming out in the middle of a link). The least amount of information you therefore need (to render it neatly) is the lower of the two classifications that the link joins. You render the link just under the lower of the two classifications, and any intervening even-lower classification road goes under the link. If you would prefer the link to be the colour of the higher of the two classifications that the link joins, you also need to know the higher-of-the-two classifications. The higher-of-the-two-classifications is (per the wiki) used as the basis of the highway tag (though this doesn't always happen, because it looks a mess unless it's reasonably symmetrical). Maybe the lower-of-the-two-classifications could be recorded with a links_lower tag. It would be simpler if we recorded the lower classification in the highway tag, and the higher one in a links_higher tag, but maybe life isn't going to be that simple. If you add both links_lower and links_higher tags, then a bot can sort it out one day.--RichardMann 22:30, 2 July 2010 (UTC)

Naming links

How should links be named (to avoid them showing in red in potlatch)?

Don't tag for the editor. If the link has a name, use that. If it doesn't, don't enter a name. (Roughly) all alerts of the data not complying with that/each editor's rules are notices only. Alv 22:23, 22 October 2010 (BST)