OpenStreetMap

The Three Stigmata of Potlatch Edits

Posted by NE2 on 5 September 2012 in English (English)

The following can be observed in many edits done in Potlatch 2, especially in simple mode.

  1. Nodes as one in two. Often a way will be drawn to intersect another not at an existing node but right next to it. It seems that PL2 has a problem with the minimum distance at which it assumes the user means to connect two nodes, and no obvious indication after-the-fact that something is wrong (since, unlike JOSM, nodes only appear when you mouse over a way). This causes not only redundant nodes but bad errors. For example, where a dual carriageway ends, there may be a tiny bit of one-way single carriageway, due to the node at the end of one direction being different from the one where the other direction and the single-carriageway continuation join. Hence the road is not routable in one direction.

  2. Too many tags. This may be a matter of personal taste, but what's the point of adding oneway=no, bicycle=yes, foot=yes, cycleway=no, access=yes, motor_vehicle=yes to every street? (And sometimes people will think they have to fill in every value despite not knowing for sure what they are, leading to bicycle=no on major highways where cycling is actually legally allowed.) Related is the misuse of the designation tag, which, according to the wiki, is only for certain types of object in the UK, but has been incorrectly used for what belongs in name, ref, note, or other tags.

  3. Use of separators other than semicolons. The accepted way of tagging an overlap of two routes is with a semicolon; e.g. ref=I 80;I 90 for the long segment of toll road that carries Interstates 80 and 90 together. But PL2 displays this as red with a warning icon - "This tag contains more than one value - please check" - leading some mappers to "correct" the tag with a slash, dash, comma, or by deleting the second route.

Comment from Pieren on 5 September 2012 at 09:49

yeah, the invalid usage of "designation" is a growing issue. In France, we have now more than 3000 elements with the incorrect tag, most of the time created by newcomers who do not understand the meaning of the field in P2. I'm really surprised that it has been reported 6 months ago on trac and nothing has been done to fix this although P2 is almost always the first editor used by newcomers (and many times, the only one). The only answer I received until now was "develop a patch yourself". Sad.

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Comment from Chaos99 on 5 September 2012 at 12:51

at 3. Thought the 'accepted way of tagging [..] routes' was with relations, not tags. (Exactly because they could overlap.) And that 'tags containing more than one value' were actually not recommended at all. (Regardless of the separator used.)

But maybe that's just like the German community is handling it. Could at least explain why potlatch behaves this way.

Regards, Chaos

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Comment from Peter Dobratz on 5 September 2012 at 13:05

I'm also finding that some new mappers who don't know about the advanced mode end up trying to shoehorn existing objects into things that P2 simple mode recognizes. In spite of the warning "Try looking at the tags under the advanced properties", they end up clicking the unknown drop-down and then picking something. Then we get things like natural=wetland changed to natural=water and landuse=landfill changed to landuse=industrial.

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Comment from Richard on 5 September 2012 at 22:26

@Pieren: did you not read my reply to you at http://lists.openstreetmap.org/pipermail/tagging/2012-August/011226.html ? In that when you say "nothing has been done to fix this"... I actually fixed it?

Still waiting for you to forward the Cadastre details. Which is closer to 6 years than 6 months. No hurry, mind.

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Comment from Pieren on 6 September 2012 at 10:05

Okay, I just noticed the recent changes in P2 presets after that post (sorry, I'm not using Potlatch daily). About cadastre details, I already replied to that request in the past. Nothing new. And here is not the right place to discuss it again. We can do this privately.

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Comment from joakimfors on 11 September 2012 at 17:59

… also, P2 shouldn't allow any editing until all data in an area has loaded.

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