Mysterious green dots in Potlach

General talk
1

Question from a complete beginner:

When editing I occasionally run into a region with very many green dots, with no apparent information attached to them. For example, going to this map, then clicking edit, I see very many dots around the pond and to its SE. Since they do not seem to render in the map, they seem pretty harmless, and they no longer even irritate me :slight_smile: But I am curious; what are they and where do they come from?

Many thanks!

2

They are just untagged nodes that are not part of any ways or relations. As for why they are there, I’m not sure.
Checking the history, it looks like most of the ones in that area were created by user assawyer. Specifically, in these 2 changesets:
http://www.openstreetmap.org/browse/changeset/1334709
http://www.openstreetmap.org/browse/changeset/3283766

I suspect they were parts of ways which were deleted, but the nodes left behind for some reason. Or they were doing some sort of import, but only imported the nodes and not the ways they should be part of.
Probably worth sending a message to that user, and asking what they were doing, and how it could be fixed.

3

It’s an annoying Potlatch bug, and not completely harmless: http://trac.openstreetmap.org/ticket/2700
assawyer is simply the person who created the nodes as parts of ways, and later the ways were modified and left the nodes behind. More likely than not, they were created as part of a mass import (often TIGER streets).
If you download the area in JOSM and run the validator plugin, you can mass-delete “untagged unconnected nodes”.

4

It happened to me with Potlatch too. Uploaded a .gpx track and then removed part of the track. The nodes of that part became -green- poi’s.

5

These dots can be caused by any one of a number of means (it is not specifically a Potlatch bug), but usually they are:

  1. The result of an aborted upload. The nodes were loaded, but the ways were not. As the ways have the tags the imported nodes remain tagless. This is probably the most frequent cause, and they are most common in areas where large volumes of data have been imported (for instance in the US, National Hydrography Data (NHD)). Uploads may be aborted by the user, by failed connections, violation of some condition etc.

  2. The result of a partial deletion. Again the way is deleted, but not its nodes. This certainly happens in Potlatch, but also in Josm (for instance using Validator to remove duplicate ways). In Potlatch I think it is usually a failure in the server communicating back that the request has not been served.

These nodes are a pain, the current duplicate nodes project (see http://matt.dev.openstreetmap.org/dupe_nodes/about.html)) is aiming to remove as many of these and other causes of duplicate nodes over the next few weeks. With a JOSM download of an area, and using validator it is easy to safely remove these nodes, but do not just fix all duplicate nodes: you may be joining roads to powerlines, pipes, railways and city limits!

SK53

6

Nope - it happens consistently if you follow the instructions in http://trac.openstreetmap.org/ticket/2700 - not a connection problem.