I'm interested in identifying the most common mapping errors you stumble upon from other OSMers (or that you make yourself).
If we could list some of the most common mistakes then we could use that information to drive improvements that may help to prevent the same mistakes being made in the future (e.g. by clarifying the wiki documentation, modifying the editor UI, writing scripts to find the mistakes etc).
This is obviously a very subjective question, but hopefully some people may find the answers useful. Please try to stick to definite actual errors, rather than simple differences of opinion.
This question is marked "community wiki".
asked 06 Oct '10, 15:01
Not being explicit with topology. E.g. intersections / junctions are often not mapped in a way that makes it clear which way is the one discharged into the other (they seem equally important from the mapping, the form of the junction is not mapped). Topology is also a matter when it comes to the limitations of GPS accuracy: some users tend to believe the GPS unit more than their eyes: they map a feature on the other side of a road if the stored coordinates of the waypoint indicate this. Or they draw zigzig-lines where the road is perfectly straight.
Combine two highways because they have the same name, ...
but the two ways actually have different tags or are not both members of the same relation.
answered 14 Aug '12, 18:42
The opposite is the use of highway=cycleway for ways sharing both cyclists and pedestrians, hence needing either an additional foot=yes or just highway=path (and optionally foot=designated and bicycle=designated depending on the actual purpose).
These mistakes are quite common. Also see the wiki on access restrictions on different kinds of ways. They may differ from country to country.
For mistakes like unconnected ways, there exist several quality assurance tools such as keep right which report ways that are very close to each other, but unconnected, as well as many other common mistakes.
But... there must be a standard?
First timers often think that there is one right way to do stuff, or that everyone maps everything in the same way, this is not the case. We strive to make things simpler, but there really is no way to make thousands of people map the same way, so there is always going to be more than one way to do it.
Thinking that ways that are part of $longdistanceroute are actually called $longdistanceroute
In the UK at least, this usually isn't the case. I suspect that new mappers do it to get the name to appear on the main OSM Mapnik map, or because they haven't yet figured out how relations work.
answered 05 Sep '11, 11:07
In JOSM I once made the mistake of downloading an area then subsequently editing outside that area, without realising it was outside the extents of my downloaded region. So I ended up adding objects that were already there, but I didn't see them as I hadn't downloaded that area. I quickly found "Draw boundaries of download data" under the Preferences>Display>OSM Data and turned it on. No more of such problems. I think that from a usability point of view, it should be enabled by default.
Using search-and-replace to do small 'mass edits'
New users tend to use the search-and-replace function of editors to do 'corrections' to a massive amount of nodes or ways in their area when they believe they found an 'error' of some kind.
Not mentioning here if the 'error' really is one or not (new users might have trouble understanding all the tagging schemes used in OSM), the mere application of such changes in an automated manner often destroys more valuable data than it fixes. This is also regularly used to fill in perceived "blanks", even if those blanks are left intentionally or are coverde by some kind of default.
This is often combined with the "leave no changeset comment" problem already mentioned.
answered 19 Aug '13, 16:02
In Africa highway mapping, track only goes to farmland.
So ruled in Highway_Tag_Africa.
"The road conditions in African countries do not always correspond to their economic and social role. A road typology should be based on the road importance and not on the surface or the visual appearance of a road."
This means, it may look like a track but, if it goes from a major road to a hamlet, it's an unclassified highway, except a 4x4 can't drive it because it wiggles too much (then it's a path). Ditto from hamlet to hamlet.
People new to Africa mapping always get this wrong.
answered 13 Dec '14, 14:51
From potlatch (users) I often have to fix self intersecting ways. Mostly this is a way going back again or making a small loop on itself before it ends or goes on. Not sure if this is a bug in Potlatch or if the users don't use it correctly.
At 348 km ways with 39.8 k nodes I had to clear ~90 of this errors.
answered 24 Nov '12, 15:35
Confusion between "Common Name" and "Operator" of a POI
For example, take a Citibank ATM.
Another example: A Dominos pizza joint. Legally, "Dominos" is the brand, operated by a local franchisee (a separate business entity). So how to fill these attributes?
As a result, I have seen inconsistent entries in POIs.
Suggested solution: The mapping tools (iD/Potlatch) should have more explicit tooltips.
answered 13 Mar '15, 07:03