I have a memory of OSM copying the Wikipedia motto "be bold". However, I've noticed the USA mailing list errs on the side of "be accurate". In particular, it seems like proposals to automate the correcting data are typically declined in favor of human review. Now, I'm not suggesting we turn OSM into "bots gone wild", but is it realistic to expect all problems to be fixed by hand?

What does being bold mean to you?

I've been spending a lot of time fixing problems reported by this web site in Minneapolis, of all places. I'd say the most common TIGER import problem is unconnected ways, which no doubt makes routing problematic. I'd also say the most common human introduced problem is unconnected ways, particularly when splitting a single way into two oneway streets.

You owe it to yourself to take a look at where you've been editing from this site. You'd be surprised how many little mistakes might appear.

I've been cleaning up a bunch of maplint reported by Keepright, http://keepright.ipax.at/, which rocks!

(All comments based on USA data.)

Unfortunately, I'm starting to get to the conclusion that routing OSM data just won't work for any road smaller than highway=tertiary. It seems that the TIGER import didn't connect a bunch of roads near county lines that are away from the cities. That's not too hard to fix if mappers spend some effort.

There is also a fair amount of bad data due to edits. For example, streets are split into parallel one-way roads, but the new road doesn't get an intersection at every road it crosses. Or the new driveway almost touches the main road.

The trouble is things look good in the web. Intersections are rendered the same as non-intersecting roads. Visually, the map is good enough. However, from a routing perspective, the roads never meet, so you'll never get to make that right turn. This is going to be a serious problem for anyone who wants to use OSM data for routing. Without going to external websites, the map appears just fine, possibly leading to more incomplete edits.

Until this data gets beat into submission, I think OSM maps are going to be good for printing and viewing but risky for door-to-door routing.

So how important is routing?

One of the great things about using a wiki is you can make corrections. Unfortunately, I feel like I'm seeing more corrections for corrections sake. For example, Portland has two stadiums, the Memorial Coliseum and its replacement the Rose Garden Arena. Someone decided the latter needed a building=yes tag and now it looks like any other building:
osm.org/?lat=45.53191&lon=-122.66807&zoom=17&layers=B000FTF

Plus we can't seem to agree whether walkways in a park are tagged as
highway=path
osm.org/?lat=45.49989&lon=-122.84522&zoom=16&layers=B000FTF

highway=cycleway
osm.org/?lat=45.45742&lon=-122.79547&zoom=17&layers=B000FTF

highway=footway
osm.org/?lat=45.43966&lon=-122.68015&zoom=17&layers=B000FTF

or highway=track
osm.org/?lat=45.49377&lon=-122.68872&zoom=17&layers=B000FTF

These ways keep getting tagged and tagged again. Meanwhile, we have neighborhoods without street names
osm.org/?lat=45.55209&lon=-122.80814&zoom=17&layers=B000FTF
and retail areas with no POI
osm.org/?lat=45.55209&lon=-122.80814&zoom=17&layers=B000FTF

Maybe this has to do with the fast-and-loose approach to tagging. I mean, there is a valid a case that a sidewalk is a path, paved/unpaved, a footway and a cycleway. The problem as I see it is these changes don't make the map better, just different. Perhaps when tagging stabilizes we can make a bulk edit.

It seems like there are enough TIGER fixes, new roads, trails without traces, missing bridges, POI and other details that changing tags of existing features is perhaps not the best use of time.

UPDATE:
What I'm really trying to say is that instead of changing the tags on something that's already mapped, add new data instead.

The leisure=stadium tag implies building=yes/stadium/multi_storey/.... Otherwise, the thing is a pitch.

Don't believe me? The Memorial Coliseum and the Rose Garden Arena are both stadiums. As of 12-mar-2010, someone has decided that the Rose Garden Arena also needs an explicit building= tag. See the difference yourself.

osm.org/?lat=45.531731&lon=-122.667919&zoom=18&layers=B000FTF

Interestingly, there are some facilities that need the building= tag to render. For example, a bus station renders but a train station won't. Compare Union Station to Grayhound. (Well, or you could but the railway=station tag has been removed from Union Station, sigh.)

osm.org/?lat=45.528022&lon=-122.676062&zoom=18&layers=B000FTF

Why have all of the secondary roads been disappearing in Portland, Oregon? It looks like someone has decided that only highways (e.g. roads that have a ref=) get to be secondary roads.

It seems like there should be a distinction between two and four lane roads. Looking at the current map, you have to guess the major streets. What's the point in that?

I can assure you that SE Hawthorne is more busy than SE Harrison. osm.org/?lat=45.5108&lon=-122.63488&zoom=16&layers=B000FTF

I've taken to skiing and have been trying to map the runs at beautiful Timberline Lodge on Mt. Hood, Oregon. You can view the results on openpistemap.org or OSM, with the osmarender.

Renderer complaints:
It would be nice if openpistemap actually rendered the recommended piste:name tag.
It would be real nice if it was smart enough to give the runs the colors we use in the USA (green, blue, black).
It would be nice if osmarender put the chairlift names (and chairs) consistently. Why is Molly's the only lift with a different orientation?

I've been spending perhaps too much time fixing problems identified by http://keepright.ipax.at/. For reasons I don't understand, the USA TIGER import seems to have more problems of certain types in certain areas. For example, a lot of roads in Washington state seem to have layer tags for no apparent reason.

It would be nice if there was a way to correct more than one problem at a time, as loading Potlatch for each change is slow. I'm using a G5 Mac, so I can't use its JOSM option...right? This would be particularly useful for making changes like joining roads that are split across county lines.

I've spent a lot of time adding bridges to the map.

Bridges are important map features since
* They help with routing because it's clear that roads don't intersect.
* They give an idea of how the land appears.
* They explain why there aren't more connections between roads.

That said, I've learned a few things about bridges in OSM.

They are somewhat unusual in they take two tags, bridge=yes and layer=N, where N is 1-5. At first, I thought this was redundant, going as far as to remove layer=1 tags. After all, a bridge implies a higher layer. However, that's not how OSM works.

The layer tag isn't always important for Mapnik to render a good looking map. It seems to understand that a bridge goes above other ways. However, Osmarender needs that layer=1 tag because it gives a priority to each highway= tag. So, for example, a highway=tertiary,bridge=yes way is overwritten by a highway=motorway way. Adding the layer=1 tag to the bridge makes it render properly in both renderers.

So view your favorite area with Osmarender and look for bogus bridges.

There are a bunch of symbols that are now rendered but don't appear on the Map Features page, for example, cave entrance. I see they reference image files but it's not clear to me where those files are and how they got there. If you can give me a pointer I'll update a bunch of them.

There has been some buzz about Google now supplying their own data for Google Maps. Maybe now we see why they were doing all of the "Street View" stuff.

Anyway, this brings a big opportunity for OSM. New neighborhoods (that I am familiar with) seem to have a ton of mistakes: alleys are streets, names are wrong, etc. It sounds like Google is more responsive about getting these things fixed. Maybe if I'd started mapping about now, I'd have been content letting them know about their mistakes. But the opportunity is to get people making the changes to OSM instead of the GOOG. Why get their approval when you know you're correct? And who benefits anyway?

Ditto with their Map Maker tool (which doesn't work in the USA). Why are people spending time creating data where they relinquish the rights? Maybe Google Maps is the big thing, but what else is gained other than advertising all over your map? I mean, if there is no data in, say, Mozambique (and I have no idea whether there is or not), why give it away to a proprietary provider?

Plus, OSM allows for a much richer view of the world, particularly if you're not in a car.

The consensus is Google won search because they have the best results. Look at your favorite area and ask yourself whether that is true for maps.

I've added a lot of highway=turning_circle (originally this said traffic_circle, oops),source=Yahoo tags with Potlatch. The r (repeat) key is a real timesaver here (except there seems to be a bug where sometimes every tag from a node is repeated, not good if it has TIGER data).

That said, I just realized there was a better way to do this with JOSM. Shift-select all of the turning circles, and add the tag just once.

Now if only the JOSM imagery was as good as Potlatch....

When I started contributing to OSM, my favorite uploads were new roads that did not appear on the map and adding bike lanes. Then I started fixing mistakes in the TIGER import and adding POIs. However, there must be something about doing this over time that makes one want to add more and more details. While I first thought tagging traffic signals and speed bumps were too much detail, I'm now inclined to do it as time allows. Anyone else fall victim to this behavior?

Who knew there would be so many ways to park a car? The renderers are finally catching up. We have the basic amenity=parking and the exciting additional key parking=multi_storey for parking garages. Osmrenderer is also adding a special icon when you tag with fee=yes.

I'm not totally sure how to map a mixed use structure, for example, one that has storefronts on ground level and parking up above. Maybe buildings aren't the best for simple tags.

OK, I know we're not supposed to tag just for a renderer, but Mapnik is now rendering traffic lights and water towers. So now you have a reason to add those tags, if you've been holding back. Go nuts. :)

OSM has also added different viewing options for traces.

It would be nice to see a notification of changes in advance (without having to read through mail lists).

I'm really curious as to how anyone has found my diary entries. In my brief experience, the only way to view them is a RSS feed for the entire OSM world...in everyone's native language. How do you find interesting entries?

I wonder whether it would be possible to do a bulk update of man_made=lighthouse based on locations in Wikipedia....

From an email:

I've typically been trying to mark paved paths has highway=footway, unpaved walking paths as highway=path and signed bike lanes as highway=cycleway. If I'm feeling extra energetic, I'll also tag with bicycle=yes/no, and so on. My inspiration is the pictures on the OSM wiki, osm.wiki/Map_Features#Highway, particularly osm.wiki/Tag:highway%3Dpath and osm.wiki/Tag:highway%3Dfootway.

Any others in Oregon agree with me?

I see Mapnik now renders highway=unsurfaced and highway=raceway. (Update 1-aug-2009: corrected tags.)

The former works out pretty well since I often want to know whether I can ride my road bike on it. I think of highway=track as a dirt road.

The latter isn't really all that important, but it helped me with Portland International Raceway. Initially, I took a look at either Hockenheim or the Nurbringring. They had the track labelled access=permissive and oneway=yes. It kind of made sense, although it seemed like it could also be access=private. That said, a separate tag for a racetrack just feels like a better solution.

My initial edits to OSM were to tag highway=tertiary for the roads in Portland, Oregon, USA. I've used a pretty simple formula: if the road has a dividing stripe and it is tagged as highway=residential, change it to highway=tertiary.

This works pretty well in the city. However, it starts to fail out of town, since country roads typically are either gravel or have a center line. Aesthetically, I'm not sure I like seeing remote areas where every road is tertiary. Maybe I'll do some tagging in a rural area and see how it looks.