I can compare Ecuador, Peru, Bolivia, Argentina and Chile from driving around there. I would say Argentina and Chile both have great maps, especially when it comes to completeness. But Argentina might be a more interesting case for you, as I think they didn’t have a large import. Ecuador is also pretty good. Peru and Bolivia have a lot of work left.

Sander, I can understand the fear which might be very reasonable in some cases. The situation in Bolivia comes to mind, where we can make “formal” decisions if we agree among two or three people.

But I don’t think there’s anything to worry about in this case. This mapper’s interest is first and foremost landuse mapping. So yes, his view of landuse mapping will have a serious dominance in Flanders. But in this case, that’s a good thing, because he did a terrific job. So while it is a big lot of nodes, it’s only a quite narrow theme that he is dominant in.

The other thing about landuse is that it’s pretty stable. Mapping a few 100 square kilometers takes many many hours. But keeping it up to date is a completely different job, and a lot let labour intensive.

Hi Martin,

This is a slightly more elaborate answer than what I expected :)

Here’s some thoughts: - the longer term retention is worth keeping an eye on as numbers increase, keeping in mind selection and social effects of course - are you sure the difference in labour hours at the events is real and not an artifact of the way JOSM and iD save information to the database? For example, if you take the difference between first and last object saved as labour time, that might affect JOSM negatively. Did you (or could you try) look at the last save during an event minus the start time of the event? Probably difficult on a larger scale, but might be worth a check at a single event. - you filtered away the people who used both editors. It might be interesting to see if they started off using JOSM and gave up to fall back to iD or if they took the other way around. If it looks like the former, one can imagine more people giving up before having anything worth saving.

Thanks again. We’ll think about how we can experiment more at our events in Belgium.

Link kaput, and you can’t edit your comments. Hope this works: http://imgur.com/2hxAXNk

From what I understand, you look at the shape of the growth curve of the road network. The visual inspection is just a crosscheck. Here’s an example of the curve I’m guessing you use, from Flanders, Belgium.

As you see growth flatten out over the years, you can make the assumption that the road network is “complete” in the sense of having the geometry of almost all roads.

A couple of things to keep in mind:

• this only holds true if the community is large enough. Growth will also peter out if there are not enough good sat pics left to map or no more people willing to map. I just wrote in my diary about how even in a large community like Flanders, 44% of all nodes were mapped by just one guy. Now imagine how things might go in a place like Bolivia. It might show up in the data as a certain shakiness of the graph, but you do have a number for all countries.

• as you can see in my example, one road isn’t the other. in Flanders, the growth curve for main roads (tertiary and up) is quite similar to the minor roads (road, unclassified, residential, living street). But that might not always hold. For example, in Africa, a correction of tagging might distort numbers when a lot of tracks suddenly become main roads.

• I used the Chile map in real life. I don’t think I found any road at all that was missing there. But that brings me to something else: imports (as Chile did). They obviously distort the curve. I would imagine that the road network in the US also looks quite “complete” since many years, as the huge Tiger cleaning operation won’t have much effect on overal network length. Completeness does no necessarily implicate quality; making the measure most useful in countries without a large import.

I’d be very interested to hear more on how you went about this analysis.

I just did some calculations for Belgium based on the history files. I have 8900 contributors by january 2015 (I know, I should get some fresh data). You got to 7622 on more recent data. I think that’s pretty decent, a similar order of difference you get in these comparisons, like I checked here for Brasilia.

So to second Warin: don’t just “correct wrong tagging”, but get involved in local road tagging discussions. Otherwise you run the risk of getting your work reverted.

The Highway Tag Africa is highly relevant, however it does not talk about freeways. If there is any type of road we could agree on at a global level, it should be freeways. There is a simple list of physical properties that you can use to decide if it is a freeway or not.

For all other road levels this is much more complex. The African scheme takes into account only economic/practical importance measures, but in countries like Peru and Argentina the government classification has final say.

That makes a lot of sense. I too learned how to map things mostly by looking at how other people mapped similar things, long before I knew my way to places like wiki and mailing lists.

Thanks for sharing.

Segun esta pagina wiki, el “name” es para el nombre oficial. El nombre tradicional, se sugiere ponerlo en name_alt.

So Seattle has a 3.5 million population and 400 Meetup members. Belgium has 10 million and 133. Do you have an especially thriving local community or is the cliché of the USA not having many mappers simply not true?

@StephaneP j’ai répondu sur ton blog, en englais.

My wife had a good laugh with your comment :)

@phillippec , true, I might increase picture frequency in the future. And of course wider angle would be better. Do you have any experience with dashcam footage for mapillary? I wonder what it looks like within their platform.

Nope, just a group of hobbyists. The one in front had the accident. As they were stuck waiting for police they covered their cars to protect from the fresh salt on the road.

Completely correct to undelete, but I do recognize the dilemma. I see no simple solutions.

En mi auto funciona bastante bien con el soporte de Mapillary. Depende un poco de como lo pongo; al inicio pusé la camara lo mas lejos posible del soporte, y ahi si da vibracion. Pero me di cuenta que salen bien las fotos igual cuando esta mas al medio el telefono.

To add to naoliv, what to do when you stumble upon an area where existing elements do not align current sat pic? The best is of course to align old and new elements correctly. But if there are no (or not enough) GPX traces available, it might be best to shift the sat pic according to the old data. Maybe previous mappers had something more to work on, like private gps tracks. If you’re convinced the new picture is better, it’s probably easier to adjust all existing elements first, and only then start mapping new things. Of course, the worst option is to ignore the problem, and have different adjustment for old and new stuff. I kind of messed things up like that in El Alto, Bolivia when I added huge suburbs; it’ll be quite some work to fix that up.

I also like mapping like that. Just tracing roads on an empty canvas. The corner of the world I keep finding myself is around Coroico, Bolivia. Recently, I’ve been improving the huge woods there, still picking up some missing roads and hamlets there. After a while, you start noticing other people improving on your work - that is the most fun of the whole thing.

Yes, governments like their shapefiles. One “shapefile” is composed at least of a shp, shx and dbf file. The dbf contains the attributes (things like names etc.), the shp file contains the actual geometry. Free software like QGIS and expensive software like ArcGIS combine these into pretty maps. If you load the files into QGIS, it will probably make it easier to find what data has a copy in OSM.

I would expect admin areas to be relations forming a polygon (a closed line) in OSM. However, this random place has a closed line for a border: osm.org/way/33104058 (Relations allow several admin areas to contain the same lines as building parts. That means less data and easier editing: if you correct the border, all admin areas using that border are fixed) Maybe one of the several tiger:… contains an ID field you can use. The OSM id is pretty random, that you can basically ignore.

This doesn’t seem to be in OSM yet, right? If it were, here’s how you’d get the members out of Overpass Turbo: http://overpass-turbo.eu/s/b7I

I think the editing you want to do, can easily be done in the old standard editor Potlatch2. See osm.wiki/Potlatch_2/relations .

If you need an editor for just editing tags, as said above, Level0 could be it; Here’s my experience of using Level0 to work on some stuff collected with Overpass-Turbo: osm.org/user/joost%20schouppe/diary/35194

If governement is to use this data, they will need to do quality checking that’s for sure. Admin areas are OFTEN damaged by uncareful mappers.