OpenStreetMap

The consequences of paths not being rendered fully...

Posted by wallclimber21 on 9 August 2009 in English (English)

I already filed a request for this with CloudMade about a month ago, but I just want to stress the importance of rendering ways that are marked as 'path' in full.

Right now, in the best case, tiles render the path but they don't render the path name. (OpenCycleMap renders the path name, but not the path itself, go figure.) In the worst case, unfortunately the default CloudMade tiles, paths are not rendered at all.

This makes the Cloudmade tiles very much unusable for all the mobile apps that are targetting hikers and bikers.

The goal of OSM is to create an all encompassing free maps database, but, let's be honest, when I'm in an urban environment, I'll use Google Maps, because that's what's all iPhone apps use and because it's information is complete enough. In my opinion, the real practical value for OSM is for those roads/trails/paths that are not covered by Google Maps. When I started with OSM in november last year, pretty much all open space preserve parks in the SF Bay Area were empty. I've added many hunderds of fire roads and single track trails everywhere and other have done the same. When you go there now to very popular parks for mountain bikers and hikers, a lot of them are now trail complete. It's exhilarating and something where Google Maps (and it's competitors) are absolutely nowhere.

For a mountain biker and a hiker, it's important to know if a trail is a single track or a fire road. We love the first and loath the latter. A single track is marked as 'path', a fire road is marked 'track'. I spend a lot of time annotating them correctly.

But in the last weeks, I've seen two cases where trails that I've added were changed from 'path' to 'track'. I sent a friendly email to the one who changed it. They were enthusiastic beginners at OSM who made the change because it would make a trail show up on CloudMade or OCM tiles. I can educate new users all I want about not tagging feature with the renderer in mind, but, think about it: it's pure coincidence that I stumbled into these modifications: they were in parks that were just a mile from my house. I don't know how many other incorrect modifications have been done because of this. All those changes are doing with the best intent: to make their features of interest show up on the map. Who can blame them?

(Maybe OSM needs some kind of change notification system, where interested parties get an email when something in a region of their interest has been changed?)

So, please, CloudMade, fix this. It would make a whole bunch of my iPhone map applications much more useful and will prevent people from making incorrect changes to the database.

Stepping off my soap box...

Comment from wallclimber21 on 9 August 2009 at 19:21

(Yeah, I used "it's" twice where it should have been "its". Should reread more carefully before hitting 'publish'.)

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Comment from dmuecke on 9 August 2009 at 19:43

I regularly run a difference report on my area with http://wiki.openstreetmap.org/wiki/Osmdiff. I guess that could be useful in your case. If you need assistance let me know.

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Comment from Philip on 9 August 2009 at 19:47

It would seem logical to render all physical ways (at a zoom level 11 and above) - only the width and detail of the line should change as you zoom in. By zoom level 14 or 15, all barriers (gates, stiles etc) should be rendered.

Maps which do not render all physical ways and barriers across those ways should be clearly marked as 'specialized'. This doesn't just apply to bikers and walkers, but to any user of any way (roads, trails, rivers etc). The 'cluttering' effect can be minimized by clever used of light colour tones.

I'm trying to map as many of the rights of ways in my corner of the world for a trail plotting app, but will end up downloading planet.osm just to get useful rendering (e.g. mapnik and osmarender don't show barriers half the time).

I know this is the whole idea of OSM (freeing the data), but I'd like to see this debate opened up.

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Comment from wallclimber21 on 9 August 2009 at 19:55

The Osmdiff example of Hessen is pretty awesome. :-)

I'm not sure if it would be immediately useful though: I tend to have pet peeve project (e.g. correctly align all TIGER data for the city of Fresno) then switch to adding all fire roads of Mt. Diablo Park, then add all new streets in some backwater town where I've never been. My edits are all over the state of CA...

But it could be a first start to at least monitor some places of interest. I've been setting up a Postgis database with OSM data for a different project. Will take a look at Osmdiff.

As for the comment by Philip: I have the impression that the OSM main page renders pretty much everything, including those almost useless administrative boundaries that were imported for the US. Indeed, I prefer that much more over the arbitrary non-rendering of data that's really useful for some people.

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Comment from Minh Nguyen on 9 August 2009 at 21:41

ITO World’s free OSM Mapper service might have the kind of filtering you want, but it sometimes lags behind a few days at a time.

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Comment from smsm1 on 10 August 2009 at 14:00

A path is a single groove worn by lots of walkers, in general you don't want to walk along them as they will often be muddy or difficult to pass. You should look to using highway=bridleway, cycleway or footway before even thinking about highway=path. You might be interested in the Style Editor.

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Comment from wallclimber21 on 10 August 2009 at 15:42

> A path is a single groove worn by lots of walkers, in general you don't want to walk along them as they will often be muddy or difficult to pass. You should look to using highway=bridleway, cycleway or footway before even thinking about highway=path. You might be interested in the Style Editor.

This is absolutely not obvious from the Wiki Features page and from the discussions in the forums.

A footway, as shown in the wiki, is more like a 'road' but for pedestrians only. Usually in an urban setting and usually paved. It would be wrong to tag a small mountain trail as a footway: you're basically classifying entirely different things under the same name.

The cycleway on the wiki is the same story as footway. Something that's rideable by a regular bicycle.

The bridle way on the wiki looks very much like a fire road. Much wider. Note that it also says that it's equivalent to 'path + horse=designated', which suggests that marking it as such is equally valid.

Basically, the tags that you list suggest a structured, planned, usually urban, often paved ways. And, in fact, your message confirmed that the trails are correctly marked as path: a muddly groove that's often difficult to pass in park. Yeah, that's exactly how I wanted them marked. It's what mountain bikers are looking for, except that they're not muddy in California. :-) )

And I'ved looked at the style editor (and filed a bug request with Cloudmade): the best it can do, is mark show the paths, but there's no option to also render its name. Which makes it pretty much useless for hiking/biking purposes.

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Comment from dmuecke on 10 August 2009 at 18:38

Regarding osmdiff. In order to diff only your area try folowing
1. create a polygon file from your area
2. download from from planet.osm that file that covers your work
3.Extract your area via osmosis like my example below
osmosis --read-xml file="baden-wuerttemberg.osm.bz2" --bounding-polygon file="hohenlohe.poly" --write-xml file="hohenlohe_07.osm"

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Comment from Frankl2009 on 11 August 2009 at 01:38

Yes, I would also VERY much appreciate it if I could use the CloudMade editor to get walking paths etc. and indeed all the other stuff which is useful for walkers onto the maps.

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