Re: [Tagging] Waterway river vs stream
On Sat, Oct 19, 2013 at 11:03 AM, Christoph Hormann chris_horm...@gmx.dewrote: As far as verifiability is concerned - it seems the question how far an able person can jump is not an issue here. As i said before i would interpret the rule from a practical standpoint, i.e. tag as stream if i generally would assume crossing this waterway with dry feet would be considered feasible on a hike by most people without disabilities By that standard, a few hundred miles of the Arkansas River at normal stage would be a stream, including nearly everything from the Zink Weir downtown to where the Verdigris River meets the Arkansas near Muskogee. That's just silly. ___ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
Re: [Tagging] Waterway river vs stream
On Monday 21 October 2013, Tyrfing OSM wrote: Yes, changing the definition of a tag is a problem. Like Kytömaa points out it seems like the jumping distinction has become stricter during the years: Maybe you can just jump over it (2007), An active person should be able to jump over it (2009), an active, able-bodied person is able to jump over it (2013). This is probably due to the increased awareness among mappers that verfiability of the tagging is of fundamental importance. The verifiability page (http://wiki.openstreetmap.org/wiki/Verifiability) has been initially created in 2009. Also it seems like different people has interpreted the distinction between river and stream differently. At least according to posts in this thread. So I'm not too sure that the data already in the database is coded consistently according to your interpretion. Probably not - and more importantly there are tons of data from imports with no informed decision on river vs. stream for the individual way at all. This does not mean of course that there is no value in keeping this information in the database, especially if for the future there is a clearly verifiable rule. Something like crossable=* might be a good idea. Also some sort of tag for amount of water flow might be an idea (like waterflow=high/low/42 m^3 /s). Practically this will be next to impossible to determine except at a measurement station where it would make more sense to tag the node. If someone has an idea for a practically measurable quantity that has a clear relation to the discharge of a river that would be useful to tag of course. Greetings, -- Christoph Hormann http://www.imagico.de/ ___ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
Re: [Tagging] Waterway river vs stream.
Using if an able person can jump it as the rule has some issues. How far Not only that, but as it was described years back* (Maybe you can just jump over it. from January 2008) did not seem like a hard set rule, but like a soft description. * http://wiki.openstreetmap.org/w/index.php?title=Tag:waterway%3Dstreamoldid=69266 That's how I read it, and I'd be inclined to believe that's how many who don't speak English as their native language would read it: - If you can jump over it, it's probably a stream, but not necessarily - If you can't jump over it, it's more likely a river, but it might still be a stream - Locally prevalent mindset will have an effect on where the line between a river and a stream is set. Around here most, if not all, people would never call many of the non-jumpable streams and ditches rivers, so they would not know to tag them as rivers. A trunk road is bigger than a residential. A river is bigger than a stream. Yet: a trunk road in rural areas may be 1+1 lanes 9 meters, but a residential road elsewhere may be 2+2 lanes and 13 meters plus sidewalks. Likewise: a river in one part of the world may be narrower than a stream elsewhere. When we can't rely on somebody else's authority (e.g. ref for highways), the classification always has some gray areas where local practices use a mixture of locally important attributes to move the line one way or the other. My point being, that these top level classifications with only two categories hardly make sense for globally valid hard set division by one attribute. If somebody has the means and resources to survey and to tag the width and jumpability and mean annual flow and all that, they will come along and add that later. Being a stream in OSM doesn't even tell us with great detail how big it is; a small stream is something you can step over - or even bike over - and a bigger stream might be unjumpable. Is that jumping measured with sneakers and without baggage, or with a backbag filled with a weeks food rations? And which one makes sense as the dividing line for a general use mapping database? * Was three with waterway=riverbank, but even that has been diluted in this meaning as mappers have had time to draw even narrower rivers with the riverbanks. -- alv ___ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
Re: [Tagging] Waterway river vs stream. Was [Imports] [NUUG kart] kartverket imports to OpenStreetMap
2013/10/19 Tyrfing tyrfing...@gmail.com Using if an able person can jump it as the rule has some issues. +1, it also depends heavily on the surroundings (surface, steepness, solidity of the riverbank, ...) if you can effective jump over it, just a small width doesn't tell you anything if this is a barrier to a hiker or not. cheers, Martin ___ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
Re: [Tagging] Waterway river vs stream. Was [Imports] [NUUG kart] kartverket imports to OpenStreetMap
On 19.10.2013 14:58, Martin Koppenhoefer wrote: 2013/10/19 Tyrfing tyrfing...@gmail.com mailto:tyrfing...@gmail.com Using if an able person can jump it as the rule has some issues. +1, it also depends heavily on the surroundings (surface, steepness, solidity of the riverbank, ...) if you can effective jump over it, just a small width doesn't tell you anything if this is a barrier to a hiker or not. by no doubt the distinction is a problem and width does not work. Best would be the volume on averaged water flow. I wonder why we do not have waterway=stem though. But this does not change the fact that either the river is the result of some other waterways, fed by some water body (water=*,glacier) or it will start as something smaller than river. At least in the last case a relation might be useful. Cheers fly ___ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
Re: [Tagging] Waterway river vs stream
I think the whole issue should be split into two separate questions: The verifiability of the rule and the rule itself. As far as verifiability is concerned - it seems the question how far an able person can jump is not an issue here. As i said before i would interpret the rule from a practical standpoint, i.e. tag as stream if i generally would assume crossing this waterway with dry feet would be considered feasible on a hike by most people without disabilities. Of course there will be borderline cases but there always are, even if a quantative rule exists. The question of changing width of a waterway can also be answered from a practical perspective - it is sufficient for the waterway to have occasional points where it can be crossed to qualify. This interpretation of course also means that the tagging of a waterway does not only depend on the properties of the waterway itself - a 1 meter wide 'stream' running in a steep walled gorge 10 meter wide on top cannot practically be jumped across. Which leads me to the rule itself which - as noted previously - does not make much sense as a mandatory top level distinction for waterways. But it has been around for a long time and a lot of data has been tagged based on it. This in my opinion means changing the meaning of the existing river/stream distinction - even if there was a practically verifiable alternative rule - would serve no purpose except devaluing existing data as well as newly entered information. The only sensible way to change things would be to move the distinction into a secondary tag (something like crossable=* for example, that would also allow tagging the possibility to wade through) and to re-tag all waterways with a uniform primary tag (natural=waterway would be an obvious choice although it could be useful to make the distinction natural/artificial waterway indeed mandatory). Greetings, -- Christoph Hormann http://www.imagico.de/ ___ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
Re: [Tagging] Waterway river vs stream
2013/10/19 Jonathan bigfatfro...@gmail.com It seems a river is something that has a source and a mouth (either where it joins the sea, lake or a larger river). So I would say that only streams that have been named River or The River ... should ever be tagged as a river, everything else is a stream. +1, this is also how I do it, if it is called River its a river, regardless of any jumping. If it is something else (like a German Bach, Italian torrente/ruscello) it's a stream. cheers, Martin ___ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
Re: [Tagging] Waterway river vs stream
Ah, but in England we have some Streams that are bigger than Rivers. Stream is sometimes used when a river divides into a number of channels, and some Rivers retain that name even in their upper reaches when they are pretty small (and easily jumpable). So you can't always rely on the name. On Sat, Oct 19, 2013 at 7:35 PM, Martin Koppenhoefer dieterdre...@gmail.com wrote: 2013/10/19 Jonathan bigfatfro...@gmail.com It seems a river is something that has a source and a mouth (either where it joins the sea, lake or a larger river). So I would say that only streams that have been named River or The River ... should ever be tagged as a river, everything else is a stream. +1, this is also how I do it, if it is called River its a river, regardless of any jumping. If it is something else (like a German Bach, Italian torrente/ruscello) it's a stream. cheers, Martin ___ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging ___ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
Re: [Tagging] Waterway river vs stream
On Sat, 2013-10-19 at 22:13 +0200, Christoph Hormann wrote: On Saturday 19 October 2013, Jonathan wrote: It seems a river is something that has a source and a mouth (either where it joins the sea, lake or a larger river). So I would say that only streams that have been named River or The River ... should ever be tagged as a river, everything else is a stream. Be careful here - different languages use different distinctions and even in English use of the terms might differ by country or region. And of course duplicating information that is already in the name tag is not necessary. Just in the UK I can think of Brook, Clough and Beck. And thats just the Midlands and some of the North of England. One option might be to tag every natural watercourse water=stream and strahler=[1...12] and then let the renderer choose how to display it based on the strahler order? No, first of all this kind of topological measure is not possible to determine locally by the mapper since it depends on the whole river system upstream from the point in question (and even more: it requires complete data of it). Second it is not suited for use in map rendering from a cartographic viewpoint. I explained the requirements for an importance rating for rendering of rivers in: http://www.imagico.de/map/water_generalize_en.php The only really important thing for allowing good rendering of the waterways is to have correct orientation and connectivity of all ways - which is a huge problem in the OSM data, in my opinion one of the most severe we have (together with the notoriously broken boundary relations maybe). +1 Phil (trigpoint) ___ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
Re: [Tagging] Waterway river vs stream
On 2013-10-19 22:37, Philip Barnes wrote : On Sat, 2013-10-19 at 22:13 +0200, Christoph Hormann wrote: On Saturday 19 October 2013, Jonathan wrote: It seems a river is something that has a source and a mouth (either where it joins the sea, lake or a larger river). So I would say that only streams that have been named River or The River ... should ever be tagged as a river, everything else is a stream. Be careful here - different languages use different distinctions and even in English use of the terms might differ by country or region. And of course duplicating information that is already in the name tag is not necessary. Just in the UK I can think of Brook, Clough and Beck. And thats just the Midlands and some of the North of England. And in French a rivière that flows to the sea is called a fleuve. I don't think I would call that a stream. The main factor of importance is the flow (m^3 /s), or rather the mean flow. Divided by the section, m^2 , roughly depth × width, that yields the speed (m/s).. And if you divide the flow by the speed and depth, you get the width and you know if you can jump ;-) But, indeed, I prefer spending time on precise traffic tagging so that a GPS does not send a car onto a path or into a river ! Cheers, André. ___ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
