waterway=wadi problem

classic Classic list List threaded Threaded
45 messages Options
123
Reply | Threaded
Open this post in threaded view
|

waterway=wadi problem

Mateusz Konieczny-2
waterway=wadi is used (18 180 times) and has some support (for example JOSM and
default map style).

During implementing rendering of intermittent=yes I discovered major problem with this tag -
the same waterway=wadi may be used for completely dried up waterway, intermittent stream,
intermittent major river and intermittent ditch.

Therefore - it seems that using waterway=river/canal/stream/ditch/drain + intermittent=yes is
clearly superior to using waterway=wadi.

_______________________________________________
Tagging mailing list
[hidden email]
https://lists.openstreetmap.org/listinfo/tagging
Reply | Threaded
Open this post in threaded view
|

Re: waterway=wadi problem

Wolfgang Zenker
* Mateusz Konieczny <[hidden email]> [150114 15:45]:
> waterway=wadi is used (18 180 times) and has some support (for example JOSM
> and default map style).

> During implementing rendering of intermittent=yes I discovered major
> problem with this tag -
> the same waterway=wadi may be used for completely dried up waterway,
> intermittent stream, intermittent major river and intermittent ditch.

> Therefore - it seems that using waterway=river/canal/stream/ditch/drain +
> intermittent=yes is clearly superior to using waterway=wadi.

In my experience a wadi will go from "completely dried up waterway" or
"small stream" to a raging river within a few seconds after some
rainfall upstream, and back to its former self within a few hours.
Depending on the location, these rainfall events might very well be
a few years apart. When I tag an "intermittent stream" I usually
have something more benign in mind, like a stream that only exists
during the spring snow melt and is dry the rest of the year, but
maybe that is only my interpretation of an intermittent stream.

Wolfgang

_______________________________________________
Tagging mailing list
[hidden email]
https://lists.openstreetmap.org/listinfo/tagging
Reply | Threaded
Open this post in threaded view
|

Re: waterway=wadi problem

Tod Fitch
On Jan 14, 2015, at 8:28 AM, Wolfgang Zenker wrote:

> * Mateusz Konieczny <[hidden email]> [150114 15:45]:
>> waterway=wadi is used (18 180 times) and has some support (for example JOSM
>> and default map style).
>
>> During implementing rendering of intermittent=yes I discovered major
>> problem with this tag -
>> the same waterway=wadi may be used for completely dried up waterway,
>> intermittent stream, intermittent major river and intermittent ditch.
>
>> Therefore - it seems that using waterway=river/canal/stream/ditch/drain +
>> intermittent=yes is clearly superior to using waterway=wadi.
>
> In my experience a wadi will go from "completely dried up waterway" or
> "small stream" to a raging river within a few seconds after some
> rainfall upstream, and back to its former self within a few hours.
> Depending on the location, these rainfall events might very well be
> a few years apart. When I tag an "intermittent stream" I usually
> have something more benign in mind, like a stream that only exists
> during the spring snow melt and is dry the rest of the year, but
> maybe that is only my interpretation of an intermittent stream.
>
> Wolfgang
>
Your description of wadi matches many things locally called a "wash" in the U.S. desert southwest. Yet when I suggested that I tag those as wadi I was shot down. :)

I've taken to tagging them as waterway=river/stream (depending on width) and intermittent=yes. And, yes, in these cases "intermittent" may mean that it only carries water for an hour or two every couple of years.

The United States Geological Survey (USGS) topographic maps will show them as either a line of sand or an intermittent waterway depending, I think, on whim of the cartographer.

A while back I submitted a change to the rendering for OsmAnd to recognize intermittent=yes as without that desert areas look way to wet. For the paper maps that I generate I've also created a Mapnik style that recognizes intermittent=yes and uses the USGS style intermittent rendering. It would be nice if the default rendering at www.openstreetmap.org would also recognize the intermittent tag.




_______________________________________________
Tagging mailing list
[hidden email]
https://lists.openstreetmap.org/listinfo/tagging
Reply | Threaded
Open this post in threaded view
|

Re: waterway=wadi problem

Christoph Hormann
On Wednesday 14 January 2015, Tod Fitch wrote:
> [...]
>
> The United States Geological Survey (USGS) topographic maps will show
> them as either a line of sand or an intermittent waterway depending,
> I think, on whim of the cartographer.

USGS data distinguishes between intermittent, perennial and ephemeral:
 
http://nhd.usgs.gov/userGuide/Robohelpfiles/NHD_User_Guide/Feature_Catalog/Hydrography_Dataset/NHDFlowline/StreamRiver.htm

which well translates into OSM tags:

intermittent: waterway=*, intermittent=yes, seasonal=yes
perennial: waterway=*
ephemeral: waterway=*, intermittent=yes, seasonal=no

although i don't think past imports of NHD data have made this
distinction.

waterway=wadi can mean either intermittent or ephemeral or permanently
dry, see also

https://wiki.openstreetmap.org/wiki/Talk:Tag:waterway%3Dwadi

--
Christoph Hormann
http://www.imagico.de/

_______________________________________________
Tagging mailing list
[hidden email]
https://lists.openstreetmap.org/listinfo/tagging
Reply | Threaded
Open this post in threaded view
|

Re: waterway=wadi problem

Mateusz Konieczny-2
In reply to this post by Tod Fitch
"It would be nice if the default rendering at www.openstreetmap.org would also recognize the intermittent tag."

Implementing that I mentioned in top post is for default style - see
https://github.com/gravitystorm/openstreetmap-carto/pull/1000

2015-01-14 18:00 GMT+01:00 Tod Fitch <[hidden email]>:
On Jan 14, 2015, at 8:28 AM, Wolfgang Zenker wrote:

> * Mateusz Konieczny <[hidden email]> [150114 15:45]:
>> waterway=wadi is used (18 180 times) and has some support (for example JOSM
>> and default map style).
>
>> During implementing rendering of intermittent=yes I discovered major
>> problem with this tag -
>> the same waterway=wadi may be used for completely dried up waterway,
>> intermittent stream, intermittent major river and intermittent ditch.
>
>> Therefore - it seems that using waterway=river/canal/stream/ditch/drain +
>> intermittent=yes is clearly superior to using waterway=wadi.
>
> In my experience a wadi will go from "completely dried up waterway" or
> "small stream" to a raging river within a few seconds after some
> rainfall upstream, and back to its former self within a few hours.
> Depending on the location, these rainfall events might very well be
> a few years apart. When I tag an "intermittent stream" I usually
> have something more benign in mind, like a stream that only exists
> during the spring snow melt and is dry the rest of the year, but
> maybe that is only my interpretation of an intermittent stream.
>
> Wolfgang
>
Your description of wadi matches many things locally called a "wash" in the U.S. desert southwest. Yet when I suggested that I tag those as wadi I was shot down. :)

I've taken to tagging them as waterway=river/stream (depending on width) and intermittent=yes. And, yes, in these cases "intermittent" may mean that it only carries water for an hour or two every couple of years.

The United States Geological Survey (USGS) topographic maps will show them as either a line of sand or an intermittent waterway depending, I think, on whim of the cartographer.

A while back I submitted a change to the rendering for OsmAnd to recognize intermittent=yes as without that desert areas look way to wet. For the paper maps that I generate I've also created a Mapnik style that recognizes intermittent=yes and uses the USGS style intermittent rendering. It would be nice if the default rendering at www.openstreetmap.org would also recognize the intermittent tag.




_______________________________________________
Tagging mailing list
[hidden email]
https://lists.openstreetmap.org/listinfo/tagging


_______________________________________________
Tagging mailing list
[hidden email]
https://lists.openstreetmap.org/listinfo/tagging
Reply | Threaded
Open this post in threaded view
|

Re: waterway=wadi problem

John Willis
In reply to this post by Mateusz Konieczny-2
I strongly disagree. A wadi is usually only an active river through very rare flash flood events, and almost never any other time.  Entire biomes are defined by the presence of (and situated in) a wadi. 

In america, the words Arroyo and wash roughly translate into wadi, and because of the ambiguous nature of arroyo, the term wadi is used for a wash or arroyo when referring to a usually dry stream/riverbed that is dangerous in flash flood conditions. 

my experience with washes stems from the Southern California Desert, where most of the state park would basically be covered in blue, if washes were somehow labeled as rivers - some are 100m across.  Whole road systems exist in the washes (and are reestablished purely by use after a flood), as the rest of the land is almost impassable. 

I have driven a couple thousand miles in a roughly 50x50 mile box over a hundred or so driving trips, and only on 3 occasions was water ever present, and at that time, the roads were completely impassable (a meter or so of water filled up the Carrizo wash 30m wide).

Although several famous arroyos (like the LA River) are now basically man-made drainage ditches, mapping desert areas properly requires the wadi tag, as they are different from intermittent rivers - in the fact that water in the “bed" is *never expected* - even seasonally - and if present it is a dangerous flash flood. There is never an in-between state of what you would call “a river” for longer than a day. - as it disappears almost immediately as soon as the flood is over (except in the most exceptional of weather conditions).  - kind of like an avalanche is only an avalanche while it is moving, or an earthquake is is an event. 

A wadi is a place where flash floods occur. It is not an intermittent river - it isn’t really seasonally wet, and doesn’t provide any real expectation that water will be present (except deep underground) - because they are located in places where rain itself is unexpected for most of the year. 

A wadi has an expectation of always being dry, except for the rare and unpredictable flash flood. t and in that case, you should assume it is a dangerous, and impassable place. 

I think, espcially since it is defined and used so heavily, and has a different connotation than a river - even a intermittent one, it should be kept. 

a wash near Borrego springs, CA (ironwood wash, Tubb canyon). it drains to a sink in the middle of the desert (the white spot in the upper right)



Javbw


On Jan 14, 2015, at 11:45 PM, Mateusz Konieczny <[hidden email]> wrote:

waterway=wadi is used (18 180 times) and has some support (for example JOSM and
default map style).

During implementing rendering of intermittent=yes I discovered major problem with this tag -
the same waterway=wadi may be used for completely dried up waterway, intermittent stream,
intermittent major river and intermittent ditch.

Therefore - it seems that using waterway=river/canal/stream/ditch/drain + intermittent=yes is
clearly superior to using waterway=wadi.
_______________________________________________
Tagging mailing list
[hidden email]
https://lists.openstreetmap.org/listinfo/tagging


_______________________________________________
Tagging mailing list
[hidden email]
https://lists.openstreetmap.org/listinfo/tagging
Reply | Threaded
Open this post in threaded view
|

Re: waterway=wadi problem

John Willis
In reply to this post by Tod Fitch

> On Jan 15, 2015, at 2:00 AM, Tod Fitch <[hidden email]> wrote:
>
>> On Jan 14, 2015, at 8:28 AM, Wolfgang Zenker wrote:
>> In my experience a wadi will go from "completely dried up waterway" or
>> "small stream" to a raging river within a few seconds after some
>> rainfall upstream, and back to its former self within a few hours.
>> Depending on the location, these rainfall events might very well be
>> a few years apart. When I tag an "intermittent stream" I usually
>> have something more benign in mind, like a stream that only exists
>> during the spring snow melt and is dry the rest of the year, but
>> maybe that is only my interpretation of an intermittent stream.
>>
>> Wolfgang

+1. This is exactly how I see the difference - especially since when there is water, it is usually a dangerous, unexpected thing.

> Your description of wadi matches many things locally called a "wash" in the U.S. desert southwest. Yet when I suggested that I tag those as wadi I was shot down.

I added wash as a description to wadi on the osm wiki last year when I was thinking of mapping the San Diego county deserts (as even in Wikipedia it is a round Robbin of links between arroyo and wadi). I'll have to look at the edit history to see if it got pulled off. This was before I understood that adding a description to the wiki was potentially controversial: I thought I was adding something glaringly obvious and helpfully updating the wiki at the same time....

I'm really surprised you were "shot down" from using wadi when it is the most applicable tag for the item, and I'm surprised that there is discussion of axing a well used tag, which defines a known and named geographic feature, for the sake of jamming it under rivers. I always imagine we will be discussion of adding more and more specialized tags, as micro mappers keep labeling smaller an smaller stuff - or. Like the wadi tag - expand our definitions of basic tags to better define what is around us.

I wonder if the people who shot you down have even ever seen a wash, let alone are familiar with them.

I know it's a "no true Scotsman" fallacy, but that's what it feels like.

Javbw

_______________________________________________
Tagging mailing list
[hidden email]
https://lists.openstreetmap.org/listinfo/tagging
Reply | Threaded
Open this post in threaded view
|

Re: waterway=wadi problem

Mateusz Konieczny-2
In reply to this post by John Willis
Can you consider making proposal for waterway=wadi on wiki?
Or maybe other tag, as waterway=wadi is frequently used to mark
intermittent streams?

Currently http://wiki.openstreetmap.org/wiki/Tag:waterway%3Dwadi is
not mentioning anything like that.

Note, I am not disputing usefulness of term wadi. I am disputing usefulness
of waterway=wadi tag due to lack on any agreed definition and description on
OSM wiki.

2015-01-15 3:41 GMT+01:00 johnw <[hidden email]>:
I strongly disagree. A wadi is usually only an active river through very rare flash flood events, and almost never any other time.  Entire biomes are defined by the presence of (and situated in) a wadi. 

In america, the words Arroyo and wash roughly translate into wadi, and because of the ambiguous nature of arroyo, the term wadi is used for a wash or arroyo when referring to a usually dry stream/riverbed that is dangerous in flash flood conditions. 

my experience with washes stems from the Southern California Desert, where most of the state park would basically be covered in blue, if washes were somehow labeled as rivers - some are 100m across.  Whole road systems exist in the washes (and are reestablished purely by use after a flood), as the rest of the land is almost impassable. 

I have driven a couple thousand miles in a roughly 50x50 mile box over a hundred or so driving trips, and only on 3 occasions was water ever present, and at that time, the roads were completely impassable (a meter or so of water filled up the Carrizo wash 30m wide).

Although several famous arroyos (like the LA River) are now basically man-made drainage ditches, mapping desert areas properly requires the wadi tag, as they are different from intermittent rivers - in the fact that water in the “bed" is *never expected* - even seasonally - and if present it is a dangerous flash flood. There is never an in-between state of what you would call “a river” for longer than a day. - as it disappears almost immediately as soon as the flood is over (except in the most exceptional of weather conditions).  - kind of like an avalanche is only an avalanche while it is moving, or an earthquake is is an event. 

A wadi is a place where flash floods occur. It is not an intermittent river - it isn’t really seasonally wet, and doesn’t provide any real expectation that water will be present (except deep underground) - because they are located in places where rain itself is unexpected for most of the year. 

A wadi has an expectation of always being dry, except for the rare and unpredictable flash flood. t and in that case, you should assume it is a dangerous, and impassable place. 

I think, espcially since it is defined and used so heavily, and has a different connotation than a river - even a intermittent one, it should be kept. 

a wash near Borrego springs, CA (ironwood wash, Tubb canyon). it drains to a sink in the middle of the desert (the white spot in the upper right)



Javbw


On Jan 14, 2015, at 11:45 PM, Mateusz Konieczny <[hidden email]> wrote:

waterway=wadi is used (18 180 times) and has some support (for example JOSM and
default map style).

During implementing rendering of intermittent=yes I discovered major problem with this tag -
the same waterway=wadi may be used for completely dried up waterway, intermittent stream,
intermittent major river and intermittent ditch.

Therefore - it seems that using waterway=river/canal/stream/ditch/drain + intermittent=yes is
clearly superior to using waterway=wadi.
_______________________________________________
Tagging mailing list
[hidden email]
https://lists.openstreetmap.org/listinfo/tagging


_______________________________________________
Tagging mailing list
[hidden email]
https://lists.openstreetmap.org/listinfo/tagging



_______________________________________________
Tagging mailing list
[hidden email]
https://lists.openstreetmap.org/listinfo/tagging
Reply | Threaded
Open this post in threaded view
|

Re: waterway=wadi problem

John Willis
I’ll make one up in the next few hours. I want to research wadis in other countries to make sure I’m not assuming my regional experience is misrepresenting the whole. 

Javbw

On Jan 15, 2015, at 3:24 PM, Mateusz Konieczny <[hidden email]> wrote:

Can you consider making proposal for waterway=wadi on wiki?
Or maybe other tag, as waterway=wadi is frequently used to mark
intermittent streams?

Currently http://wiki.openstreetmap.org/wiki/Tag:waterway%3Dwadi is
not mentioning anything like that.

Note, I am not disputing usefulness of term wadi. I am disputing usefulness
of waterway=wadi tag due to lack on any agreed definition and description on
OSM wiki.

2015-01-15 3:41 GMT+01:00 johnw <[hidden email]>:
I strongly disagree. A wadi is usually only an active river through very rare flash flood events, and almost never any other time.  Entire biomes are defined by the presence of (and situated in) a wadi. 

In america, the words Arroyo and wash roughly translate into wadi, and because of the ambiguous nature of arroyo, the term wadi is used for a wash or arroyo when referring to a usually dry stream/riverbed that is dangerous in flash flood conditions. 

my experience with washes stems from the Southern California Desert, where most of the state park would basically be covered in blue, if washes were somehow labeled as rivers - some are 100m across.  Whole road systems exist in the washes (and are reestablished purely by use after a flood), as the rest of the land is almost impassable. 

I have driven a couple thousand miles in a roughly 50x50 mile box over a hundred or so driving trips, and only on 3 occasions was water ever present, and at that time, the roads were completely impassable (a meter or so of water filled up the Carrizo wash 30m wide).

Although several famous arroyos (like the LA River) are now basically man-made drainage ditches, mapping desert areas properly requires the wadi tag, as they are different from intermittent rivers - in the fact that water in the “bed" is *never expected* - even seasonally - and if present it is a dangerous flash flood. There is never an in-between state of what you would call “a river” for longer than a day. - as it disappears almost immediately as soon as the flood is over (except in the most exceptional of weather conditions).  - kind of like an avalanche is only an avalanche while it is moving, or an earthquake is is an event. 

A wadi is a place where flash floods occur. It is not an intermittent river - it isn’t really seasonally wet, and doesn’t provide any real expectation that water will be present (except deep underground) - because they are located in places where rain itself is unexpected for most of the year. 

A wadi has an expectation of always being dry, except for the rare and unpredictable flash flood. t and in that case, you should assume it is a dangerous, and impassable place. 

I think, espcially since it is defined and used so heavily, and has a different connotation than a river - even a intermittent one, it should be kept. 

a wash near Borrego springs, CA (ironwood wash, Tubb canyon). it drains to a sink in the middle of the desert (the white spot in the upper right)



Javbw


On Jan 14, 2015, at 11:45 PM, Mateusz Konieczny <[hidden email]> wrote:

waterway=wadi is used (18 180 times) and has some support (for example JOSM and
default map style).

During implementing rendering of intermittent=yes I discovered major problem with this tag -
the same waterway=wadi may be used for completely dried up waterway, intermittent stream,
intermittent major river and intermittent ditch.

Therefore - it seems that using waterway=river/canal/stream/ditch/drain + intermittent=yes is
clearly superior to using waterway=wadi.
_______________________________________________
Tagging mailing list
[hidden email]
https://lists.openstreetmap.org/listinfo/tagging


_______________________________________________
Tagging mailing list
[hidden email]
https://lists.openstreetmap.org/listinfo/tagging


_______________________________________________
Tagging mailing list
[hidden email]
https://lists.openstreetmap.org/listinfo/tagging


_______________________________________________
Tagging mailing list
[hidden email]
https://lists.openstreetmap.org/listinfo/tagging
Reply | Threaded
Open this post in threaded view
|

Re: waterway=wadi problem

dieterdreist
In reply to this post by John Willis




> Am 15.01.2015 um 05:27 schrieb John Willis <[hidden email]>:
>
> I'm really surprised you were "shot down" from using wadi when it is the most applicable tag for the item,


sometimes the most applicable tag is not sufficiently well describing/ distinguishing a feature and it is better to introduce a new tag that fits 100%

To me, the Term "wadi" is quite specific for certain waterways that occur in a certain region of the world. We can decide whether we'd want to use it anyway everywhere for "similar" (or partly similar) features or if we introduce other, dedicated  tags on the same level of specificity for these features. Why not having a tag waterway=wash, or are those really the same than a "wadi"?

cheers,
Martin
_______________________________________________
Tagging mailing list
[hidden email]
https://lists.openstreetmap.org/listinfo/tagging
Reply | Threaded
Open this post in threaded view
|

Re: waterway=wadi problem

Christoph Hormann
In reply to this post by John Willis
On Thursday 15 January 2015, johnw wrote:
>
> A wadi is a place where flash floods occur. It is not an intermittent
> river - it isn’t really seasonally wet, and doesn’t provide any real
> expectation that water will be present (except deep underground) -
> because they are located in places where rain itself is unexpected
> for most of the year.

Well - that would be a useful concept of a wadi but it has two problems:

* current use of the tag is very different from that, you can see that
quite well when you look at the taginfo map:

https://taginfo.openstreetmap.org/tags/waterway=wadi#map

the uses in Europe for example are probably almost always seasonal.

* sporadic waterflow is very difficult to determine for the mapper.  
This is especially true for northern Africa where climate got a lot
drier in the last few thousand years and as a result there are many
permanently dry valleys that still look like being formed by waterflow
but that have not seen significant waterflow in the last hundred years.

My suggestion would probably be to stop rendering waterway=wadi in a way
implying waterflow, encourage mappers to use intermittent/seasonal
where this is known and reserve waterway=wadi - despite the then
misleading key - for valleys where waterflow is unknown.

--
Christoph Hormann
http://www.imagico.de/

_______________________________________________
Tagging mailing list
[hidden email]
https://lists.openstreetmap.org/listinfo/tagging
Reply | Threaded
Open this post in threaded view
|

Re: waterway=wadi problem

John F. Eldredge
I would recommend expanding the definition of "intermittent streams" to
include not only streams that have a regular, seasonal water flow but also
streams in desert areas that exist only when a rare storm comes along. The
topography is the same, the tendency of water to run downhill is the same,
only the frequency of rainfall is different.

--
John F. Eldredge -- [hidden email]
"Darkness cannot drive out darkness; only light can do that. Hate cannot
drive out hate; only love can do that." -- Martin Luther King, Jr.



On January 15, 2015 3:13:38 AM Christoph Hormann <[hidden email]> wrote:

> On Thursday 15 January 2015, johnw wrote:
> >
> > A wadi is a place where flash floods occur. It is not an intermittent
> > river - it isn’t really seasonally wet, and doesn’t provide any real
> > expectation that water will be present (except deep underground) -
> > because they are located in places where rain itself is unexpected
> > for most of the year.
>
> Well - that would be a useful concept of a wadi but it has two problems:
>
> * current use of the tag is very different from that, you can see that
> quite well when you look at the taginfo map:
>
> https://taginfo.openstreetmap.org/tags/waterway=wadi#map
>
> the uses in Europe for example are probably almost always seasonal.
>
> * sporadic waterflow is very difficult to determine for the mapper.
> This is especially true for northern Africa where climate got a lot
> drier in the last few thousand years and as a result there are many
> permanently dry valleys that still look like being formed by waterflow
> but that have not seen significant waterflow in the last hundred years.
>
> My suggestion would probably be to stop rendering waterway=wadi in a way
> implying waterflow, encourage mappers to use intermittent/seasonal
> where this is known and reserve waterway=wadi - despite the then
> misleading key - for valleys where waterflow is unknown.
>
> --
> Christoph Hormann
> http://www.imagico.de/
>
> _______________________________________________
> Tagging mailing list
> [hidden email]
> https://lists.openstreetmap.org/listinfo/tagging



_______________________________________________
Tagging mailing list
[hidden email]
https://lists.openstreetmap.org/listinfo/tagging
Reply | Threaded
Open this post in threaded view
|

Re: waterway=wadi problem

John Willis
In reply to this post by dieterdreist
as far as I am aware, a wash, an arroyo, and a wadi are functionally the same. It is mostly a separation of language - where the words wash, arroyo, and wadi are basically the same functional thing, however Wadi and arroyo, in some regions, also have a wider definition that includes other valley definitions. 

as it might be confusing to have three tags for the same thing (A lot of washes in California have Spanish names using the word Arroyo (“Arroyo Seco Del Diablo” ) and we have a de facto established tag with wadi, it seems like making three tags for the same functional item is overkill - as long as we preface that whatever it is being tagged functionally be a “wadi", not one in name only.

That seems like a small caveat to avoid confusion between 3 tags. 

If avoiding that confusion at all costs means 3 tags, then lets make three tags - waterway=arroyo, waterway=wash, waterway=wadi and the different nuances between what really defines the tag can be spelled out on each page, and regional taggers can find a tag they are familiar with.


I spelled out my definition of a wadi on the waterway=wadi talk page. 

I look forward to further input, especially anyone who lives in a region with things called "wadis" - as my experience is with “washes" in California.

Javbw. 


On Jan 15, 2015, at 6:09 PM, Martin Koppenhoefer <[hidden email]> wrote:





Am 15.01.2015 um 05:27 schrieb John Willis <[hidden email]>:

I'm really surprised you were "shot down" from using wadi when it is the most applicable tag for the item,


sometimes the most applicable tag is not sufficiently well describing/ distinguishing a feature and it is better to introduce a new tag that fits 100%

To me, the Term "wadi" is quite specific for certain waterways that occur in a certain region of the world. We can decide whether we'd want to use it anyway everywhere for "similar" (or partly similar) features or if we introduce other, dedicated  tags on the same level of specificity for these features. Why not having a tag waterway=wash, or are those really the same than a "wadi"?

cheers,
Martin
_______________________________________________
Tagging mailing list
[hidden email]
https://lists.openstreetmap.org/listinfo/tagging


_______________________________________________
Tagging mailing list
[hidden email]
https://lists.openstreetmap.org/listinfo/tagging
Reply | Threaded
Open this post in threaded view
|

Re: waterway=wadi problem

Eugene Alvin Villar
In reply to this post by John F. Eldredge
Given the current discussion, I wonder if roads that are usually flooded during heavy rainfall should be also be tagged as waterway=river/stream and intermittent=yes. ;-)

On Fri, Jan 16, 2015 at 7:27 AM, John F. Eldredge <[hidden email]> wrote:
I would recommend expanding the definition of "intermittent streams" to include not only streams that have a regular, seasonal water flow but also streams in desert areas that exist only when a rare storm comes along. The topography is the same, the tendency of water to run downhill is the same, only the frequency of rainfall is different.

--
John F. Eldredge -- [hidden email]
"Darkness cannot drive out darkness; only light can do that. Hate cannot drive out hate; only love can do that." -- Martin Luther King, Jr.




On January 15, 2015 3:13:38 AM Christoph Hormann <[hidden email]> wrote:

On Thursday 15 January 2015, johnw wrote:
>
> A wadi is a place where flash floods occur. It is not an intermittent
> river - it isn’t really seasonally wet, and doesn’t provide any real
> expectation that water will be present (except deep underground) -
> because they are located in places where rain itself is unexpected
> for most of the year.

Well - that would be a useful concept of a wadi but it has two problems:

* current use of the tag is very different from that, you can see that
quite well when you look at the taginfo map:

https://taginfo.openstreetmap.org/tags/waterway=wadi#map

the uses in Europe for example are probably almost always seasonal.

* sporadic waterflow is very difficult to determine for the mapper.
This is especially true for northern Africa where climate got a lot
drier in the last few thousand years and as a result there are many
permanently dry valleys that still look like being formed by waterflow
but that have not seen significant waterflow in the last hundred years.

My suggestion would probably be to stop rendering waterway=wadi in a way
implying waterflow, encourage mappers to use intermittent/seasonal
where this is known and reserve waterway=wadi - despite the then
misleading key - for valleys where waterflow is unknown.

--
Christoph Hormann
http://www.imagico.de/

_______________________________________________
Tagging mailing list
[hidden email]
https://lists.openstreetmap.org/listinfo/tagging



_______________________________________________
Tagging mailing list
[hidden email]
https://lists.openstreetmap.org/listinfo/tagging


_______________________________________________
Tagging mailing list
[hidden email]
https://lists.openstreetmap.org/listinfo/tagging
Reply | Threaded
Open this post in threaded view
|

Re: waterway=wadi problem

John Willis
In reply to this post by Christoph Hormann



> On Jan 15, 2015, at 6:13 PM, Christoph Hormann <[hidden email]> wrote:
>
> On Thursday 15 January 2015, johnw wrote:
>>
>> A wadi is a place where flash floods occur. It is not an intermittent
>> river - it isn’t really seasonally wet, and doesn’t provide any real
>> expectation that water will be present (except deep underground) -
>> because they are located in places where rain itself is unexpected
>> for most of the year.
>
> Well - that would be a useful concept of a wadi but it has two problems:
>
> * current use of the tag is very different from that, you can see that
> quite well when you look at the taginfo map:
>
> https://taginfo.openstreetmap.org/tags/waterway=wadi#map
>
> the uses in Europe for example are probably almost always seasonal.
> * sporadic waterflow is very difficult to determine for the mapper.  
> This is especially true for northern Africa where climate got a lot
> drier in the last few thousand years and as a result there are many
> permanently dry valleys that still look like being formed by waterflow
> but that have not seen significant waterflow in the last hundred years.
>
> My suggestion would probably be to stop rendering waterway=wadi in a way
> implying waterflow, encourage mappers to use intermittent/seasonal
> where this is known and reserve waterway=wadi - despite the then
> misleading key - for valleys where waterflow is unknown.
>

if it is the case that wadis are

- not following my definition of a wadi

- not currently tagged on wadis


Then spitting off waterway=wash is the best idea, because

- it is a defined geographic feature

- is labeled and well known in the regions they exist, and are easy to tell apart to regional mappers.

- and most importantly (to me) has a much different connotation than “intermittant stream”

- more accurately describes the world as it exists.

However all those tags in Africa and the Americas are probably correctly tagged.

I bet cleanup of this tag will require some re-tagging, or a much broader definition of wadi - which would turn it into an intermittent  or seasonal stream/river, so what’s the point of having the tag then…

thanks for the useful data/map.


> --
> Christoph Hormann
> http://www.imagico.de/
>
> _______________________________________________
> Tagging mailing list
> [hidden email]
> https://lists.openstreetmap.org/listinfo/tagging


_______________________________________________
Tagging mailing list
[hidden email]
https://lists.openstreetmap.org/listinfo/tagging
Reply | Threaded
Open this post in threaded view
|

Re: waterway=wadi problem

John Willis
In reply to this post by Eugene Alvin Villar
That’s all of San Diego - the storm drain system is so anemic - I’ve hydroplaned my car down the freeway (“Surfing interstate 5”), and forded a few “intermittent” rivers before I moved to Japan. here in Japan, torrential rain is really a non-issue most of the time - whereas a few cm of rain in Southern California means death on the roads and flooding underpasses. maybe it’s all the bald tires, oily roads, and people going 30-40km/h over what they should be driving.  One wonders.  ^_^

Javbw

On Jan 16, 2015, at 9:27 AM, Eugene Alvin Villar <[hidden email]> wrote:

Given the current discussion, I wonder if roads that are usually flooded during heavy rainfall should be also be tagged as waterway=river/stream and intermittent=yes. ;-)

On Fri, Jan 16, 2015 at 7:27 AM, John F. Eldredge <[hidden email]> wrote:
I would recommend expanding the definition of "intermittent streams" to include not only streams that have a regular, seasonal water flow but also streams in desert areas that exist only when a rare storm comes along. The topography is the same, the tendency of water to run downhill is the same, only the frequency of rainfall is different.

--
John F. Eldredge -- [hidden email]
"Darkness cannot drive out darkness; only light can do that. Hate cannot drive out hate; only love can do that." -- Martin Luther King, Jr.




On January 15, 2015 3:13:38 AM Christoph Hormann <[hidden email]> wrote:

On Thursday 15 January 2015, johnw wrote:
>
> A wadi is a place where flash floods occur. It is not an intermittent
> river - it isn’t really seasonally wet, and doesn’t provide any real
> expectation that water will be present (except deep underground) -
> because they are located in places where rain itself is unexpected
> for most of the year.

Well - that would be a useful concept of a wadi but it has two problems:

* current use of the tag is very different from that, you can see that
quite well when you look at the taginfo map:

https://taginfo.openstreetmap.org/tags/waterway=wadi#map

the uses in Europe for example are probably almost always seasonal.

* sporadic waterflow is very difficult to determine for the mapper.
This is especially true for northern Africa where climate got a lot
drier in the last few thousand years and as a result there are many
permanently dry valleys that still look like being formed by waterflow
but that have not seen significant waterflow in the last hundred years.

My suggestion would probably be to stop rendering waterway=wadi in a way
implying waterflow, encourage mappers to use intermittent/seasonal
where this is known and reserve waterway=wadi - despite the then
misleading key - for valleys where waterflow is unknown.

--
Christoph Hormann
http://www.imagico.de/

_______________________________________________
Tagging mailing list
[hidden email]
https://lists.openstreetmap.org/listinfo/tagging



_______________________________________________
Tagging mailing list
[hidden email]
https://lists.openstreetmap.org/listinfo/tagging

_______________________________________________
Tagging mailing list
[hidden email]
https://lists.openstreetmap.org/listinfo/tagging


_______________________________________________
Tagging mailing list
[hidden email]
https://lists.openstreetmap.org/listinfo/tagging
Reply | Threaded
Open this post in threaded view
|

Re: waterway=wadi problem

voschix
Looking around in Wikipedia:
Wash = Arroyo  =  Barranca = Wadi = Rambla = normally dry river bed, often subject to flash floods in case of upstream rain.

If we have the the established term wadi for this, why create additional nearly synonymous tags?





_______________________________________________
Tagging mailing list
[hidden email]
https://lists.openstreetmap.org/listinfo/tagging
Reply | Threaded
Open this post in threaded view
|

Re: waterway=wadi problem

Richard Z.
In reply to this post by John Willis
On Thu, Jan 15, 2015 at 11:41:26AM +0900, johnw wrote:
> I strongly disagree. A wadi is usually only an active river through very rare flash flood events, and almost never any other time.  Entire biomes are defined by the presence of (and situated in) a wadi.
>

how about reading wikipedia?
<<
Wadi (Arabic: وادي‎ wādī) is the Arabic term traditionally referring to a valley. In some cases, it may refer to a dry (ephemeral) riverbed that contains water only during times of heavy rain or simply an intermittent stream.
>>

I consider a wadi a geologic feature. In addition to the above wadis are expected
to carry underground water.

Richard


_______________________________________________
Tagging mailing list
[hidden email]
https://lists.openstreetmap.org/listinfo/tagging
Reply | Threaded
Open this post in threaded view
|

Re: waterway=wadi problem

voschix
I now notice that I read the German Wikipedia entry for Wadi, which is plainly different form the English one. My fault.
The English Wikipedia defines Wadi mainly as a valley, wheras the German on as a normally dry water course.


On 16 January 2015 at 13:02, Richard Z. <[hidden email]> wrote:
On Thu, Jan 15, 2015 at 11:41:26AM +0900, johnw wrote:
> I strongly disagree. A wadi is usually only an active river through very rare flash flood events, and almost never any other time.  Entire biomes are defined by the presence of (and situated in) a wadi.
>

how about reading wikipedia?
<<
Wadi (Arabic: وادي‎ wādī) is the Arabic term traditionally referring to a valley. In some cases, it may refer to a dry (ephemeral) riverbed that contains water only during times of heavy rain or simply an intermittent stream.
>>

I consider a wadi a geologic feature. In addition to the above wadis are expected
to carry underground water.

Richard


_______________________________________________
Tagging mailing list
[hidden email]
https://lists.openstreetmap.org/listinfo/tagging


_______________________________________________
Tagging mailing list
[hidden email]
https://lists.openstreetmap.org/listinfo/tagging
Reply | Threaded
Open this post in threaded view
|

Re: waterway=wadi problem

Tod Fitch
Since we are supposed to use British English, I decided to look up wadi in my old paper edition of the Oxford English Dictionary (can we trust that more than Wikipedia?):

"Wadi or Wady [Arabic: وادي‎ wādī] In certain Arabic speaking countries, a ravine or valley which in the rainy season becomes a watercourse; the stream or torrent running through such a ravine."

Apparently first used in English literature in 1839 by the way.

So it seems it could either be the valley or the actual intermittent watercourse. In that respect the term "wash" in the U.S. southwest is more specific as it is only applied to the intermittent watercourse. My impression from Southern California is that arroyo can be the valley/ravine as well as the actual watercourse, so that might match the OED definition of wadi more than "wash" does.

Tod

On Jan 16, 2015, at 5:36 AM, Volker Schmidt wrote:

I now notice that I read the German Wikipedia entry for Wadi, which is plainly different form the English one. My fault. 
The English Wikipedia defines Wadi mainly as a valley, wheras the German on as a normally dry water course. 


On 16 January 2015 at 13:02, Richard Z. <[hidden email]> wrote:
On Thu, Jan 15, 2015 at 11:41:26AM +0900, johnw wrote:
> I strongly disagree. A wadi is usually only an active river through very rare flash flood events, and almost never any other time.  Entire biomes are defined by the presence of (and situated in) a wadi.
>

how about reading wikipedia?
<<
Wadi (Arabic: وادي‎ wādī) is the Arabic term traditionally referring to a valley. In some cases, it may refer to a dry (ephemeral) riverbed that contains water only during times of heavy rain or simply an intermittent stream.
>>

I consider a wadi a geologic feature. In addition to the above wadis are expected
to carry underground water.

Richard


_______________________________________________
Tagging mailing list
[hidden email]
https://lists.openstreetmap.org/listinfo/tagging

_______________________________________________
Tagging mailing list
[hidden email]
https://lists.openstreetmap.org/listinfo/tagging


_______________________________________________
Tagging mailing list
[hidden email]
https://lists.openstreetmap.org/listinfo/tagging
123