[Tagging] Waterway length

[Eugene Podshivalov]

>
> it is wrongly named (distance instead of length)

Has already been corrected (at least in the english wiki)

> it can assume multiple different values according to different sources

"length:source" can resolve this if needed.

> it is unverifiable "on the ground"

it is IMNSHO useless (*just point to a Wikipedia article to get this
> information*)

Let me ask you a question please: how do you verify "name:es" of a river
which flows in France?
Should we delete all "name:<lang>" tags and direct users to wikipedia
instead?

For that I guess  a better solution would be to use the fixme=* tag:
> "fixme: check that this river length is between 5499 and 7088 Km", for the
> Nile.

This would mean keeping fixme=* tag in every waterway relation forever
which contradicts its purpose.

Cheers,
Eugene

вс, 17 февр. 2019 г. в 16:36, Sergio Manzi <smz at smz.it>:

> I think I know understand what usage you want to do of that "waterway
> length" datum (*or at  least that's what I'm reading in your last message*):
> use it as a "control" for checking if the waterway's segments add up to the
> "official" (*whatever that can mean...*) waterway length.  Or at least in
> part: that datum will be close to useless to check waterways with the
> complexity of the "*river of a hundred waterways*" and many similar ones.
>
> For that I guess  a better solution would be to use the fixme=* tag:
> "fixme: check that this river length is between 5499 and 7088 Km", for the
> Nile.
>
> TBH I see A LOT of issues with this tag:
>
>    - it is wrongly named (*distance instead of length*)
>    - it is unverifiable "on the ground"
>    - it can assume multiple different values according to different
>    sources
>    - it is IMNSHO useless (*just point to a Wikipedia article to get this
>    information*)
>
> Personally I'm leaning to propse to deprecate the usage of this key and
> subject that to a vote. What is the process for that?
>
> Sergio
>
>
> On 2019-02-17 14:07, Eugene Podshivalov wrote:
>
> вс, 17 февр. 2019 г. в 15:18, Sergio Manzi <smz at smz.it>:
>>
>>   That's as old as data processing: "*garbage in, garbage out*". Let's
>> fix the data.
>
> Fixing data is a good thing but from utilization in production point of
> view the choice between unstable and stable data is not questioned.
> Competeness of data is even more important than its stability, and that
> unfortunately cannot be achieved that quickly. One can create a waterway
> relation with a length defined and then there may be a long run until all
> waterway segments are drawn properly to finally be able to compare it to an
> official length.
>
> You'll probably can find many different estimations about its length.
>> Which one are you going to choose?
>
>  I would take one from any encyclopedia (subject to its license) and that
> figure will at least serve other mappers as a guidence when searching for
> incomplete or broken rivers.
>
> Cheers,
> Eugene
>
>
> вс, 17 февр. 2019 г. в 15:18, Sergio Manzi <smz at smz.it>:
>
>> On 2019-02-17 12:55, Eugene Podshivalov wrote:
>>
>>
>> It will work but only if the entire river from its spring to mouth is
>> drawn precisely enough, all relation roles are labeled properly and nobody
>> breaks the labeling by intent or mistake some day.
>>
>> That's as old as data processing: "*garbage in, garbage out*". Let's fix
>> the data.
>>
>> And yes, the river you pointed at is particularly complex and probably
>> geographers are pulling each other's hairs about computing its length.
>> You'll probably can find many different estimations about its length. Which
>> one are you going to choose?
>>
>> Sergio
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