[Tagging] Waterway length

[Sergio Manzi]

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 <mailto: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 <mailto: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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