On Thu, Sep 13, 2018 at 10:02 AM Martin Koppenhoefer
wrote:
> you’ll have to put the ridges to map the watersheds anyway, the catchment
> basin is implicit with the waterways, coastlines and ridges.
>
> If there are names or other properties for the watersheds and catchment
> basins in play,
sent from a phone
> On 13. Sep 2018, at 10:02, Joseph Eisenberg
> wrote:
>
> "do we really have to map this explicitly with relations? Can’t you already
> see them from the waterway and ridge data?"
>
> 1) Ridges are missing in many parts of the world, partially because they are
> not
On Thursday 13 September 2018, Joseph Eisenberg wrote:
> Christoph,
> So you believe the ridges are verifiable (and the network of
> waterways, I assume), but potentially parts of the watershed would
> not be verifiable because eg. terrain is too flat?
There are many reasons why a the watershed
"In fact this does occur, a river can disappear into the sand!
And some lakes have no outflow."
Right, these are called an "endorheic basin"; an area where the water flow
does not reach the ocean: https://en.wikipedia.org/wiki/Endorheic_basin
In one of my examples above, the river disappears into
I believe some waterways in Australia will flow away from wherever the
rain happens to fall ...
That is a produce not just of the flatness of the terrain but also to
the quantity of rain - there can be 5 years of rainfall delivered in a
single day.
Someone has put in the Australian Great
(Sorry, Lake Habema is https://www.openstreetmap.org/relation/8688509)
On Thu, Sep 13, 2018 at 7:12 PM Joseph Eisenberg
wrote:
> Christoph,
> So you believe the ridges are verifiable (and the network of waterways, I
> assume), but potentially parts of the watershed would not be verifiable
>
Christoph,
So you believe the ridges are verifiable (and the network of waterways, I
assume), but potentially parts of the watershed would not be verifiable
because eg. terrain is too flat? I was thinking that in fairly flat areas
it is still possbile to see which way water flows in drainage
On Thursday 13 September 2018, Joseph Eisenberg wrote:
> Relations of type=watershed are currently used over 2000 times and
> there is a descriptive Wiki page but no proposal. (
> https://wiki.openstreetmap.org/wiki/Relation:watershed)
>
> It would be useful to have a relation that showed drainage
"do we really have to map this explicitly with relations? Can’t you already
see them from the waterway and ridge data?"
1) Ridges are missing in many parts of the world, partially because they
are not rendered, but also because it might not be clear how they can be
useful. The presence of
do we really have to map this explicitly with relations? Can’t you already see
them from the waterway and ridge data? IIRR, people have been rendering maps
for these in the past by just analyzing existing waterway data, no need for
explicit watersheds.
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