[Imports] [NUUG kart] kartverket imports to OpenStreetMap

Tyrfing OSM tyrfingosm at gmail.com
Wed Oct 16 09:59:40 UTC 2013


Hi, thanks for your reply.

2013/10/15 Christoph Hormann <chris_hormann at gmx.de>

> [...]

>From a quick look at your recent edits it seems they are well made and
> the new data is mostly well merged with existing stuff.  But it is
> unavoidable due to the sheer amount of data you add that there are
> mechanical decisions made in the process that would deserve being
> discussed.  This is what makes your edits different from use of Bing
> imagery as source.

I always appreciate comments on my use of tags, that's the best way to
improve. But I would tag the same way if I used a different source or if
the changesets were smaller.


> I see for example most waterways are tagged as
> stream although many are obviously too large for that (waterway=stream
> in combination with width=2 for example already stretches the
> definition of stream and there are streams in your edits significantly
> larger).

I agree that a river is a large stream. To classify a stream as a river one
might consider other aspects than merely the width. E.g: Length, average
discharge (volume rate of water flow), size of the drainage bassin, how
easy it is to cross (which would depend on discharge and width), local
classification/name or relative size compared to other streams in an area
(which then of course might depend on any of the other aspects). Also the
width (and depth, it that was to be considered) tend to vary along the way.

I've noticed that somebody recently added a rule to distinguish
waterway=river from waterway=stream on the wiki page for stream, but I'm
not sure how/where that rule (which is related to how far an able person
can jump) became commonly accepted?

The question on when a stream is considered to be a river has crossed my
mind frequently since I started mapping. I think I was more generous
earlier with using the river tag, but now I tend to reserve river for
waterways which are difficult to cross (due to discharge or a combination
of width and depth) or locally is classified/named as a river (No: "elv" or
"å").


> You also seem to tag all wetlands with wetland=bog but i am
> not sure if this is correct in all cases, especially with wetlands
> around a river.  But i lack the local knowledge to tell if this is
> truely wrong in the individual case.  Again something that would need
> to be discussed if such tag is applied generally to all wetlands and is
> not decided individually.

The wetlands I've edited are mire (No: "myr"). These are either bog or fen,
and the OSM tagging scheme seem to use bog for both. So I still think those
are correct.


> Finally i saw there are various unconnected
> streams like
>
> http://www.openstreetmap.org/browse/way/240629790
> http://www.openstreetmap.org/browse/way/240630383
>
> that are obviously errors and deserve manual checking and fixing.  At
> least they should be tagged with a fixme.
>
Actually I find these quite strange, because these waterways are connected
in the source. Seems like I have deleted the first node. But again, that is
due to manually editing. I'll fix those (and a couple of others along the
same waterway) as soon as I can use the proper source again.


> Note a thorough import discussion could also help with your workflow -
> the lack of orientation in the waterways you fix by hand for example
> can probably mostly be corrected automatically for the whole data set
> based on the elevation data sets kartverket also made available.
> [...]
>
Yes, I assume an import also could create multipolygons, remove double
nodes etc. I'm sceptical to imports because I struggle with the results of
them quite often (like the Corine disaster). Currently I'm happy doing the
edits manually, thus improving the map slowly (compared to an import).

Regards,
T
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