[Imports] Import of forests, farmland and other types of land cover for Sweden generated from Naturvårdsverkets Nationella Marktäckedata 2018

Peter Barth osm-peda at won2.de
Tue Apr 23 20:53:49 UTC 2019


Hi,

I just read this thread. I had the impression that valid criticism and
feedback by Christoph had been mostly ignored (well, as usual I'd say :/).
I wouldn't have expected an import to start after this thread, but it
was started a week after (as announced). So I had a quick look at the
data and import and I'm not really surprised but I feel the need to
comment on the low/bad quality I perceived from this quick peek.

I didn't read the plan btw, but wanted to read the ML if there really
was community acceptance as any note about this was left out in this 
thread. A huge thread, all swedish, so no idea if swedish community is 
ok or not. Did they accept or decline or abstain?!

I continued with the status[1] to read some strange comment about DP 
smoothing that resulted in some way shifting. Suspicious imho, so I 
wanted to check these changesets. The first 16 of those changesets 
uploaded nodes, 10k each of them (i.e. total of 160000 nodes). No ways 
or relations. Ok, so a huge change, split into changesets leaving 
traceability to the mapper instead of the importer. As always, I want
to add. Changeset Nr. 17[2] actually adds something. Of course again 
a quite large one but at least achavi[3] could load it. So let's have a 
quick look.

Almost only new ways and it seems everything is tagged with
landuse=forest, no matter if it's natural scrub or wetland or whatever
else. Seems wrong to me and taginfo[4].

I opened a small test area in an editor, a small island[5]. It has an
offset to all imageries out there. Ok, imagery can be wrong for sure.
But outlines also don't match. Strange, but ok. A bit more to the east
I noticed the lakeshore: It intersects the forests multiple times. 
Strange. A bit to the south, the island Lövholmen intersects the forest
yet again. And so on and so on.

>From this quite small random sample I'd argue that this is a very low
quality import. I'm not really astonished about that, but I'm
questioning if it isn't time to increase our quality standards wrt
imports and introduce import permissions as opposed to just ignore
criticism and wait a week or two to import. No offense to Grigory, but 
we see this again and again that someone with some programming skills 
finds a data set to import, hacks and uses some tools, imports that and 
expects the wider community to eventually fix all bugs. I think that 
the bar for imported data should be way above the quality of an average 
mapper's data.

Regards,
Peda

[1] https://wiki.openstreetmap.org/wiki/Import/Catalogue/NMD_2018_Import_Plan/Status_per_subarea
[2] https://www.openstreetmap.org/changeset/69451277#map=11/59.0810/15.8871
[3] https://overpass-api.de/achavi/?changeset=69451277#map=11
[4] https://taginfo.openstreetmap.org/tags/natural=scrub#combinations
[5] https://www.openstreetmap.org/edit?editor=id#map=17/59.03507/16.07117




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