[OSM-talk-ie] Corine Import - update

John Kennedy jkennedyie at gmail.com
Wed Feb 9 14:13:20 GMT 2011


Thanks for the clarifications. Glad I asked re the estates - makes sense and
will save me some work.

Re farm just to point out I based my observation on turning meadow into farm
based on the definitions on OSM. They imply to me that 'meadow' is for land
that is not being farmed. Farm explicitly includes both tillage and pasture.


http://wiki.openstreetmap.org/wiki/Tag:landuse%3Dfarm
http://wiki.openstreetmap.org/wiki/Tag:landuse%3Dmeadow
Some discussion: http://wiki.openstreetmap.org/wiki/Talk:Tag:landuse%3Dfarm

One possibility that avoids changing the OSM wiki definition of meadow/farm
- is it worth proposing qualifications for landuse=farm? e.g.
farm=tillage
farm=pasture

Opening up landuse discussion to bogs too, FYI here is a classification used
in national scientifically rigorous wildlife surveys in Ireland:
http://www.birdwatchireland.ie/Portals/0/images_large/CBS_habitatguide.jpg

[Full credit: the BTO developed this hierarchy. E.g.
http://www.sorby.org.uk/recording/bird-habs.shtml]

I do not propose that we use all of the level 2's, but it might raise
subtleties that would be useful to capture.

Food for thought.
-  John


On 9 February 2011 01:24, Dermot McNally <dermotm at gmail.com> wrote:

> Hi John,
>
> On 9 February 2011 00:47, John Kennedy <jkennedyie at gmail.com> wrote:
>
> > I never used polygons before but I think I have got my head around it on
> the
> > dev box - thanks for setting it up. Will know for sure when I start
> seeing
> > updates after it goes live. I must admit I found some of the polygon
> > highlighting inside JOSM counter-intuitive. e.g. When I highlighted a
> meadow
> > outer, it highlighted the area outside the meadow rather than inside it.
> > This might be related to the large meadow that was split.
>
> Probably this is because you were selecting part of a relation not all
> of whose member elements had been downloaded. As you say, this is
> particularly likely for large polygons. JOSM has an option inside the
> relation edit dialogue to have it download any missing elements - it
> looks a bit like the normal download toolbar button, and you'll
> probably find that the highlighting will fix itself up once you do
> this (but only for the relation in question, so it's often quicker
> just to download a bigger buffer around your editing area).
>
> > The difference between farm and meadow seems arbitrary where I checked -
> > browsing osm wiki I guess most meadow will turn into farm - but if there
> is
> > Irish preference to e.g. tag pasture as meadow pls advise.
>
> I've already mentioned that we may need a consensus on bog, and it
> looks a lot like farmland will need the same thing. If there is a
> sufficient consensus that Corine pastures should not map to OSM
> meadows then we have the option of regenerating the import data set
> with whatever different tagging proves most popular.
>
> But understand that Corine has a few different agricultural land cover
> types, of which the most common ones in Ireland seem to be arable and
> pasture. So far I have been mapping arable to farm and pasture to
> meadow. This is what has been done in at least some of the other
> countries to perform a Corine import. It has the IMO important effect
> of retaining the knowledge that the two uses are different, though I
> note your point that the difference may seem arbitrary - keep in mind
> that this might be due to the fact that many Irish farms are
> sufficiently mixed for the Corine surveyors to have to choose one of
> the two classifications for the entire area. In such cases, the real
> fix is to map the reality at a more detailed level, not to assume that
> the differentiation has no value.
>
> As a non-farmer with _some_ awareness of the countryside, I'll outline
> my gut definitions of the words in question:
>
> Arable: Tillage, the growing of any crop. The brown rendering of the
> OSM farm type seems to suit this
> Pasture: An area under grass for grazing by animals. Seems to merit
> green rendering but may not be a good fit for OSM meadows
> Meadow: An area under grass, ungrazed, to be cut for hay. Seems to
> merit green rendering and to match well to OSM meadows
>
> What is interesting is that Corine has only a pasture category, but
> nothing for meadows. One comment I have read on Corine (unrelated to
> farming) is that it is to capture land cover, not land use. This can
> be the same - a bog being harvested by Bord na Móna is both a land
> cover of bog and an industrial use of that bog. But it's not clear
> that Corine's surveying methods can readily tell the difference
> between areas under grass, nor that they particularly care about the
> difference.
>
> Richard Canwell, who is on this list, may be able to clarify this. OSM
> does have other grass-ish tags, including landuse=grass, so we do have
> options other than to map Corine pastures to meadows just because
> others have done so.
>
> > I have distinct landuse=residential for each estate I mapped. I just used
> > simple continuous way areas with adjacent estates almost touching. I
> might
> > use this import cleanup as opportunity to go the 'refined' route which if
> I
> > understand correctly is:
> >  - create individual ways for each individual border between adjacent
> areas
> >  - create relation of all ways that make an estate border.
> >  - tag the relation with estate name
> > If I have misunderstood pls advise.
>
> Opinions differ about this. Most Irish mappers dislike the gluing of
> areas to linear features like roads, but many do find it useful to
> glue areas together, especially where they have confidence that they
> will not later wish to map something else in between (this is one of
> the better reasons for not gluing residential areas to roads - if you
> later want to map the perimeter fence, where can you put it?)
>
> I map residential areas exactly as you have described above, and I
> think I'll keep doing it this way because it gives me, for instance,
> the option to later map a belt of trees (which is an area, though a
> thin one) between adjacent residential areas, as can arise. Even for
> simpler mapping, the visual separation gained from the hairline
> between adjacent residential areas is IMHO desirable, as it shows the
> extent of a named estate.
>
> > One last thing, it is a signficant change so would recommend a blast to
> all
> > (recent) Irish mappers via internal OSM mail ...just like was done for
> the
> > license change...to bring everyone up to speed before the live import. I
> for
> > one only came across this list recently.
>
> The idea is good, though I'll note that the messages sent regarding
> the licence were sent manually, something that would be cumbersome on
> this occasion. Rorym does have, I think, a script that can do the job
> and has used it before to announce mapping parties, so that option
> remains open to us. My own feeling is that, if we do it, we should
> attempt to exclude mapping tourists and low-volume mappers from the
> notification. The former because the area of imports is rather tainted
> in many OSM circles and a strong opinion not founded on local
> community considerations doesn't necessarily get us anywhere. My one
> concern here is that I'm aware of a very few visitor mappers who have
> mapped landuse, though even those mappers would probably find it
> difficult to recall enough to make their cleanup services useful.
>
> My reason to exclude low-volume mappers is that there is a seriously
> long tail of contributions in Ireland. Low-volume mappers often
> contribute a handful of POIs and/or some road names. Much of our
> message will go over the heads of such mappers, many of whom are using
> simply POI-collecting apps and not full editors.
>
> Regardless, I think we should learn as much as we can from this thread
> before going broader, as it will give us a chance to tune our message
> in a more helpful direction and take some of the techy edge off it.
>
> Thanks for the very useful feedback, and please let's have yours and
> others' suggestions for how to resolve the pasture/meadow issue,
> Dermot
>
>
> --
> --------------------------------------
> Igaühel on siin oma laul
> ja ma oma ei leiagi üles
>
> _______________________________________________
> Talk-ie mailing list
> Talk-ie at openstreetmap.org
> http://lists.openstreetmap.org/listinfo/talk-ie
>


More information about the Talk-ie mailing list