[Talk-ee] Administrative division

[Jaak Laineste]

I have the scripts what I got from Emilie, not the ones in wiki. These
worked quite fine for my test database upload.

But: I discovered now that my merging of corine with better coastline has a
lot of tiny "topological dust": very small overlappings and
self-intersecting areas. MapInfo found 2400 of them, and each can be
manually fixed, but it took about 15 minutes to fix 30 of them.
www.maakaart.ee/corine_ee_uncleaned.zip has the files in Shape format, so
you can see them in QGIS e.g. - one file for corine polygons, and as 2 for
error checking results. Maybe some errors can be automatically fixed, but
not all of them. For automatic fixing some other workflow/tool is needed to
update Corine with proper coastline. Or just forget about full merging: it
would be easy to have have first step, "masking" for proper sea and this is
it. In my process I tried to have full merging: I extended Corine areas to
coastline, where there would be small holes; and I already did a lot of
manual work to overlook strange bigger areas. Now small technical (possibly
mostly non-visible for renderer) topological errors are left.

/Jaak


> -----Original Message-----
> From: talk-ee-bounces at openstreetmap.org [mailto:talk-ee-
> bounces at openstreetmap.org] On Behalf Of 'Andre Grueneberg'
> Sent: 6. september 2009. a. 12:25
> To: talk-ee at openstreetmap.org
> Subject: Re: [Talk-ee] Administrative division
> 
> Hi Jaak,
> 
> Jaak Laineste wrote:
> >  I think that you do not need relations for merging diffent borders,
> > only to solve 2000-node limit issue. We should just have shared nodes
> of borders.
> 
> At least as far as I can see it's the trend to avoid "left:*" and
> "right:*" and rather have a relation for the entity inside. At least
> that's what http://wiki.openstreetmap.org/wiki/Relation:boundary
> suggests.
> 
> >  My plan:
> > 1. I have merged corine data with of the maaamet shoreline (taken
> from
> > the same admin info). It was manual work 2. I have to add villages,
> > municipalities and maakond borders from maa-amet to the data
> 
> I now have a merged version ...
> http://andre.grueneberg.de/osm/merged_20090601.osm.bz2
> 
> > 3. convert it to using poly2shp . this solves 2000-node limit issues
> 
> Last time I had a look at it, it didn't do what I needed ... so I'm
> hacking around it. :)
> 
> > 4. Run Emilie's duplicate node merging script for the OSM, so all
> > admin levels + corine shoreline nodes should be merged
> 
> Actually I wouldn't merge the administrative borders with the
> coastline.
> At least it doesn't match with international standards. At least up to
> admin_level=6 I'd rather use borders which include multiple islands ...
> otherwise the rendering looks awful.
> 
> BTW: Lately I have added "official" Estonian maritime border to OSM ...
> so we should use it. :)
> 
> > 6. tag new shoreline properly
> 
> What do you mean by that? That's the rather simple part.
> 
> > 7. Remove old and less accurate data from osm (maakond borders,
> > shoreline) as duplicate. Some manual work.
> 
> Oh yes ... some of it is already done ... with 2008 data.
> 
> >  One idea: could you update bulk_upload script, so it has detection
> > feature for duplicate nodes. It should take a way (area) to be
> > uploaded with one step, download existing data for the area, check
> > whether some nodes are already there in the same coordinates, and
> > reuse the nodes. It would make uploading significantly slower, but
> much safer.
> 
> Hmmm ... sounds like a reasonable idea. Only I wonder how to determine
> the bbox to download? How big shall it become? What about densely
> mapped areas (many nodes -> limit)?
> 
> Which version of the script are you currently using?
> 
> Andre
> --
> Mieser Charakter, mieser Verlierer.