[talk-ch] Confine nazionale impreciso sul Monte Generoso / Ungenaue Landesgrenze auf dem Monte Generoso

Simon Poole simon at poole.ch
Thu Sep 9 17:27:09 CEST 2021


Am 08.09.2021 um 22:05 schrieb Raphael:
> Hello Simon
>
> No problem and thanks for the link!
>
> I've found a data record with the administrative boundaries from 2020.
> [^1] But strangely enough, that boundary [^2] looks totally different
> from swissBOUNDARIES3D. I've connected the boundary stones, whose
> position I have improved using Swissimage, with a way [^3], which is
> pretty congruent with swissBOUNDARIES3D. Do you have an idea why there
> is such a big difference between the boundary by the Regione Lombardia
> and swissBOUNDARIES3D? This can't be because of different geodetic
> systems and i've also never heard that the Swiss-Italian boundary were
> disputed.

As Sascha has pointed out it isn't so simple with "no disputes" but I 
don't think this is the cause for the mismatch. There are at least some 
indications that it might be partially a projection issue, see 
https://cloud.sosm.ch/index.php/s/oJNE5P4dP3db7YG

But in numerous places it seems to simply be different (clearly the 
already mentioned simplification could be part of that)

Simon

> Best regards
>
> Raphael
>
> [^1]:https://www.geoportale.regione.lombardia.it/download-pacchetti?p_p_id=dwnpackageportlet_WAR_gptdownloadportlet&p_p_lifecycle=0&p_p_state=normal&p_p_mode=view&_dwnpackageportlet_WAR_gptdownloadportlet_metadataid=%7BA1D3FFE5-BA78-43BB-8EE5-D892DC55A29F%7D
> [^2]:https://www.openstreetmap.org/way/981025241
> [^3]:https://www.openstreetmap.org/way/981024609
>
>
> On Tue, 7 Sept 2021 at 12:15, Simon Poole<simon at poole.ch>  wrote:
>> Sorry that this has taken so long, our Italian colleagues have pointed
>> tohttps://www.geoportale.regione.lombardia.it/  as a potential source of
>> OGD for the border.
>>
>> Simon
>>
>>
>> Am 05.08.2021 um 22:32 schrieb Raphael:
>>>> There are no boundaries in Lake Constance, there are some ways in OSM to
>>>> close the polygons from a practical pov, but there are no international
>>>> boundaries there that they could correspond to
>>> Thanks for the information. :) (I thought I heard that once, but
>>> wasn't sure anymore.)
>>>
>>>> Politically I don't think it would be a good move to try this again
>>>> right now.
>>> Okay.
>>>
>>>> I can definitely ask OSM Italia for some help with the
>>>> specific issue.
>>> That would be very helpful.
>>>
>>> Cheers
>>>
>>> Raphael
>>>
>>> On Thu, 5 Aug 2021 at 22:09, Simon Poole<simon at poole.ch>  wrote:
>>>> Am 05.08.2021 um 21:31 schrieb Raphael:
>>>>> Hi Simon, hi everyone!
>>>>>
>>>>> Unfortunately, the link on
>>>>> https://wiki.openstreetmap.org/wiki/ISTAT_Italian_Borders  doesn't work
>>>>> anymore. I also can't improve the boundary with the help of the
>>>>> boundary stones, because some stones are missing in OSM. (I couldn't
>>>>> access them because they are in a fenced pasture.) Besides, the
>>>>> boundary from swissBOUNDARIES3D changes its direction more often than
>>>>> there are boundary stones. (Maybe there are some boundary markers on
>>>>> ground level which i haven't noticed.)
>>>>>
>>>>> I've compared the Swiss border in OSM with swissBOUNDARIES3D: While
>>>>> there are only minor differences on the northern boundary from Geneva
>>>>> to the Lower Engadine (except from the Lake Constance, where the
>>>>> boundaries differ up to 1.3 km),
>>>> There are no boundaries in Lake Constance, there are some ways in OSM to
>>>> close the polygons from a practical pov, but there are no international
>>>> boundaries there that they could correspond to (the swisstopo boundaries
>>>> are just as make-believe, simply slightly different dreaming).
>>>>
>>>>> there are larger differences (as i
>>>>> have seen up to 70 m) on the southern boundary (e.g. between Pas de
>>>>> Morgins and Mont Dolent). It doesn't seem that all these differences
>>>>> would come from simplification.
>>>>>
>>>>> It would be very helpful if we could use the new swissBOUNDARIES3D.
>>>>> Who asked Swisstopo at the time if we could use this data?
>>>> I did.
>>>>
>>>> Politically I don't think it would be a good move to try this again
>>>> right now. I can definitely ask OSM Italia for some help with the
>>>> specific issue.
>>>>
>>>> Simon
>>>>
>>>>
>>>>> Best regards
>>>>>
>>>>> Raphael
>>>>>
>>>>> On Tue, 3 Aug 2021 at 12:14, Simon Poole<simon at poole.ch>  wrote:
>>>>>> Am 01.08.2021 um 22:18 schrieb Raphael:
>>>>>>> Hi Simon
>>>>>>>
>>>>>>> Thank you very much for your reply!
>>>>>>>
>>>>>>> The nodes don't seem to have changed since the import (they are all
>>>>>>> version 1). Where can i get the original source to check whether it
>>>>>>> was correct or wrong there? If the original source is correct, i could
>>>>>>> redraw the national border with it.
>>>>>> The problem could be that at the time we (well not me because I was a
>>>>>> neophyte at the time :-)) applied some simplification to the data for
>>>>>> technical reasons, which in general shouldn't cause such problems, but
>>>>>> maybe it is the reason here. Or something else, but I didn't find
>>>>>> anything obvious.
>>>>>>
>>>>>> But in any casehttps://www.openstreetmap.org/node/1372930109  is in the
>>>>>> correct place, buthttps://www.openstreetmap.org/node/1372930116  seems
>>>>>> to be a bit off, it should be further to the east, on the other side.
>>>>>> The simplest way to fix it is to find an Italian open data source for
>>>>>> the coordinates
>>>>>> (https://wiki.openstreetmap.org/wiki/ISTAT_Italian_Borders  maybe), or
>>>>>> survey the boundary stone if there is one there (or it might actually be
>>>>>> visible on imagery).
>>>>>>
>>>>>> Simon
>>>>>>
>>>>>>
>>>>>>> Best regards
>>>>>>>
>>>>>>> Raphael
>>>>>>>
>>>>>>> On Sun, 1 Aug 2021 at 21:59, Simon Poole<simon at poole.ch>  wrote:
>>>>>>>> The thing is that the boundaries were originally imported from
>>>>>>>> swissBoundaries3D with explicit permission from swisstopo see
>>>>>>>> https://wiki.openstreetmap.org/wiki/Switzerland/swissBOUNDARIES3D  . In
>>>>>>>> the mean time the legal situation has changed and have to assume that at
>>>>>>>> least currently the data is off limits.
>>>>>>>>
>>>>>>>> Now naturally the probably more interesting question is why is there
>>>>>>>> such a big difference? Was this in the original data or is it simply an
>>>>>>>> editing error (then likely the issue can be undone).
>>>>>>>>
>>>>>>>> Simon
>>>>>>>>
>>>>>>>> Am 01.08.2021 um 21:22 schrieb Raphael:
>>>>>>>>> Hi everyone
>>>>>>>>>
>>>>>>>>> Can no one tell me if it is still allowed to use swissBOUNDARIES3D?
>>>>>>>>>
>>>>>>>>> Best regards
>>>>>>>>>
>>>>>>>>> Raphael
>>>>>>>>>
>>>>>>>>> On Thu, 22 Jul 2021 at 23:11, Raphael<dafadllyn at gmail.com>  wrote:
>>>>>>>>>> (Unten auf Deutsch)
>>>>>>>>>>
>>>>>>>>>> Ciao a tutti
>>>>>>>>>>
>>>>>>>>>> Ho notato che il confine nazionale sul Monte Generoso è impreciso su
>>>>>>>>>> OSM (errore tra 3 e 10 metri). Per quanto ne so, le cippi di confine
>>>>>>>>>> degli anni 1900 e 1914 sono ancora valide – ma in OSM il confine corre
>>>>>>>>>> accanto alle cippi di confine (esempio [1]). Inoltre, la Cappelletta
>>>>>>>>>> della Madonna della Provvidenza  è in territorio svizzero – ma in OSM
>>>>>>>>>> è in Italia. [2]
>>>>>>>>>>
>>>>>>>>>> Mi è permesso di correggere il confine con l'aiuto di
>>>>>>>>>> swissBOUNDARIES3D [3]? Posso importare lo shapefile direttamente in
>>>>>>>>>> JOSM, o devo ancora convertire il sistema di riferimento delle
>>>>>>>>>> coordinate?
>>>>>>>>>>
>>>>>>>>>> Cordiali saluti
>>>>>>>>>>
>>>>>>>>>> Raphael
>>>>>>>>>>
>>>>>>>>>> [1]:https://www.openstreetmap.org/node/8911035901
>>>>>>>>>> [2]:https://www.openstreetmap.org/way/416328502
>>>>>>>>>> [3]:https://www.swisstopo.admin.ch/de/geodata/landscape/boundaries3d.html
>>>>>>>>>>
>>>>>>>>>> ----
>>>>>>>>>>
>>>>>>>>>> Hallo zusammen
>>>>>>>>>>
>>>>>>>>>> Mir ist aufgefallen, dass die Landesgrenze auf dem Monte Generoso bei
>>>>>>>>>> OSM ungenau verläuft (Fehler zwischen 3 und 10 Meter). Meines Wissens
>>>>>>>>>> sind die Grenzsteine aus den Jahren 1900 und 1914 nach wie vor gültig
>>>>>>>>>> – bei OSM verläuft die Grenze jedoch neben den Grenzsteinen (Beispiel
>>>>>>>>>> [1]). Ausserdem befindet sich die Cappelletta della Madonna della
>>>>>>>>>> Provvidenza auf Schweizer Boden – in OSM befindet sich sich jedoch in
>>>>>>>>>> Italien. [2]
>>>>>>>>>>
>>>>>>>>>> Darf ich die Grenze mithilfe von swissBOUNDARIES3D [3] korrigieren?
>>>>>>>>>> Kann ich das Shapefile direkt in JOSM importieren, oder muss ich noch
>>>>>>>>>> eine Konvertierung des Koordinatenreferenzsystems vornehmen?
>>>>>>>>>>
>>>>>>>>>> Beste Grüsse
>>>>>>>>>>
>>>>>>>>>> Raphael
>>>>>>>>>>
>>>>>>>>>> [1]:https://www.openstreetmap.org/node/8911035901
>>>>>>>>>> [2]:https://www.openstreetmap.org/way/416328502
>>>>>>>>>> [3]:https://www.swisstopo.admin.ch/de/geodata/landscape/boundaries3d.html
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