[Talk-ca] Maritime Boundary
Hello! I have a question regarding the maritime boundary of Canada, specifically Newfoundland and Labrador. National maritime boundaries generally use the 12 nautical mile limit, unless otherwise specified. I see the boundary for the province (http://www.openstreetmap.org/#map=7/48.283/-53.196) which is auto-generated by a bot. That seems fine, but there is another maritime boundary for the Province. However, this one does not appear to be correct. Take a look at this example - http://www.openstreetmap.org/#map=14/47.7920/-52.7985. As you can see, the dashed line represents the boundary - in ID, it is noted as the maritime boundary. But that does not make sense - the line crosses the landmass, for one thing. It is also very poorly shaped. Is this supposed to be the actual maritime boundary? I don't think it is - the parts of the line appears to be for the Provincial boundary. If it is the Provincial boundary, shouldn't it follow the coastal boundary? If I am mistaken, let me know. Adam ___ Talk-ca mailing list Talk-ca@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk-ca
Re: [Talk-ca] Maritime Boundary
On Sun, Jan 12, 2014 at 9:05 PM, Adam Martin s.adam.mar...@gmail.com wrote: Hello! Is this supposed to be the actual maritime boundary? I don't think it is - the parts of the line appears to be for the Provincial boundary. If it is the Provincial boundary, shouldn't it follow the coastal boundary? If I am mistaken, let me know. I don't think that you are mistaken, but I don't think you have all of the facts either. The 12NM line does look to be one that was created automatically. It certainly wasn't surveyed by a local mapper. :-) Same for the inland maritime boundary. I looked at that one in more detail. Here's what I see going on. The boundary way is this one http://www.openstreetmap.org/way/30114485 It is also part of two relations. One relation is a civil boundary, the other is an administrative (provincial) Boundary ways can not be understood fully, or edited wisely, without understanding relations. I wouldn't edit any complex form, such as a boundary relation, with an editor other than JOSM. And not with any editor, on a mobile device. Today, the way appears badly drawn, and incomplete in tagging. I'll take a few guesses at why. The history of that way shows 28 revisions. The first one was the creation of the way, as an import from geobase in 2009. It was tagged as an administrative boundary (not a maritime boundary). Likely, this was the best data available to us at the time. With the currently available imagery, we can see that the imported boundary does not align with imagery, nor does it reflect some of the details in the current imagery. Revisions 2 through 25 have been redacted, due to edits by users who did not agree to the license change. The boundary may have had some improvements and corrections through those edits. Improved or otherwise, those edits are gone. Revision 26 shows that the redaction bot cleaned out the data that we were no longer entitled to keep. That left the way without tags. R27 in 2012 appears not to have directly affected the way. It may have edited an intersecting way? It was a large changeset. R28 in 2013 added the maritime tag you report. The maritime tag alone, is an unusual form. I don't think that it would be considered complete, unless combined with the tags of the parent relations. When compared with the 'bot-drawn 12nm maritime boundary, this way appears to be incorrect. It just doesn't seem to be far enough offshore to be a maritime boundary. When compared to http://www.openstreetmap.org/way/115038287 (from 2011, and a canvec import) the '485 way appears low resolution and poorly aligned. So there are are multiple imported boundaries here. Each were the probably best available at the time. Neither are perfect, and now the appear to somewhat duplicate each other, given the parent relations of '485. Hope that helps a bit. ___ Talk-ca mailing list Talk-ca@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk-ca
Re: [Talk-ca] Maritime Boundary
It seems to me that the provincial boundary should be displaced from the coast of the Island of Newfoundland by 3 NM. Is there a tool one can use to do that? - David E. Nelson On Sunday, January 12, 2014 8:00:21 PM, Richard Weait rich...@weait.com wrote: On Sun, Jan 12, 2014 at 9:05 PM, Adam Martin s.adam.mar...@gmail.com wrote: Hello! Is this supposed to be the actual maritime boundary? I don't think it is - the parts of the line appears to be for the Provincial boundary. If it is the Provincial boundary, shouldn't it follow the coastal boundary? If I am mistaken, let me know. I don't think that you are mistaken, but I don't think you have all of the facts either. The 12NM line does look to be one that was created automatically. It certainly wasn't surveyed by a local mapper. :-) Same for the inland maritime boundary. I looked at that one in more detail. Here's what I see going on. The boundary way is this one http://www.openstreetmap.org/way/30114485 It is also part of two relations. One relation is a civil boundary, the other is an administrative (provincial) Boundary ways can not be understood fully, or edited wisely, without understanding relations. I wouldn't edit any complex form, such as a boundary relation, with an editor other than JOSM. And not with any editor, on a mobile device. Today, the way appears badly drawn, and incomplete in tagging. I'll take a few guesses at why. The history of that way shows 28 revisions. The first one was the creation of the way, as an import from geobase in 2009. It was tagged as an administrative boundary (not a maritime boundary). Likely, this was the best data available to us at the time. With the currently available imagery, we can see that the imported boundary does not align with imagery, nor does it reflect some of the details in the current imagery. Revisions 2 through 25 have been redacted, due to edits by users who did not agree to the license change. The boundary may have had some improvements and corrections through those edits. Improved or otherwise, those edits are gone. Revision 26 shows that the redaction bot cleaned out the data that we were no longer entitled to keep. That left the way without tags. R27 in 2012 appears not to have directly affected the way. It may have edited an intersecting way? It was a large changeset. R28 in 2013 added the maritime tag you report. The maritime tag alone, is an unusual form. I don't think that it would be considered complete, unless combined with the tags of the parent relations. When compared with the 'bot-drawn 12nm maritime boundary, this way appears to be incorrect. It just doesn't seem to be far enough offshore to be a maritime boundary. When compared to http://www.openstreetmap.org/way/115038287 (from 2011, and a canvec import) the '485 way appears low resolution and poorly aligned. So there are are multiple imported boundaries here. Each were the probably best available at the time. Neither are perfect, and now the appear to somewhat duplicate each other, given the parent relations of '485. Hope that helps a bit. ___ Talk-ca mailing list Talk-ca@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk-ca___ Talk-ca mailing list Talk-ca@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk-ca