Re: [OSM-talk] maritime borders
Robin Paulson wrote: i should say, i'm no expert on this, but the article i was talking about mentioned land cannons, which probably had none of the weight constraints that ship-based cannons did. American Civil War-era howitzers had a range of over 1.83 km, and that was considered a long way for the time: http://en.wikipedia.org/wiki/Cannon There is no way a 14th century cannon of any sort could fire 22km. Gerv ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk
Re: [OSM-talk] maritime borders (was: administrative boundaries and is_in)
On 13/01/2008, Robin Paulson [EMAIL PROTECTED] wrote: i'll start a wiki page. anyone here have any experience with drawing libraries? i'm sure we can do this by re-using something that's already there ok, here we go. i've put in some rough details of the method i suggested earlier. if anyone can expand on it (maths for converting lat/lon to distance would be useful), or add any other proposals, that would be great http://wiki.openstreetmap.org/index.php/Maritime_borders ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk
Re: [OSM-talk] maritime borders
Robin Paulson wrote the following on 13/01/2008 21:50: On 13/01/2008, Robin Paulson [EMAIL PROTECTED] wrote: i'll start a wiki page. anyone here have any experience with drawing libraries? i'm sure we can do this by re-using something that's already there ok, here we go. i've put in some rough details of the method i suggested earlier. if anyone can expand on it (maths for converting lat/lon to distance would be useful), or add any other proposals, that would be great Maybe we are overcomplicating this. Mapping these borders programmatically based on the existing coastline which may already be a little inaccurate where based on PGS data will at best give an approximation even if you take into account all the exceptions listed here http://en.wikipedia.org/wiki/Territorial_waters#Special_cases. Surely what would be best is to find a dataset that contains the actual international borders based on the UN convention. I'm still looking for a source but surely they must be public other wise it would be a bit tricky to enforce your territorial waters if no one else knows exactly where the line is or if everyone is using a slightly different method of calculating it. Does anyone know if the CIA data that has been used for land borders also contains sea borders? Or is there any other PD sources available? What do maritime gps systems use? Cheers rcr ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk
Re: [OSM-talk] maritime borders
Rob Reid wrote: Surely what would be best is to find a dataset that contains the actual international borders based on the UN convention. I'm still looking for a source but surely they must be public other wise it would be a bit tricky to enforce your territorial waters if no one else knows exactly where the line is or if everyone is using a slightly different method of calculating it. Check out the FAQ on the UN site, looks like they charge for these things http://www.un.org/Depts/los/LEGISLATIONANDTREATIES/frequently_asked_questions.htm Igor ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk
Re: [OSM-talk] maritime borders (was: administrative boundaries and is_in)
On Jan 12, 2008 11:32 AM, Igor Brejc [EMAIL PROTECTED] wrote: That would be an interesting thing to implement. It would involve creating a union of circles (with radius of 12 NM) and then determining the border of that union. If only I had the time... :) I thin you'd approach it from the other way. Take a 12nm circle and push it against the coastline so it touches at a point. Then roll it along with the centre tracing a line, forming either an arc where it rotates around a point, or a straight line as it slides along an edge. Have a nice day, -- Martijn van Oosterhout [EMAIL PROTECTED] http://svana.org/kleptog/ ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk
Re: [OSM-talk] maritime borders (was: administrative boundaries and is_in)
On 12/01/2008, Igor Brejc [EMAIL PROTECTED] wrote: Just as a curiosity: 12 NM was chosen because it it the farthest point a person can see from the shore (due to Earth's roundness). Or something like that :) according to wp, it was the range of a cannon in 14th c or something ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk
Re: [OSM-talk] maritime borders
Robin Paulson wrote: On 12/01/2008, Igor Brejc [EMAIL PROTECTED] wrote: Just as a curiosity: 12 NM was chosen because it it the farthest point a person can see from the shore (due to Earth's roundness). Or something like that :) according to wp, it was the range of a cannon in 14th c or something XIV c. ships would draw rather then carried a cannon that could shoot as far as 22.2 km. It must be something different. -- Było mi bardzo miło. Czwarta pospolita klęska, [...] Łukasz Już nie katolicka lecz złodziejska. (c)PP -- Sprawdz, ktore komorki sa najmodniejsze! Kliknij http://link.interia.pl/f1cd4 begin:vcard fn;quoted-printable:=C5=81ukasz Stelmach n;quoted-printable:Stelmach;=C5=81ukasz email;internet:[EMAIL PROTECTED] x-mozilla-html:FALSE version:2.1 end:vcard ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk
Re: [OSM-talk] maritime borders
On 13/01/2008, Lukasz Stelmach [EMAIL PROTECTED] wrote: according to wp, it was the range of a cannon in 14th c or something XIV c. ships would draw rather then carried a cannon that could shoot as far as 22.2 km. It must be something different. i should say, i'm no expert on this, but the article i was talking about mentioned land cannons, which probably had none of the weight constraints that ship-based cannons did. anyway, i digress ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk
Re: [OSM-talk] maritime borders (was: administrative boundaries and is_in)
On 12/01/2008, Martijn van Oosterhout [EMAIL PROTECTED] wrote: On Jan 12, 2008 11:32 AM, Igor Brejc [EMAIL PROTECTED] wrote: That would be an interesting thing to implement. It would involve creating a union of circles (with radius of 12 NM) and then determining the border of that union. If only I had the time... :) I thin you'd approach it from the other way. Take a 12nm circle and push it against the coastline so it touches at a point. Then roll it along with the centre tracing a line, forming either an arc where it rotates around a point, or a straight line as it slides along an edge. well, there are two elements to consider: ways, and points. ways are easy: as they are drawn a certain direction always (water on left, is that it?), we just create a set of ways that are 12 nautical miles to the left of each way. for points, yes, as igor says it's best to create a circle around each point, of 12 nautical miles radius. there must be some (CAD?) library for taking three inputs (two straight lines, a circle), and working out the necessary start and end point of the three items, so they form a continuous, smooth (i.e. tangential) line. then repeat for all point/line combinations i'll start a wiki page. anyone here have any experience with drawing libraries? i'm sure we can do this by re-using something that's already there ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk
