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 (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 (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
