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