Wow thanks Bratillf, did you come up with that? That's really amazing. You mentioned pixels, in this equation are the X and Y's still just lat and lng coords?
Ben, The routes are for Byways.org I they aren't always consistent with google maps routes. The Net Duck On Apr 3, 6:44 am, bratliff <[email protected]> wrote: > On Apr 3, 12:07 am, The Net Duck <[email protected]> wrote: > > > > > > > HI > > I would like to be able to do two things and I don't know if it's > > possible with google maps api or if I need to build something myself. > > > thing 1) > > I would like to be able to "thin out" coordinates on a poly line > > based on zoom level. This is because I don't need the amount of detail > > when I'm zoomed out and am serving this as a mobile friendly site so > > would like to use as little processes as possible. > > > thing 2) > > I have many different polylines (I call them routes), and would > > like to only draw a polyline based on my maps "bounds". Is there a way > > to only draw a line this way? or is this something that I need to do > > by checking the coords that go into the creation of my polylines > > agents some "bounds" objects etc. > > > Thanks so much! > > - The Net Duck > > PolyCluster uses the following to perform point reduction: > > x=l.x[i+1]-l.x[i-1]; > y=l.y[i+1]-l.y[i-1]; > > z=x*(l.y[i]-l.y[i+1]+l.y[i]-l.y[i-1])-y*(l.x[i]-l.x[i+1]+l.x[i]- > l.x[i-1]); > > z=(z*z)/(x*x+y*y); > > where "z" is the square of the number of pixels away from the > "interpolation" line connecting the two immediate neighbors. You can > discard points for which "z" is less than the square of some > threshold. By using pixels rather than Lat/Lon coordinates, > projection distortion is avoided. The X & Y deltas are given the same > weight. > > It is much quicker than Douglas-Peucker because it is non-recursive. > It can be done in a single pass. It is symmetric which means it > discards the same points in either direction. If two polys share a > common boundary, it will not produce gaps and/or overlaps. Douglas- > Peucker was designed for polylines but not for polygons. > > You can see several demos at: > > http://www.polyarc.us > > An improved "US Highways" demo will be available soon. -- You received this message because you are subscribed to the Google Groups "Google Maps JavaScript API v3" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/google-maps-js-api-v3?hl=en.
