On Sep 27, 3:55 pm, WeatherPhilip <[email protected]> wrote:
> When you create a GPolygon and fill it, the area inside *is* a > specific area on the surface of the earth. No. A GPolygon is a 2D representation of a 3D area. Under the Mercator projection, the pole is not a point, but a line. To convince yourself, try plotting two markers on the pole, but with different longitudes. var p1 = new GLatLng(90,20); var marker1 = new GMarker(p1); map.addOverlay(marker1) var p2 = new GLatLng(90,70); var marker2 = new GMarker(p2); map.addOverlay(marker2) Those two markers have latitude 90, so they should be on the same point, right? They aren't, because as John said, the poles cannot be calculated. -- Marcelo - http://maps.forum.nu -- > There is no problem near > the north pole. In order to draw the polygon on a planar map, then > each point inside the polygon needs to be mapped onto the plane. > *Some* of these points fall outside the area which is representable on > a google map. > > What I suspect happens is that the maps code does the fill after > mapping the polygon outline on the planar map. The problem with this > approach is that it doesn't provide the same answer due to the fill > algorithm used. > > Philip > > On Sep 27, 12:31 am, "Maps.Huge.Info (Maps API Guru)" > > <[email protected]> wrote: > > The maximum magnitude of latitude that can be handled by World > > Mercator is around 86 degrees. Anything greater than that is subject > > to nearly infinite error due to the projection characteristics. > > > The problem is easy to understand if you think about what World > > Mercator does. The idea with this projection is that latitude and > > longitude lines are perpendicular to each other regardless of where > > they lie on the globe. In reality, longitude lines converge as the > > latitude increases, at the pole, you can put your foot on every > > longitude line, so the error in this projection goes to infinity at > > that point. Around 86 degrees, the error is so great that the > > projection becomes useless. > > > -John Coryat > > >http://maps.huge.info > > >http://www.usnaviguide.com > > >http://www.zipmaps.net --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Google Maps API" 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-api?hl=en -~----------~----~----~----~------~----~------~--~---
