|

Mapnik maps offset by a few meters

View: New views

4 Messages — Rating Filter: Alert me

	Mapnik maps offset by a few meters by enigma2176 :: Rate this Message: Reply to Author \| View Threaded \| Show Only this Message I recently upgraded the OS on my GPS computer and I am seeing a problem with mapnik maps. No matter how I load the data in osm2pgsql the maps in GPSDrive are off by about 10 meters to the north and 10 meters to the west. My GPS position, as well as tracks, POIs, waypoints, etc. are all displaced on the map by a few meters. I am using the latest SVN for GPSDrive, mapnik 0.6.0 and the OSM tools are from SVN. I have seen the issue where the no projection was used causing positions to be off by many kilometers, but this off by a few meters issue is a new one for me. Has osm2pgsql changed the projection they use like described here: http://lists.gpsdrivers.org/pipermail/gpsdrive/2008-September/001420.html ? Do I need to use an older version of mapnik or osm2pgsql to be compatible with GPSDrive? I am seeing this issue on 2 different computers so I don't think it is unique, is anyone else seeing anything like this? _______________________________________________ GPSdrive mailing list GPSdrive@... http://lists.gpsdrivers.org/mailman/listinfo/gpsdrive
	Re: Mapnik maps offset by a few meters by hamish_b :: Rate this Message: Reply to Author \| View Threaded \| Show Only this Message Enigma wrote: > I recently upgraded the OS on my GPS > computer and I am seeing a problem with mapnik maps. No > matter how I load the data in osm2pgsql the maps in GPSDrive > are off by about 10 meters to the north and 10 meters to the > west. My GPS position, as well as tracks, POIs, waypoints, > etc. are all displaced on the map by a few meters. I am > using the latest SVN for GPSDrive, mapnik 0.6.0 and the OSM > tools are from SVN. I have seen the issue where the no > projection was used causing positions to be off by many > kilometers, but this off by a few meters issue is a new one > for me. Has osm2pgsql changed the projection they use like > described here: http://lists.gpsdrivers.org/pipermail/gpsdrive/2008-September/001420.html > ? to be technical, I think that is a matter of datum transform rather than map projection. > Do I need to use an older version of mapnik or osm2pgsql > to be compatible with GPSDrive? I am seeing this issue on > 2 different computers so I don't think it is unique, is > anyone else seeing anything like this? I don't know if it applies to Mapnik support, but see this bug report: http://sourceforge.net/tracker/?func=detail&aid=2203405&group_id=148048&atid=770280 what map scale? is it a constant 10m to N+W all over the map for all maps? Hamish _______________________________________________ GPSdrive mailing list GPSdrive@... http://lists.gpsdrivers.org/mailman/listinfo/gpsdrive
	Re: Mapnik maps offset by a few meters by enigma2176 :: Rate this Message: Reply to Author \| View Threaded \| Show Only this Message On Thu, Apr 30, 2009 at 5:00 AM, Hamish <hamish_b@...> wrote: Enigma wrote: > I recently upgraded the OS on my GPS > computer and I am seeing a problem with mapnik maps. No > matter how I load the data in osm2pgsql the maps in GPSDrive > are off by about 10 meters to the north and 10 meters to the > west. My GPS position, as well as tracks, POIs, waypoints, > etc. are all displaced on the map by a few meters. I am > using the latest SVN for GPSDrive, mapnik 0.6.0 and the OSM > tools are from SVN. I have seen the issue where the no > projection was used causing positions to be off by many > kilometers, but this off by a few meters issue is a new one > for me. Has osm2pgsql changed the projection they use like > described here: http://lists.gpsdrivers.org/pipermail/gpsdrive/2008-September/001420.html > ? to be technical, I think that is a matter of datum transform rather than map projection. I'm no cartographer - I'll take your word on that. > Do I need to use an older version of mapnik or osm2pgsql > to be compatible with GPSDrive? I am seeing this issue on > 2 different computers so I don't think it is unique, is > anyone else seeing anything like this? I don't know if it applies to Mapnik support, but see this bug report: http://sourceforge.net/tracker/?func=detail&aid=2203405&group_id=148048&atid=770280 what map scale? is it a constant 10m to N+W all over the map for all maps? It looks to be constant. I first noticed it at close scales but if I zoom out the offset is still there. It doesn't look like it gets bigger with the wider scales - it stays at about 10m offset. I'm fairly sure that it is not in the actual data because I was using the same extracts for my old installation that was displaying correctly. I am loading some data for a slightly lower latitude right now to see if the behavior changes at all. Josh Hamish _______________________________________________ GPSdrive mailing list GPSdrive@... http://lists.gpsdrivers.org/mailman/listinfo/gpsdrive _______________________________________________ GPSdrive mailing list GPSdrive@... http://lists.gpsdrivers.org/mailman/listinfo/gpsdrive
	Re: Mapnik maps offset by a few meters by enigma2176 :: Rate this Message: Reply to Author \| View Threaded \| Show Only this Message Just to follow up on this, it looks like the problem is with the actual data - I can reproduce the problem using the OSM website and renderers other than mapnik. It doesn't look like the data has changed for some time, so my memories of an accurate mapnik map for my neighborhood must have been a figment of my imagination. _______________________________________________ GPSdrive mailing list GPSdrive@... http://lists.gpsdrivers.org/mailman/listinfo/gpsdrive