Re: [Talk-ca] canvec data offset
Bonjour Frank, The problem is not related to a NAD27-NAD83 conversion. With Michael's example, I am now sure that the problem is related to the quadtree clipper. I must find a way to round quadtree's tiles coordinates to a proper value. Thanks to Michael Best regard, Daniel -Original Message- From: Frank Steggink [mailto:stegg...@steggink.org] Sent: January 31, 2012 11:56 To: talk-ca@openstreetmap.org Subject: Re: [Talk-ca] canvec data offset I've seen some of these deviations as well during Canvec import. Because they are so small (< 1 meter), I just decided to glue the polygons together, so any slivers are gone. It is inconvenient though. Could it be related to that some sheets were originally still in NAD27, instead of NAD83 (which is approximately WGS84, as used by OSM)? Frank On 31-1-2012 15:06, michael bishop wrote: > the south east corner of 021O10.0 is at 47.534 by -66.7500013 the > north east corner of 021O07.1 (should be exact same node), is at > 47.500 by -66.750 the exact offset differs from corner to > corner, some are off more then others, some are off in a different > direction > > > On 01/31/2012 08:11 AM, Bégin, Daniel wrote: >> Bonjour, >> >> I'll have a look to see if I can do something for it in the next >> release. >> >> I suspect that might be caused by data resolution. Lat and Lon are >> stored in decimal degrees with 7 digits precision (48.1234567). The >> 7th digit will provide a precision around 0.001 meter. The 6th digit >> a precision around 0.027 meter witch look like your 0.03 meter. >> >> Cheers >> Daniel >> >> -Original Message- >> From: michael bishop [mailto:cle...@nbnet.nb.ca] >> Sent: January 30, 2012 16:11 >> To: Talk-CA OpenStreetMap >> Subject: [Talk-ca] canvec data offset >> >> ive been working with canvec for a few days now, and ive noticed some >> of the data is offset by 0.03 meters its not matching up with nearby >> tiles >> >> for example 021O10 doesnt match up with 021O07 >> >> ive noticed the problem on other tiles aswell, but didnt think to >> write them down >> >> >> ___ >> Talk-ca mailing list >> Talk-ca@openstreetmap.org >> http://lists.openstreetmap.org/listinfo/talk-ca >> > > > ___ > Talk-ca mailing list > Talk-ca@openstreetmap.org > http://lists.openstreetmap.org/listinfo/talk-ca > ___ Talk-ca mailing list Talk-ca@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-ca ___ Talk-ca mailing list Talk-ca@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-ca
Re: [Talk-ca] canvec data offset
I've seen some of these deviations as well during Canvec import. Because they are so small (< 1 meter), I just decided to glue the polygons together, so any slivers are gone. It is inconvenient though. Could it be related to that some sheets were originally still in NAD27, instead of NAD83 (which is approximately WGS84, as used by OSM)? Frank On 31-1-2012 15:06, michael bishop wrote: the south east corner of 021O10.0 is at 47.534 by -66.7500013 the north east corner of 021O07.1 (should be exact same node), is at 47.500 by -66.750 the exact offset differs from corner to corner, some are off more then others, some are off in a different direction On 01/31/2012 08:11 AM, Bégin, Daniel wrote: Bonjour, I'll have a look to see if I can do something for it in the next release. I suspect that might be caused by data resolution. Lat and Lon are stored in decimal degrees with 7 digits precision (48.1234567). The 7th digit will provide a precision around 0.001 meter. The 6th digit a precision around 0.027 meter witch look like your 0.03 meter. Cheers Daniel -Original Message- From: michael bishop [mailto:cle...@nbnet.nb.ca] Sent: January 30, 2012 16:11 To: Talk-CA OpenStreetMap Subject: [Talk-ca] canvec data offset ive been working with canvec for a few days now, and ive noticed some of the data is offset by 0.03 meters its not matching up with nearby tiles for example 021O10 doesnt match up with 021O07 ive noticed the problem on other tiles aswell, but didnt think to write them down ___ Talk-ca mailing list Talk-ca@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-ca ___ Talk-ca mailing list Talk-ca@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-ca ___ Talk-ca mailing list Talk-ca@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-ca
Re: [Talk-ca] canvec data offset
the south east corner of 021O10.0 is at 47.534 by -66.7500013 the north east corner of 021O07.1 (should be exact same node), is at 47.500 by -66.750 the exact offset differs from corner to corner, some are off more then others, some are off in a different direction On 01/31/2012 08:11 AM, Bégin, Daniel wrote: Bonjour, I'll have a look to see if I can do something for it in the next release. I suspect that might be caused by data resolution. Lat and Lon are stored in decimal degrees with 7 digits precision (48.1234567). The 7th digit will provide a precision around 0.001 meter. The 6th digit a precision around 0.027 meter witch look like your 0.03 meter. Cheers Daniel -Original Message- From: michael bishop [mailto:cle...@nbnet.nb.ca] Sent: January 30, 2012 16:11 To: Talk-CA OpenStreetMap Subject: [Talk-ca] canvec data offset ive been working with canvec for a few days now, and ive noticed some of the data is offset by 0.03 meters its not matching up with nearby tiles for example 021O10 doesnt match up with 021O07 ive noticed the problem on other tiles aswell, but didnt think to write them down ___ Talk-ca mailing list Talk-ca@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-ca ___ Talk-ca mailing list Talk-ca@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-ca
Re: [Talk-ca] canvec data offset
Bonjour, I'll have a look to see if I can do something for it in the next release. I suspect that might be caused by data resolution. Lat and Lon are stored in decimal degrees with 7 digits precision (48.1234567). The 7th digit will provide a precision around 0.001 meter. The 6th digit a precision around 0.027 meter witch look like your 0.03 meter. Cheers Daniel -Original Message- From: michael bishop [mailto:cle...@nbnet.nb.ca] Sent: January 30, 2012 16:11 To: Talk-CA OpenStreetMap Subject: [Talk-ca] canvec data offset ive been working with canvec for a few days now, and ive noticed some of the data is offset by 0.03 meters its not matching up with nearby tiles for example 021O10 doesnt match up with 021O07 ive noticed the problem on other tiles aswell, but didnt think to write them down ___ Talk-ca mailing list Talk-ca@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-ca ___ Talk-ca mailing list Talk-ca@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-ca
