[Talk-ca] canvec data offset

[Frank Steggink]

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 47.5000034 by -66.7500013
> the north east corner of 021O07.1 (should be exact same node), is at 
> 47.5000000 by -66.7500000
> 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:clever at 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
>>
>>
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>
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