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i wrote a josm plugin that does all the math and marks the border of
every canvec tile<br>
some of the tiles match my grid perfectly, and match eachother with
no overlap or gap<br>
other tiles are offset slightly and dont fit the grid or eachother<br>
<br>
by checking the grid in my plugin, i can tell which node is in the
'correct' spot, because the canvec edges are always a certain
fraction of a degree<br>
<br>
<br>
On 01/30/2012 06:36 PM, Samuel Longiaru wrote:
<blockquote cite="mid:1327962999.2272.20.camel@SamsLinuxMachine"
type="cite">
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But which is the "right"position? When one is given to be 3 cm's
off the other, neither is more accurate, given the data collection
technique. I think you are beyond the accuracy of the data
themselves at that level. While merging and then combining a
stream or a road that crosses a tile boundary, trying to decide
which node is more "accurate" is one of those questions best asked
only during periods of intensive navel contemplation. Take either
one. The precision of the data exceed their accuracy I would
guess by several orders of magnitude. Is the next node along the
way mapped to 3 cm accuracy? Or the next, or the next? No. Here
is an example where "good enough" is TRULY "good enough". It's
all the science can bear. <br>
<br>
Sam<br>
<br>
<br>
<br>
-----Original Message-----<br>
<b>From</b>: michael bishop <<a moz-do-not-send="true"
href="mailto:michael%20bishop%20%3cclever@nbnet.nb.ca%3e">clever@nbnet.nb.ca</a>><br>
<b>To</b>: Talk-CA OpenStreetMap <<a moz-do-not-send="true"
href="mailto:Talk-CA%20OpenStreetMap%20%3ctalk-ca@openstreetmap.org%3e">talk-ca@openstreetmap.org</a>><br>
<b>Subject</b>: Re: [Talk-ca] canvec data offset<br>
<b>Date</b>: Mon, 30 Jan 2012 18:01:04 -0400<br>
<br>
yeah, thats what i had to do for every node<br>
but part is the issue there, is that when i merge 2 nodes, it
doesnt always go to the 'right' position'<br>
need to manualy select them in the right order to make it go in
the right direction, it seems more like an error in the canvec
data then an extra step i need to do on every tile<br>
almost looks like floating point rounding errors, but not sure why
some tiles are ok and others arent<br>
<br>
<br>
On 01/30/2012 05:56 PM, Samuel Longiaru wrote: <br>
<blockquote type="CITE"> <br>
Have you tried just zooming back a bit in JOSM and merging
them? It's part of my stitching process for each tile. I've
never had a merge refused because of a 3 cm difference (but, of
course I've never looked that closely to see how far apart they
were actually). We're dealing with precision here... not
accuracy at that level.<br>
<br>
Sam<br>
<br>
-----Original Message-----<br>
<b>From</b>: michael bishop <<a moz-do-not-send="true"
href="mailto:michael%20bishop%20%3cclever@nbnet.nb.ca%3e">clever@nbnet.nb.ca</a>><br>
<b>To</b>: Samuel Longiaru <<a moz-do-not-send="true"
href="mailto:Samuel%20Longiaru%20%3clongiaru@shaw.ca%3e">longiaru@shaw.ca</a>><br>
<b>Subject</b>: Re: [Talk-ca] canvec data offset<br>
<b>Date</b>: Mon, 30 Jan 2012 17:42:42 -0400<br>
<br>
yeah, its not much, but its enough to screw up josm when trying
to combine things between the 2 tiles<br>
have to fix each node on the border one by one, no real patern
to which direction they are shifted<br>
even along a solid line (the edge of the tile), the nodes are
going up&down and zig-zagging across the edge<br>
<br>
<br>
On 01/30/2012 05:31 PM, Samuel Longiaru wrote: <br>
<blockquote type="CITE"> <br>
I can hardly put my finger to my nose to within .03 meters...
and that's not even drunk. :)<br>
<br>
Sam L.<br>
Kamloops<br>
<br>
<br>
<br>
-----Original Message-----<br>
<b>From</b>: michael bishop <<a moz-do-not-send="true"
href="mailto:michael%20bishop%20%3cclever@nbnet.nb.ca%3e">clever@nbnet.nb.ca</a>><br>
<b>To</b>: Talk-CA OpenStreetMap <<a moz-do-not-send="true"
href="mailto:Talk-CA%20OpenStreetMap%20%3ctalk-ca@openstreetmap.org%3e">talk-ca@openstreetmap.org</a>><br>
<b>Subject</b>: [Talk-ca] canvec data offset<br>
<b>Date</b>: Mon, 30 Jan 2012 17:11:27 -0400<br>
<br>
<pre>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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