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<div class="moz-cite-prefix">On 31/01/2015 1:47 AM, SomeoneElse
wrote:<br>
</div>
<blockquote cite="mid:54CB9980.1040304@atownsend.org.uk" type="cite">
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<div class="moz-cite-prefix">On 30/01/2015 14:12, St Niklaas
wrote:<br>
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<blockquote cite="mid:DUB123-W328ECBE7EBA4C481A3A6AB9A310@phx.gbl"
type="cite">
<div dir="ltr">> From: François Lacombe <a
moz-do-not-send="true" class="moz-txt-link-rfc2396E"
href="mailto:fl.infosreseaux@gmail.com"><fl.infosreseaux@gmail.com></a><br>
> <br>
> Since OSM editing tools aren't AutoCAD you can't be 100%
precise on the<br>
> geometry.<br>
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</blockquote>
<br>
Exactly so.<br>
<br>
<blockquote cite="mid:DUB123-W328ECBE7EBA4C481A3A6AB9A310@phx.gbl"
type="cite">
<div dir="ltr"><br>
<p class="MsoNormal" style="margin: 0cm 0cm 10pt;"><span
style="font-family:
"Calibri","sans-serif";
mso-ansi-language: EN-US;" lang="EN-US">Francois if you’re
using JOSM you’re be able to work up till 0,06 - 0,04
=0,02 m accuracy </span></p>
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</blockquote>
<br>
No. Unless you can measure accuracy on the ground to that level
of precision, you simply can't*. <br>
</blockquote>
<br>
And you should not use anything, AutoCAD included, to enter data at
a greater precision (accuracy) than what is available. Unfortunately
the data is stored as being absolutely accurate and precise so if
the end user is so inclined they could try to use it as such. They
would quickly be disappointed with OSM! OSM is not a source of
absolute accuracy.<br>
<br>
<br>
<div class="moz-cite-prefix">On 31/01/2015 1:47 AM, SomeoneElse
wrote:<br>
</div>
<blockquote cite="mid:54CB9980.1040304@atownsend.org.uk" type="cite">A
good rule of thumb for OSM is "don't try and map more accurately
than your sources". If you only have aerial imagery, or only have
a few GPS traces, don't try and map every last hedgerow, since you
simply don't know how accurate the sources that you're working
from are. Instead, go out and collect more data. For example,
once you know how aerial imagery compares to lots of GPS traces
(and vice-versa - GPS traces can have a systematic offset due to
terrain and even "what side of a road people are allowed to walk
down") you're in a much better position to contribute.</blockquote>
<br>
Here I diverge. If the hedgerow is an improtant part of the
landscape then I'd map it .. even if it is not at your required
level of 'accuracy'. Reason: it is the relationship between the
objects on the map that is important rather than the absolute
accuracy of any one object. If the relationship between the objects
is representative of what is on the ground then it conveys usefull
information to the end user and should be mapped. <br>
<br>
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