<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0//EN" "http://www.w3.org/TR/REC-html40/strict.dtd"><html><head><meta name="qrichtext" content="1" /><style type="text/css">p, li { white-space: pre-wrap; }</style></head><body style=" font-family:'Sans Serif'; font-size:10pt; font-weight:400; font-style:normal;">On Fri, 12 Jun 2009, Delta Foxtrot wrote:<br>
> > I've come to the realisation that every road (and<br>
> > everything that was placed in reference to the roads) in the<br>
> > suburb where I live is out by about 8-10m. Much of<br>
> > Brisbane's road system seems to have been traced off the<br>
> > Yahoo imagery, apparently without aligning it to fixed<br>
> > points before hand.<br>
><br>
> 8-10m isn't that much of an error to be honest. There really isn't any such<br>
> thing as perfect data if you are using consumer grade equipment of any<br>
> sort, things will improve over the next 10 to 20 years with other<br>
> constellations of GPS like sats starting to broadcast, but until then 10m<br>
> is as good as it gets for the most part for most things unless you spend a<br>
> lot of time getting very very accurate positioning.<br>
<p style="-qt-paragraph-type:empty; margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;"><br></p>There are definitely suburbs in SW Sydney where we have seen the same - the photos have not been aligned with any known points.<br>
There are tricks in JOSM for moving these areas en masse - can't confirm for any other editor.<br>
<p style="-qt-paragraph-type:empty; margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;"><br></p>I think that often the amount was greater than 10 metres.<br>
But we aren't making a perfect plan of the area - we are making a map, and to me it is an aid to navigation, so the exact placement is not as important as the relative positions of the objects.<br>
<p style="-qt-paragraph-type:empty; margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;"><br></p>But we can improve the accuracy over time as DF notes.<br>
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