Thanks for the reply Michael,<div>My concern was not so much about the imagery being out of date, as I only trace places that I am very familiar with albeit having visited a long time ago. I will be visiting a few places I have mapped soon and will be having my GPS switched on all the time. It generally has good accuracy +- 3m, so should be a good start to help correct any potential offset errors if any.</div>
<div><br></div><div>Regards </div><div class="gmail_extra"><br><br><div class="gmail_quote">On 8 December 2012 10:16, Michael S <span dir="ltr"><<a href="mailto:michael@elfu.de" target="_blank">michael@elfu.de</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF">
<div>Since I am also interested in this
discussion I'd like to crosspost my answer also to the talk
mailing list:<br>
<br>
Hello Gerhardus,<div class="im"><br>
<br>
>In the absence of immediate local presence, is tracing
acceptable and not wasted effort.<br>
<br></div>
Personally I only do aerial image mapping to a limited extent
because I fear that I will map wrong objects (e.g. nonexisting
buildings, roads) because of outdated bing images. I feel much
more comfortable to do bing mapping when I also do know the
surrounding by own survey.<br>
However, I would follow a pragmatic approach: E.g. If there is no
railway at all in the map, and you think that it is likely that
the railway is still there I would go for remote mapping.<br>
<br>
Offset Problem:<br>
Maybe you could compare objects already being mapped on a large
scale ( larger towns ) and only do large scale mapping like major
roads, but no micro mapping like lake boundaries on a 50 m scale
without having better offset information.<br>
<br>
Michael<br>
<br>
<br>
Am 01.12.2012 13:59, schrieb Gerhardus Geldenhuis:<br>
</div>
<blockquote type="cite"><div><div class="h5">Hi
<div>I have mainly been doing tracing of Bing images in far flung
corners of the world where I have been. However I have been
reading about offset problems with Bing imagery and was
wondering if this would all be wasted work? </div>
<div><br>
</div>
<div>I have mainly been doing work in Zimbabwe and South Africa
with work being classified as:</div>
<div>
<ul>
<li>Tracing and classing buildings</li>
<li>Making lake outlines more accurate. Lake Kariba as an
example is a bit rough and ready. This is mainly prep work
so I can add marinas and other amenities. </li>
<li>Tracing railway lines and roads in northern Zimbabwe.</li>
</ul>
<div><br>
</div>
<div>I might revisit a number of the places I have edited and
will then be able to get some GPS traces, building names etc
that I could use to compare offset with. But in the meantime
is there any other way to determine the offset of satellite
imagery?</div>
<div><br>
</div>
<div>So to summarize my questions:</div>
<div>
<ul>
<li>In the absence of immediate local presence, is tracing
acceptable and not wasted effort.</li>
<li>Is there a reliable way to determine offset in a
specific location without GPS track data</li>
</ul>
<div>Regards<br>
</div>
</div>
<div><br>
</div>
-- <br>
Gerhardus Geldenhuis<br>
</div>
<br>
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<br></blockquote></div><br><br clear="all"><div><br></div>-- <br>Gerhardus Geldenhuis<br>
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