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<font face="Arial, Helvetica">Hello Steve,<br><br>
Thanks for that clarification, I think I get the distinctions. Are
you saying that the image shift is not saved, it is only evident on the
local computer? So other users would not see that change, is that
correct?<br><br>
However, there is an image shift database which implies that the shifts
are permanent and could be documented.<br><br>
Yes, I was aware of the off-nadir angle problem but didn't realize it was
an issue here. As you know, the "best" part of the image
is near the center, the off-nadir approach is like looking past the far
edge of the photo! Necessary in this case, I suppose.<br><br>
Sorry to be a bit obtuse, but this image shifting practice is new to
me.<br><br>
<x-tab> </x-tab>Thanks
again, Cheers . . . . . . . . Spring<br><br>
<br><br>
</font>At 09-05-2015 11:03 Saturday, Steve Bower wrote:<br>
<blockquote type=cite class=cite cite="">Spring,<br>
When I talk about "moving the imagery" that is only to align it
with Bing imagery as I work in a very localized area, in order to confirm
that the features are (roughly) correctly located, relative to Bing. It
does not change the geo-referencing of the underlying data for other
users - it is only revising it for my display. I expect that how you
understood it, but in case that wasn't clear. <br><br>
I haven't personally digitized anything from the DG imagery. I have only
used it to help with interpretation where the Bing imagery is poor (low
res or cloudy). But others may be locating features from the DG imagery -
hopefully only experienced mappers with careful reference to better
geo-rectified imagery ("hopefully" being the aspect that gives
us all concern, of course).<br><br>
I fully agree this is not "best practice" for digital mapping -
it's "best available" within resource constraints for crisis
response.<br><br>
By the way, you may already be very familiar with this, but the elevation
aspect of ortho-rectification is described here (see image at top-right):
<a href="http://en.wikipedia.org/wiki/Orthophoto">
http://en.wikipedia.org/wiki/Orthophoto</a>. Or see the first image in
this page:
<a href="http://www.kevinroper.org/portfolio/">
http://www.kevinroper.org/portfolio/</a> . These explain why the more
severe off-nadir angle causes greater location distortion, more difficult
to correct for. <br><br>
<br><br>
On Sat, May 9, 2015 at 10:30 AM, Kevin Bullock
<<a href="mailto:kbullock@digitalglobe.com">
kbullock@digitalglobe.com</a>> wrote:<br>
<dl>
<dd>>>Does Digital Globe supply Bing images? Just curious, they
are always referred to as different products.<br><br>
<dd>Yes, Microsoft licenses DigitalGlobe imagery for many parts of the
world, you’ll notice the attribution in the Bing Maps platform. In
various threads, I’ve seen Bing imagery “versus” DigitalGlobe
imagery, and that is usually a contradiction. The proper way of
characterizing it is: DigitalGlobe imagery through the Bing platform
versus DigitalGlobe imagery being made available during this crisis.
<a href="https://www.digitalglobe.com/partners/platform-partners/microsoft">
https://www.digitalglobe.com/partners/platform-partners/microsoft</a><br>
<br>
<dd>Cheers, Kevin<br><br>
<br>
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