<div dir="ltr"><p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal;background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><span style="font-size:7pt;font-family:arial,sans-serif;color:rgb(80,0,80)">Thank you very much for responses. <span></span></span></p>
<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal;background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><span style="font-size:7pt;font-family:arial,sans-serif;color:rgb(80,0,80)"><span> </span></span></p>
<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal;background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><span style="font-size:7pt;font-family:arial,sans-serif;color:rgb(80,0,80)">I am ok with the output because I use raster
georeferencing for display purposes and will be done in conjunction with latest
satellite image. Actually, I got GCPs
from Google Earth image. The problem is when georeferenced image get loaded up on
QGIS it does not align with cadastre. I do not have a problem with topographic
maps as they do align; same applies to satellite images with map projection (old
and new). My main challenge is with historical aerial photo maps from NGI. I
only received images (jpeg) and flight plans from NGI with no .tfw file and struggling.
<span></span></span></p>
<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal;background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><span style="font-size:7pt;font-family:arial,sans-serif;color:rgb(80,0,80)"><span> </span></span></p>
<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal;background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><span style="font-size:7pt;font-family:arial,sans-serif;color:rgb(80,0,80)">With Thanks <span></span></span></p>
<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal;background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><span style="font-size:7pt;font-family:arial,sans-serif;color:rgb(80,0,80)"><span> </span></span></p>
<span style="font-size:7pt;line-height:115%;font-family:arial,sans-serif;color:rgb(80,0,80)">Jeff</span><br></div><div class="gmail_extra"><br><div class="gmail_quote">On 17 November 2016 at 08:47, Aslam Parker <span dir="ltr"><<a href="mailto:Aslam.Parker@drdlr.gov.za" target="_blank">Aslam.Parker@drdlr.gov.za</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hi<br>
<br>
Please let me clarify :)<br>
<br>
NGI standard orthorectification is a rigorous process that uses high resolution aerial imagery, post processed external orientation parameters, precise camera models, photo ground control, rigorous bundle block adjustment, digital elevation models and individual orthorectification, mosaicking, colour balancing and cutting into tiles, and finally compression.<br>
<br>
When I said we do it all the time, I was referring to numerous requests for add-hoc georeferencing of our historical imagery, especially for land restitution. As you are aware, our digital orthorimagery only dates back to 1990's but we have historical aerial imagery dating back to 1926. In this case we often use the rubber sheeting method, but are aware of its limitations. We are looking into software that is specifically suited for orthorectification of historical imagery using DEM and patch rectification.<br>
<br>
I trust that this clarifies matters.<br>
<span class="im HOEnZb"><br>
<br>
-----Original Message-----<br>
From: Africa [mailto:<a href="mailto:africa-bounces@lists.osgeo.org">africa-bounces@lists.<wbr>osgeo.org</a>] On Behalf Of Chris<br>
Sent: 17 November 2016 07:20 AM<br>
To: Africa local chapter discussions<br>
</span><div class="HOEnZb"><div class="h5">Subject: Re: [OSGeo Africa] Georeferencing or overlaying old aerial photograph with cadastre<br>
<br>
<br>
Morning Aslam ,<br>
<br>
Georeferencing by common points<br>
<br>
I believe you guys ( NGI / SG ) have a more advanced way of doing this<br>
whereby one ends up with a proper accurate geo-refeerenced orthophoto<br>
( orthorectified )<br>
<br>
I am curious ?<br>
<br>
CM<br>
<br>
<br>
<br>
On 16 Nov 2016 at 11:06, Aslam Parker wrote:<br>
<br>
> Hi Jeff<br>
<br>
> My colleague Muhammed Deal <<a href="mailto:Muhammed.Deal@drdlr.gov.za">Muhammed.Deal@drdlr.gov.za</a>> has a tutorial<br>
> that he can send you, we do this all the time on QGIS.<br>
<br>
> Please take note that if you do a georeferencing by common points,<br>
> this amounts to rubbersheet/transformation and does not create an<br>
> orthorectified imagery and the georeferencing will be approximate.<br>
<br>
<br>
<br>
> From: Africa [mailto:<a href="mailto:africa-bounces@lists.osgeo.org">africa-bounces@lists.<wbr>osgeo.org</a>] On Behalf Of Jeff<br>
> Ngwane Sent: 16 November 2016 12:17 PM To: Africa local chapter<br>
> discussions Subject: [OSGeo Africa] Georeferencing or overlaying old<br>
> aerial photograph with cadastre<br>
<br>
> Hi,<br>
<br>
> How to correctly georeference old aerial photograph (i.e 1972) for<br>
> purpose of being aligned with up to date cadastre on QGIS recent<br>
> versions? I have been trying but in vain. Please help me.<br>
<br>
> Thank<br>
<br>
> Jeff<br>
<br>
<br>
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