<div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote">On Fri, Oct 23, 2015 at 11:19 AM, Moritz Lennert <span dir="ltr"><<a href="mailto:mlennert@club.worldonline.be" target="_blank">mlennert@club.worldonline.be</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><span>On 23/10/15 10:56, Johannes Radinger wrote:<br>
</span><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><span>
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<br>
On Fri, Oct 23, 2015 at 10:17 AM, Moritz Lennert<br></span><div><div>
<<a href="mailto:mlennert@club.worldonline.be" target="_blank">mlennert@club.worldonline.be</a> <mailto:<a href="mailto:mlennert@club.worldonline.be" target="_blank">mlennert@club.worldonline.be</a>>> wrote:<br>
<br>
On 22/10/15 16:25, Johannes Radinger wrote:<br>
<br>
Dear GRASS users,<br>
<br>
Today I wanted to try the georectification tool g.gui.gcp in<br>
GRASS 7 for<br>
the first time. I was basically following the description on the<br>
GRASS<br>
wiki (<a href="https://grasswiki.osgeo.org/wiki/Georeferencing" rel="noreferrer" target="_blank">https://grasswiki.osgeo.org/wiki/Georeferencing</a>). In<br>
particular, I<br>
have a photograph from my camera with known reference points which I<br>
load into an unprojected XY location. My target location should<br>
also be<br>
a XY location as the picture is taken from a "virtual" coordinate<br>
system. Inside my target XY-location I try to open g.gui.gcp and<br>
select<br>
raster, and the location and mapset where my photograph is<br>
stored. When<br>
I want to click next I get following error/message: "You must<br>
select a<br>
valid location and mapset in order to continue" and I can't<br>
proceed with<br>
the rectification. Just this GUI message appears, no<br>
error/warning in<br>
the grass console etc. I am puzzled how to interpret that? What<br>
is wrong<br>
with the location/mapset? The mapset I've selected is existing<br>
(I can<br>
select it from the dropdown menu). I tried to select any other<br>
location/mapset but receive always the same message.<br>
<br>
<br>
<br>
Georectification is for georeferencing to a projected system. It<br>
does not make sense to georeference to an XY-location.<br>
<br>
I see two options for you:<br>
<br>
- Import you image directely into the target region and use r.region<br>
to adjust its boundary coordinates<br>
- Define your own projection system to fit your needs.<br>
<br>
<br>
So far as I understand georectification and orthorectification in<br>
particular is to rectify a picture/photo/image based on spatially<br>
defined ground control points which might not be done by just adjusting<br>
the boundary coordinates. BTW I also tried the European LAEA coordinate<br>
system (EPSG 3035) as a target location which is not working either here<br>
in my machine/setup (same message as already mentioned). Here<br>
(<a href="https://www.dropbox.com/s/snjzd8eu7b8115k/2015-10-22%2015.26.30.jpg?dl=0" rel="noreferrer" target="_blank">https://www.dropbox.com/s/snjzd8eu7b8115k/2015-10-22%2015.26.30.jpg?dl=0</a>)<br>
you can find a a photo (*.jpg) which is an "areal" photo with known 3d<br>
coordinates for the single points (ground control points). I think this<br>
example clarifies and illustrates what I intend to do and why the target<br>
system can also be a XY location in my opinion. A rectification of this<br>
image should make the lines of the grid more or less parallel. Or do I<br>
get something completely wrong?<br>
</div></div></blockquote>
<br>
Actually, I was wrong: I don't get any complaint trying to use g.gui.gcp to georectify from XY to XY. So there seems to be an issue with your XY locations.<br>
<br>
Have you tried recreating the locations from scratch ?</blockquote><div><br></div><div>Your results look really reasonable.... that's what I was looking for...</div><div><br></div><div>Actually, both XY locations are created from scratch (via the location wizzard)</div><div>I get following output for both XY locations: </div><div><br></div><div>g.proj -p </div><div>XY location (unprojected)</div><div><br></div><div>I tried to start the GCP manager from within different other locations (e.g. laea, datum: etrs89) and selecting different source location (e.g. WGS84)....however I always get the same message. So I guess this is not specifically related to my location but rather to the GCP manager/WX GUI? As I don't get an error message it is difficult to judge what is going wrong in my case...</div><div><br></div><div>I just looked up the source code and the error message seems to be related to follwoing line:</div><div><a href="https://trac.osgeo.org/grass/browser/grass/branches/releasebranch_7_0/gui/wxpython/gcp/manager.py#L399">https://trac.osgeo.org/grass/browser/grass/branches/releasebranch_7_0/gui/wxpython/gcp/manager.py#L399</a><br></div><div>As far as I understand, this error message is only given if no location/mapset is provided; however that is not the case here. Maybe my selection of the location/mapset via the GUI does not get parsed further....?</div><div><br></div><div>Strange that orthorectification from one XY to antother XY location works on other machines but not on mine.</div><div><br></div><div>PS: As an important side note: I am working on Ubuntu which is installed on a virtual machine (VMWare) on our server. I remotely connect to this virtual machine via RDP. </div><div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><span><font color="#888888"><br>
<br>
Moritz<br>
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