[GRASS-user] Problems running g.gui.gcp

[Anna Petrášová]

On Oct 23, 2015 6:04 AM, "Johannes Radinger" <johannesradinger at gmail.com>
wrote:
>
>
>
> On Fri, Oct 23, 2015 at 11:19 AM, Moritz Lennert <
mlennert at club.worldonline.be> wrote:
>>
>> On 23/10/15 10:56, Johannes Radinger wrote:
>>>
>>>
>>>
>>> On Fri, Oct 23, 2015 at 10:17 AM, Moritz Lennert
>>> <mlennert at club.worldonline.be <mailto:mlennert at club.worldonline.be>>
wrote:
>>>
>>>     On 22/10/15 16:25, Johannes Radinger wrote:
>>>
>>>         Dear GRASS users,
>>>
>>>         Today I wanted to try the georectification tool g.gui.gcp in
>>>         GRASS 7 for
>>>         the first time. I was basically following the description on the
>>>         GRASS
>>>         wiki (https://grasswiki.osgeo.org/wiki/Georeferencing). In
>>>         particular, I
>>>         have a photograph from my camera with known reference points
which I
>>>         load into an unprojected XY location. My target location should
>>>         also be
>>>         a XY location as the picture is taken from a "virtual"
coordinate
>>>         system. Inside my target XY-location I try to open g.gui.gcp and
>>>         select
>>>         raster, and the location and mapset where my photograph is
>>>         stored. When
>>>         I want to click next I get following error/message: "You must
>>>         select a
>>>         valid location and mapset in order to continue" and I can't
>>>         proceed with
>>>         the rectification. Just this GUI message appears, no
>>>         error/warning in
>>>         the grass console etc. I am puzzled how to interpret that? What
>>>         is wrong
>>>         with the location/mapset? The mapset I've selected is existing
>>>         (I can
>>>         select it from the dropdown menu). I tried to select any other
>>>         location/mapset but receive always the same message.
>>>
>>>
>>>
>>>     Georectification is for georeferencing to a projected system. It
>>>     does not make sense to georeference to an XY-location.
>>>
>>>     I see two options for you:
>>>
>>>     - Import you image directely into the target region and use r.region
>>>     to adjust its boundary coordinates
>>>     - Define your own projection system to fit your needs.
>>>
>>>
>>> So far as I understand georectification and orthorectification in
>>> particular is to rectify a picture/photo/image based on spatially
>>> defined ground control points which might not be done by just adjusting
>>> the boundary coordinates. BTW I also tried the European LAEA coordinate
>>> system (EPSG 3035) as a target location which is not working either here
>>> in my machine/setup (same message as already mentioned). Here
>>> (
https://www.dropbox.com/s/snjzd8eu7b8115k/2015-10-22%2015.26.30.jpg?dl=0)
>>> you can find a a photo (*.jpg) which is an "areal" photo with known 3d
>>> coordinates for the single points (ground control points). I think this
>>> example clarifies and illustrates what I intend to do and why the target
>>> system can also be a XY location in my opinion. A rectification of this
>>> image should make the lines of the grid more or less parallel. Or do I
>>> get something completely wrong?
>>
>>
>> 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.
>>
>> Have you tried recreating the locations from scratch ?
>
>
> Your results look really reasonable.... that's what I was looking for...
>
> Actually, both XY locations are created from scratch (via the location
wizzard)
> I get following output for both XY locations:
>
> g.proj -p

> XY location (unprojected)
>
> 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...
>
> I just looked up the source code and the error message seems to be
related to follwoing line:
>
https://trac.osgeo.org/grass/browser/grass/branches/releasebranch_7_0/gui/wxpython/gcp/manager.py#L399
> 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....?
>
> Strange that orthorectification from one XY to antother XY location works
on other machines but not on mine.
>
> 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

I noticed you have strange version of wxpython. Any chance you could test
on machine with version 2.8.12.0 or a stable 3 version?

Anna
>
>>
>>
>> Moritz
>
>
>
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