On Fri, Oct 23, 2015 at 11:19 AM, Moritz Lennert < mlenn...@club.worldonline.be> wrote:
> On 23/10/15 10:56, Johannes Radinger wrote: > >> >> >> On Fri, Oct 23, 2015 at 10:17 AM, Moritz Lennert >> <mlenn...@club.worldonline.be <mailto:mlenn...@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. > > Moritz >
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