[Qgis-user] problems with georeferencing results

Tue Oct 25 15:46:13 PDT 2011

I have no good reason to say this other than a niggling suspicion[1] but, yes I think it can.

-ramon.
[1] We occasionally have problems with the georeferencer, where it tries to rotate an image that shouldn't need to be. It's rare enough that I haven't been able to track it down properly, but this is on my suspect list.

On 26/10/2011, at 06:18 , G. Allegri wrote:

> Sure Baren, this was just an exercise ;)
> I wanted to test regeoreferencing a raster and compare manual georeferencing against reprojection.
> I'm wondering if manually regeoreferencing an already georeferenced raster can break things...
> 
> Inviato da dispositivo mobile
> 
> Il giorno 25/ott/2011 22.43, "Barend Köbben" <kobben at itc.nl> ha scritto:
> Hi Giovanni,
> 
> I don't understand: you want to change a projected raster (in CRS 3003) to
> another projection (23023), so why do you need the georeferencing plugin?
> The data is already referenced, so it sounds to me you just want to
> re-project it, using the Raster > Warp menu.
> 
> Or am I missing something...?
> 
> Yours,
> 
> --
> Barend Köbben (Senior Lecturer)
> ITC - University of Twente, Faculty of Geo-Information
> Science and Earth Observation
> PO Box 217, 7500AE Enschede (The Netherlands)
> +31-(0)53 4874 253
> 
> 
> 
> On 25-10-11 21:23, "G. Allegri" <giohappy at gmail.com> wrote:
> 
> >Thanks for the reply.My raster infos are:
> >
> >PROJCS["Monte Mario / Italy zone 1",
> >    GEOGCS["Monte Mario",
> >        DATUM["Monte_Mario",
> >            SPHEROID["International 1924",6378388,297.0000000000014,
> >                AUTHORITY["EPSG","7022"]],
> >            AUTHORITY["EPSG","6265"]],
> >        PRIMEM["Greenwich",0],
> >        UNIT["degree",0.0174532925199433],
> >        AUTHORITY["EPSG","4265"]],
> >    PROJECTION["Transverse_Mercator"],
> >    PARAMETER["latitude_of_origin",0],
> >    PARAMETER["central_meridian",9],
> >    PARAMETER["scale_factor",0.9996],
> >    PARAMETER["false_easting",1500000],
> >    PARAMETER["false_northing",0],
> >    UNIT["metre",1,
> >        AUTHORITY["EPSG","9001"]],
> >    AUTHORITY["EPSG","3003"]]
> >Origin = (1554747.231034494200000,4924790.769999999600000)
> >Pixel Size = (100.000000000000000,-100.000000000000000)
> >Metadata:
> >  AREA_OR_POINT=Area
> >Image Structure Metadata:
> >  INTERLEAVE=BAND
> >Corner Coordinates:
> >Upper Left  ( 1554747.231, 4924790.770) (  9d41'17.95"E, 44d28'24.73"N)
> >Lower Left  ( 1554747.231, 4678290.770) (  9d39'49.22"E, 42d15'14.92"N)
> >Upper Right ( 1771747.231, 4924790.770) ( 12d24'49.32"E, 44d25'28.44"N)
> >Lower Right ( 1771747.231, 4678290.770) ( 12d17'30.22"E, 42d12'31.70"N)
> >Center      ( 1663247.231, 4801540.770) ( 11d 0'50.84"E, 43d20'53.55"N)
> >Band 1 Block=2170x1 Type=Float32, ColorInterp=Gray
> >  Min=-3.876 Max=2051.503
> >  Minimum=-3.876, Maximum=2051.503, Mean=152.789, StdDev=265.873
> >  NoData Value=0
> >  Metadata:
> >    STATISTICS_MINIMUM=-3.8761155605316
> >    STATISTICS_MAXIMUM=2051.5034179688
> >    STATISTICS_MEAN=152.78946158147
> >    STATISTICS_STDDEV=265.87340110007
> >
> >
> >As you can see the CRS is correctly defined, and the other metadata are
> >correct.
> >OTFR works fine, the raster is correctly reprojected on the 23032
> >reference.
> >No tfw or aux files in the same folder....
> >
> >It's making me crazy!
> >giovanni
> >
> >
> >2011/10/25 Richard Duivenvoorde <rdmailings at duif.net>
> >
> >On 2011-10-25 19:04, G. Allegri wrote:
> >> Here it is the GCP list picture: http://bit.ly/suh5UL
> >> (I wonder why ths srcY coordinates are shown as negative values)
> >
> >
> >What is projection of your raster, is it really epsg:3003 (to be tested
> >with 'gdalinfo yourraster'.)
> >
> >Is there maybe a tfw file hanging around which determines another extent
> >four your source raster? If seen this behaviour recently while using the
> >plugin.
> >
> >Try to set your tiff aside from other files, create a fresh epsg:23032
> >project with 'on the fly' and try again?
> >
> >Hope this helps.
> >
> >Regards,
> >
> >Richard Duivenvoorde
> >
> >
> >
> >
> >
> 
> 
> Faculty of Geo-Information Science and Earth Observation (ITC)
> University of Twente
> Chamber of Commerce: 501305360000
> 
> E-mail disclaimer
> The information in this e-mail, including any attachments, is intended for the addressee only. If you are not the intended recipient, you are hereby notified that any disclosure, copying, distribution or action in relation to the content of this information is strictly prohibited. If you have received this e-mail by mistake, please delete the message and any attachment and inform the sender by return e-mail. ITC accepts no liability for any error or omission in the message content or for damage of any kind that may arise as a result of e-mail transmission.
> _______________________________________________
> Qgis-user mailing list
> Qgis-user at lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/qgis-user