Ok, i got it. The reason it doesn't work is probably easily explained: the source X/Y are considered as raster space coordinates, while I thought that having the raster a CRS assigned this was kept into account during the warping. Probably manual re-georeferencing is conceptually unuseful, outside my exercise. Even if reprojection wasn't enough, the best way would be to remove any CRS reference from it. Tomorrow I will do more tests, but I'm pretty sure that I was simply trying a wrong procedure...
giovanni 2011/10/26 G. Allegri <gioha...@gmail.com> > 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" <kob...@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" <gioha...@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 <rdmaili...@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. >> >
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