[Qgis-user] Problem with adding GeoTIFF raster

[Micha Silver]

Kieron Dunbar wrote:

> I tried to import one of the GeoTIFF rasters from 
> www.ordnancesurvey.gov.uk into QGis, but it seems to ignore the 
> co-ordinates reported by gdalinfo, as it puts the top left corner at 
> 0,0 with a scale of 1 pixel per unit. Is there a way I can put this 
> file in the correct position? I haven't used QGis or GDAL before, so I 
> apologise if I have missed something obvious?
>
> The properties gdalinfo reports are as follows (slightly abbreviated):
>
> Driver: GTiff/GeoTIFF
> Files: 1 250 000 Scale Raster/data/HP.tif
> Size is 4000, 4000
> Coordinate System is `'
Here's the problem  ^^^^

After unzipping the downloaded file, if you look in the directory "data" 
there's another directory "georeferencing files". There you'll find the 
*.tfw (world files) for each of the the *tif files. It's strange that 
they are delivered in a separate directory. Just copy all the *.tfw 
files into the same dir as the *.tif files, and they'll be positioned 
correctly.

One additional note: When you load the layers into QGIS, be sure to 
choose the "National Grid" as the CRS. That's EPSG:27700.

> Metadata:
>   TIFFTAG_IMAGEDESCRIPTION=1:250 000 TILE HP.TIF
>   TIFFTAG_DATETIME=2009:05:01 08:32:51
>   TIFFTAG_COPYRIGHT=ORDNANCE SURVEY CROWN COPYRIGHT 2009
>   TIFFTAG_XRESOLUTION=254
>   TIFFTAG_YRESOLUTION=254
>   TIFFTAG_RESOLUTIONUNIT=2 (pixels/inch)
> Image Structure Metadata:
>   COMPRESSION=LZW
>   INTERLEAVE=BAND
> Corner Coordinates:
> Upper Left  (    0.0,    0.0)
> Lower Left  (    0.0, 4000.0)
> Upper Right ( 4000.0,    0.0)
> Lower Right ( 4000.0, 4000.0)
> Center      ( 2000.0, 2000.0)
> Band 1 Block=4000x65 Type=Byte, ColorInterp=Palette
>   Color Table (RGB with 256 entries)
>     0: 59,43,48,255
> ...
>   255: 253,252,252,255
>
> Many thanks.
> Kieron Dunbar
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-- 
Micha Silver
Arava Development Co. +972-52-3665918
http://www.surfaces.co.il