[gdal-dev] cutting up large TIFF files with gdal_translate

[Frank Warmerdam]

On Wed, Aug 22, 2012 at 9:38 AM, Zoltan Szecsei <zoltans at geograph.co.za> wrote:
> Hi,
> I have a large image bounded by:
>
> Upper Left  (  447007.599, 7132849.501) ( 32d28'15.03"E, 25d55'19.12"S)
> Lower Left  (  447007.599, 7127851.511) ( 32d28'14.30"E, 25d58' 1.59"S)
> Upper Right (  451005.901, 7132849.501) ( 32d30'38.75"E, 25d55'19.63"S)
> Lower Right (  451005.901, 7127851.511) ( 32d30'38.08"E, 25d58' 2.10"S)
>
> and I would like to cut it up into 1Km squares starting on the 447000
> 7133000 boundary.
> The problem is that using:
> gdal_translate -of JPEG -projwin $tlx $tly $brx $bry  m_36s.tif
> m_36s_${r}${c}.jpg
>
> gives me:
> Computed -srcwin -152 97030 20008 20008 from projected window.
> Computed -srcwin falls outside raster size of 79999x100001.
>
> Whilst the error is understandible, I was hoping that extra pixels would be
> automatically inserted as no_data values to make up my 1km tiles.

Zoltan,

Unfortunately gdal_translate does not support this.  Instead I'd
suggest using gdalwarp:

  gdalwarp -te xmin ymin xmax ymax srcfile dstfile

The "target extent" window may be off the source image without
problem.

> I'm not sure if -outsize will help me or not.
> (ie: I first increase the area of my original tiff image so that it is
> larger than my required tiles, and then cut it up as above)

The -outsize makes the output larger (or smaller) by replication
or decimation not by growing the extents.

Best regards,
Frank

> Is this the function of -outsize ?
>
> Any suggestions how I should go about this issue?
>
> Thanks & regards,
> Zoltan
>
>
>
> --
>
> ===========================================
> Zoltan Szecsei PrGISc [PGP0031]
> Geograph (Pty) Ltd.
> P.O. Box 7, Muizenberg 7950, South Africa.
>
> 65 Main Road, Muizenberg 7945
> Western Cape, South Africa.
>
> 34° 6'16.35"S 18°28'5.62"E
>
> Tel: +27-21-7884897  Mobile: +27-83-6004028
> Fax: +27-86-6115323     www.geograph.co.za
> ===========================================
>
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