[Freegis-list] Creating JPEG images with gdal

[Tomas Zajc]

Correctme if I'm wrong. I can't use gdal to export an image I have on memory 
(ie. on an array). I want to open an existin file usin gda or reading a raw 
data (manualy) make some modifications (filtering, resampling, etc) and 
export as JPEG. Maybe I should just use the plain jpg library to dump my 
array on a file.

  Thanks, Tomas

On Tuesday 31 October 2006 16:34, Frank Warmerdam wrote:
> Tomas Zajc wrote:
> > Hi. I hope this is the right place to make this question. I'm taking my
> > first steps with the gdal library on C and almost my first steps in C
> > programming. I'm truing to creta some small jpg's using gdal.
> > I know there are two methods for generating images using gdal:
> > GDALCreateCopy and GDALCreate.
> >
> > I made a small program in which you can specify the driver at execution
> > time. When I use GTiff i get no problems. If I try to use JPEG I get:
> >
> > "ERROR 6: GDALDriver::Create() ... no create method implemented for this
> > format."
> >
> > I'm a bit lost, http://www.gdal.org/formats_list.html says JPEG can be
> > used for creation.
>
> Tomas,
>
> JPEG and most drivers for compressed formats in GDAL only support the
> CreateCopy() mechanism.  The formats list document means creation using
> one of Create() or CreateCopy(), and isn't meant to imply random writing
> is supported (as is the case with Create()).
>
> Best regards,