Re: [gdal-dev] Fastest way to add the GeoTransform to a raster file with Python

Lucena, Ivan ivan.lucena at pmldnet.com
Thu Sep 18 12:42:53 EDT 2008


Frank,

>  -------Original Message-------
>  From: Frank Warmerdam <warmerdam at pobox.com>
>  Subject: Re: [gdal-dev] Fastest way to add the GeoTransform to a raster file	with Python
>  Sent: Sep 18 '08 16:09
>  
>  On 9/18/08, Matthieu Rigal <rigal at rapideye.de> wrote:
>  > Hi all,
>  >  Since the method of Create, SetGeoTransform, etc... is "complicated" and
>  >  unefficient from a performance point of view, what is the way to quickly add
>  >  the GeoTransform, taken from a referenced raster to a raster that have lost
>  >  the information.
>  
>  Matthieu,
>  
>  I assume the approach that is complicated is to create a
>  whole new image with Create(), setting the geotransform on
>  that and then copying over all the image data.  is that what
>  you mean?
>  
>  What format of imagery are you working with?  There are
>  different limitations on different drivers with regard to updating
>  georeferencing "in place".  For for some formats you can just
>  open a dataset in update mode, and call SetGeoTransform()
>  to update the georeferencing.  

Wouldn't be fair to say that some formats also requires a call to FlushCache() afterwards?

>  For other formats this is not
>  possible.
>  
>  Some formats support world files with various extensions.  For
>  these formats the easiest approach might be to just manually
>  write out a world file.
>  
>  >From the commandline the easiest way is to use gdal_translate
>  and the -a_ullr switch though internally this is of course creating
>  a new dataset and copying everything over.
>  
>  Best regards,
>  --
>  ---------------------------------------+--------------------------------------
>  I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
>  light and sound - activate the windows | http://pobox.com/~warmerdam
>  and watch the world go round - Rush    | Geospatial Programmer for Rent
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>  

Best regards,

Ivan



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