[Gdal-dev] Accessing Raster Attributes

Oliver Wesp wesp at gdv.com
Thu Mar 13 11:13:04 EST 2003


This one contains class_names:


It doesn't look that easy from my point of knowledge, so maybe you like to 
have a look at it.

Your help is greatly appreciated.

best regards

At 11:56 12.03.2003 -0500, you wrote:
>Oliver Wesp wrote:
>>Dear List,
>>what we like to do, is accessing the class_names attribute form ERDAS 
>>img-Files (hfa).  We thought  **GDALGetRasterCategoryNames( 
>>GDALRasterBandH hBand )  should to the trick, but it points to 
>>GetCategoryNames()  and this function returns null. Maybe we're on the 
>>wrong track anyway but this looks like it's not implemented.
>>We would not hesitate to develop this by ourselfs but maybe this has done 
>>before or someone can point us to the right direction.
>This hasn't been done yet, but would be a worthwhile improvement.  If you
>want to implement this, you would need to override the default implementation
>of the GetCategoryNames() method on the HFARasterBand class in gdal/frmts/hfa.
>You can use the low level HFA API to get the category names from the Erdas
>file though I don't know the structure off hand.   You can use the "hfatest"
>application in gdal/frmts/hfa to dump the file structure to try and pick out
>the location of the category names.
>If this gets to messy for you, email me a small .img file with category names
>and I will look into implementing it.
>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
>Gdal-dev mailing list
>Gdal-dev at remotesensing.org

Dipl.-Geogr. Oliver Wesp
Gesellschaft für geografische Datenverarbeitung
Binger Strasse 49-51
D-55218 Ingelheim
fon: +49 6132 714818
fax: +49 6132 714828
http: <http://www.gdv.com>www.gdv.com

More information about the Gdal-dev mailing list