[Gdal-dev] Accessing Raster Attributes

[Oliver Wesp]

Frank,

This one contains class_names:

http://gdal.velocet.ca/projects/imagine/data/4bit.img

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
Oliver

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.
>
>Oliver,
>
>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
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Dipl.-Geogr. Oliver Wesp
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