[gdal-dev] GDAL 1.8.0 and MrSid "no-data" values

[Oyvind Idland]

Ok, thanks.


-- Oyvind

On Fri, May 27, 2011 at 9:10 PM, Kirk McKelvey <kmckelvey at lizardtech.com>wrote:

> Sorry Oyvind, somehow I missed your note about it being MG2.
>
>
>
> I looked into this yesterday and it is indeed a difference in the v8 DSDK.
> Image properties that are available through the API (such as the nodata
> value, dynamic range, etc.) are no longer being inserted into the metadata.
> This means they do not get transcribed into the GDAL metadata during
> initialization of the MrSIDDataset either.
>
>
>
> Meanwhile, it looks like MrSIDRasterBand::GetNoDataValue() was disconnected
> due to a difference in the way LizardTech and GDAL interpret NODATA
> (per-band vs. all-bands), so there is no longer a way to get at this info at
> all.
>
>
>
> For the moment the only suggestion I have is to reactivate the code in
> MrSIDRasterBand::MrSIDRasterBand() (approx. line 366ff in mrsiddataset.cpp)
> that sets the nodata value for the raster band.  You will of course have to
> deal with the different nodata semantics between LT and GDAL.
>
>
>
> I will work on a patch to reinsert the NO_DATA_VALUE into the metadata.
>
>
>
> Kirk.
>
>
>
> *From:* gdal-dev-bounces at lists.osgeo.org [mailto:
> gdal-dev-bounces at lists.osgeo.org] *On Behalf Of *Oyvind Idland
> *Sent:* jeudi 26 mai 2011 01:16
>
> *To:* gdal-dev at lists.osgeo.org
> *Subject:* Re: [gdal-dev] GDAL 1.8.0 and MrSid "no-data" values
>
>
>
> Hi,
>
> should I assume that this error is due to the DSDK 8.x version ?
>
> -- Oyvind
>
> On Mon, May 16, 2011 at 8:30 AM, Oyvind Idland <oyvind.idland at gmail.com>
> wrote:
>
> Hi,
>
> The file I'm using is actually MG2, using only 3 bands.
>
> Note, thats its the same file I used for testing in 1.7.x aswell.
>
>
> - Oyvind
>
>
>
> On Fri, May 13, 2011 at 4:08 PM, Kirk McKelvey <kmckelvey at lizardtech.com>
> wrote:
>
> Is this with MG3 or MG4 files?  MG4 uses an alpha channel instead of
> nodata, so what you describe would be expected in that case.
>
>
>
> *From:* gdal-dev-bounces at lists.osgeo.org [mailto:
> gdal-dev-bounces at lists.osgeo.org] *On Behalf Of *Oyvind Idland
> *Sent:* vendredi 13 mai 2011 04:28
> *To:* gdal-dev at lists.osgeo.org
> *Subject:* [gdal-dev] GDAL 1.8.0 and MrSid "no-data" values
>
>
>
> Hi,
>
> I just updated to 1.8.0 from 1.7, using the MrSid DSDK 8.0.
>
> In order to handle transparency, i have until now used the metadata values
> from "IMAGE__NO_DATA_VALUE",
> and simply masked away pixels.
>
> After upgrading, the IMAGE__NO_DATA_VALUE yields nothing, neither is it
> listed when using gdalinfo.
>
> The band->GetNoDataValue() doesn't give me any hints either.
>
> Should I handle this in a different way ?
>
>
> -- Oyvind
>
>
>
>
>
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