[Gdal-dev] Enabling PAM By Default

[Howard Butler]

Frank,

In my opinion, there is little downside to enabling this by default  
in trunk right now.  I'll think of it as doing my own little part to  
make ESRI's software that much better :P

Seriously, I think this is a good idea, and maybe it will get folks  
thinking about incorporating PAM output in other contexts if they  
know it will be generally available.

Howard

On Sep 19, 2007, at 9:51 PM, Frank Warmerdam wrote:

> Folks,
>
> A mechanism called PAM (Persistent Auxilary Metadata) was  
> engineered into
> GDAL around the 1.3.0 timeframe I think.  This is essentially a  
> mechanism
> to store georeferencing, metadata, statistics and other auxilary data
> in an XML file associated with a dataset for formats that don't  
> support
> the information internally.  The XML file has the extension .aux.xml.
>
> Currently this mechanism is only enabled if the GDAL_PAM_ENABLED
> configuration option (ie. env. variable) is YES.  Thus, by default we
> have not been using it most of the time.  It is enabled by default in
> ArcGIS and I sometimes run with it enabled.
>
> I would like to move to having PAM turned on by default during our
> development cycle and to have a build option indicating whether it is
> enabled or disabled.  Shortly before 1.5 release we should be able to
> make a final decision on whether we want it enabled in the 1.5.0
> release depending on whether we find it is causing many problems.
>
> My longer term goal is to have it on all the time except when  
> explicitly
> turned off - that is to have it as a default behavior.  Mainly I  
> want this
> because it is hard to be sure it is working properly when it is rarely
> used except in the ArcGIS environment.  But I also think it is a  
> valuable
> facility and could be a benefit to most GDAL users if more was  
> known about
> it, and it was generally available.
>
> Does anyone have an objection to my turning it on now, and us having a
> formal motion on whether it should be enabled shortly before the 1.5
> release?  Some rather brief information on PAM is available at:
>
>   http://www.gdal.org/classGDALPamDataset.html
>
> BTW, I have confirmed that the autotest suite runs clean (at least  
> on linux)
> with PAM enabled.
>
> 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    | President OSGeo, http:// 
> osgeo.org
>
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