mapserver raster documentation

[Frank Warmerdam]

John Mitchell wrote:
> Hi,
> 
> I have been reading over the mapserver raster documentation and I have a 
> few questions:
> 
> 1.) It mentioned a 4 gb limit for GeoTiff files.  Is this for GeoTiff 
> files or that GeoTiff's can only be tiled up to 4 gb.  Is this 4 gb 
> limit an issue with mapserver or GeoTiff.

John,

The 4GB limit is inherent in TIFF, and it isn't specific to mapserver
in any way.  Note that you can setup a tile index with my TIFF files
smaller than 4GB.  There is no meaningful limit on the amount of data
that can be in a tileindex.

> 2.) Assuming the 4 gb GeoTiff limit then the GeoTiff would need to be 
> converted to Erdas Imagine (HFA) format.  The Documentation said that 
> the Imagine format is already Tiled.  Correct?    

Imagine format is inherently tiled, normally with 64x64 blocks.

> 3.) Is the format the same to access an Imagine file as it is to access 
> a GeoTiff?  I have a sample .map segment that I use to access a GeoTiff:

Yes, Imagine files are accessed the same way in mapserver as GeoTIFF files
are.

>  OUTPUTFORMAT
>   NAME png
>   DRIVER "GD/PNG"
>   MIMETYPE "image/png"
>   IMAGEMODE RGB
>   EXTENSION "png"
>  END

I'm not sure why this OUTPUTFORMAT declaration is in your email.  It didn't
seem to relate to the text of question 3.  But I will say that output formats
is to some degree a distinct issue from input raster formats.

Best regards,
-- 
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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