[Gdal-dev] Enhancement to access Arc/Info Binrary Grid in zip file

[Frank Warmerdam]

Kevin Ruland wrote:

> I've been lurking for a little while and am a relatively new user of 
> the GDAL library.  Please excuse any "neubies" I might make.
>
> I'm in the process of cataloging all of our raster datasets and am 
> troubled by the Arc/Info multiple file setup.  Keeping track of 
> multiple files is significantly harder than tracking them all in, say, 
> a zip file.  I was wondering if anyone has considered storing these 
> multi-resource formats in a container of some kind, what the 
> implications are, and if it would even be worthwile to persue.


Kevin,

I don't think it would be particularly easy to implement this though it 
is in theory doable, at
least for one format at a time.

One problem is that formats like Arc/Info binary coverages are random 
access, and in a zip
file each file is compressed as one big stream.  That means if you want 
data from the middle
of the file, you need to uncompress all the preceeding data (and discard 
it) to get the data
you want.  In some cases this could completely hammer performance.

While I sympathaize with your concern about managability of directory 
trees, I am doubtful
it is practical from a work or a performance point of view to change 
most of the multi-file
formats to support zipped version.

Best regards.

-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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