ArcInfo GRID performance vs TIFF files

[Frank Warmerdam]

On 4/18/05, Nuno Gil <nunoragil at gmail.com> wrote:
> Dear listers,
> I would like to ask if using GRID files or TIFF files as an input in
> MapServer is the same in what concerns performance?
> I have typically tiles of 5ºx5º degrees with 1 arcsec resolution
> (approx 900 MB)... If I request a smaller part of that tile I suppose
> MapServer does not need to read the entire tile, am I correct?

Nuno, 

The Arc/Info binary grid form is internally tiled in 256x4 bricks, so
access from MapServer (via GDAL) to binary grids will generally not
have to read much extra data.  

This does not apply to ascii grids which are of course dead slow to 
use at any reasonable size. 

Best regards,
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