[Mapserver-users] Large Raster files

[Martin Weinelt]

On Tuesday 18 May 2004 11:56, Paco Regodon wrote:
> On Monday 17 May 2004 16:52, Martin Weinelt wrote:
> > I also think that compressing the rasters is even contraproductive,
> > because 'in memory' there is no compression and you add an extra job
> > (decoding) to the application.
>
> If your hard disk is slow, or busy, it may be faster to read small jpeg
> images and decompress it on memory, than read big uncompressed bmps or
> tiffs.
>
> In our case, it is faster to use small 100KB jpegs, than big 1.5MB tiffs.
>
> You will need to test to find your optimal configuration.
>
> I agree with you that no reprojection should be done on-the-fly.

I always forgot hard disk access as a factor in raster processing time, but  - 
and Ed made the same point - it seems very much worth to consider.

BTW, with this thread I revisited Frank's 'raster-howto' in the documention 
section of the mapserver website. Most of what I mentioned has been 
documented there ('Raster Display Performance Tips') for a long time.  I 
guess that's were I started from ...

Martin