[GRASSLIST:2296] Re: Import questions

Roderick A. Anderson raanders at tincan.org
Tue Aug 7 11:54:03 EDT 2001

On Tue, 7 Aug 2001, Rich Shepard wrote:

> > Second question, more on the capabilities of grass, as I am new to the
> > environment.  What type of resolution can you import without having it
> > take hours to process.  The Lidar data that I am working with is binned
> > at 5m, but it would be nice to have finer resolution for what I am
> > wantig to do.  I am not working with a great machine, a DELL Server with
> > a 500MhZ (?) single processor and 512MB RAM on RH7.1.  I am using the
> > precompiled libraries at this point in time.  Thanks for your help....
>   I'm working now with 10m DEMs and I have 15 adjacent quads patched
> together. My system is a PII/333 with 327M RAM and the processing speed is
> acceptable. I don't know where the speed bottleneck may be, but with a lot
> of data it may be disk access.

Probably. Do your systems use IDE or SCSI drives?  An IDE based system
has to use CPU resources to access the drives whereas a SCSI system uses
hardly any CPU.  Despite the 'proclaimed' speed of IDE drives they still
take system resources to read the data that could be better used to
process it.
   As the data grows your system may have to swap portions to disk.
Again this takes much more CPU resources on an IDE than a SCSI system.
Then read it back into memory.  And on and on and on.

                 Remove the word 'try' from your vocabulary ... 
                     Don't try.  Do it or don't do it ...
                                Steers try!

                                                            Don Aslett

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