[GRASS-dev] RE: [GRASS-user] problems with r.cost

[Jerry Nelson]

The large file support option doesn't help with all grass routines
unfortunately. 

The following has to be in the Make file for the specific module

ifneq ($(USE_LARGEFILES),)
        EXTRA_CFLAGS = -D_FILE_OFFSET_BITS=64
Endif

It is not in the r.cost Make file, which means I think (remember I'm not a C
programmer) that compiling with large file support won't help.

The nice thing, in principle, about the r.terracost extension is that it can
handle REAAALLY big surfaces. It does some kind of breaking the surface up
into smaller pieces, doing the cost calcs and then patches them back
together, somehow dealing with the issue of going across different pieces.
And also in principle it can be run on a cluster. I keep repeating 'in
principle' because I have never actually done this myself. 

Regards, Jerry 

-----Original Message-----
From: Paul Haverkamp [mailto:pjhav at ucdavis.edu] 
Sent: Wednesday, May 23, 2007 1:51 PM
To: Jerry Nelson; 'Hamish'
Cc: grassuser at grass.itc.it
Subject: RE: [GRASS-user] problems with r.cost


Thanks Jerry,

I'll look into this.  I realized that I'm running on a 64 bit machine, so
the memory really shouldn't be an issue.  So I'll check out the recompile.

thanks,

paul


> One thing to try if you haven't already is to recompile grass with large
> file support included. I don't know why that's not done automatically but
> apparently it isn't.
> 
> Another, if region size is really the issue and you are a C programmer or
> know one, is to modify the make file of a grass add-on called
> r.terracost.
> It was written as a CS project at Bowdoin at a time when grass was at
> version 5.3. With the move to version 6, the make process changed
> slightly.
> The r.terracost files are available at
> http://www.bowdoin.edu/~ltoma/research.html
> 
> Or you could get grass5.3 and run r.terracost with it.
> 
> Regards, Jerry
> 
> -----Original Message-----
> From: grassuser-bounces at grass.itc.it
> [mailto:grassuser-bounces at grass.itc.it]
> On Behalf Of Paul Haverkamp
> Sent: Wednesday, May 23, 2007 12:45 PM
> To: Hamish
> Cc: grassuser at grass.itc.it
> Subject: Re: [GRASS-user] problems with r.cost
> 
> 
> Hi Hamish,
> 
> Thanks for getting back to me.
> 
> I am using 6.2.1, and g.region -p gives the info:
> 
> projection: 1 (UTM)
> zone:       10
> datum:      nad83
> ellipsoid:  grs80
> north:      4269999
> south:      4180119
> west:       598614
> east:       651978
> nsres:      3
> ewres:      3
> rows:       29960
> cols:       17788
> cells:      532928480
> 
> I'm trying to run with the resolution of 3m, but when I change it to 30m,
> there isn't a problem.  Using much smaller regions doesn't seem to have
> this problem.  So is the file just too large at too small of a
> resolution?
>  I'll try to run Spearfish and let you know.
> 
> thanks again,
> 
> paul
> 
> 
> > Paul Haverkamp wrote:
> > > 
> > > i'm a very new user to grass and am using r.cost in grass6.2.  i'm
> > > trying to run a cost analysis on my raster and having some
> difficulty.
> > 
> > which version of 6.2? 6.2.0 or 6.2.1?
> > 
> > how big is your region? (g.region -p) Does it happen if you make the
> > region smaller or adjust the resolution?
> > 
> > can you reproduce it using the Spearfish demo dataset? if so, can you
> > post instructions with that in the grass bug tracker?
> > 
> > 
> > thanks,
> > Hamish
> > 
> 
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