[GRASS-dev] i.segment: invalid region id 0

[Nikos Alexandris]

On Tuesday 16 of July 2013 00:09:44 Nikos Alexandris wrote:
> Moritz Lennert wrote:
> 
> [..]
> 
> >  > time i.segment -w group=pan_r_ir out=seg_weighted_pan_r_ir
> > 
> > threshold=0.01 memory=8192
> > Loading input bands...
> > Pass 1:
> > ERROR: Invalid region id 0
> 
> [..]
> 
> > What could be the problem ?
> 
> Moritz, Markus,
> 
> the same error today while performing a "random" test. Disk capacity and RAM
> plenty here.
> 
> time i.segment group=pan out=pan_segmented_plantations_area_threshold_1
> threshold=0.99
> 
> Loading input band...
> Pass 1:
> Pass 2:
> Pass 3:
> Pass 4:
> Pass 5:
> Pass 6:
> Pass 7:
> Pass 8:
> Pass 9:
> Pass 10:
> Pass 11:
> Pass 12:
> Pass 13:
> ERROR: Invalid region id 0
> 
> real    40m44.339s
> user    37m34.357s
> sys     0m0.380s
> 
> Details
> 
> projection: 1 (UTM)
> zone:       38
> datum:      wgs84
> ellipsoid:  wgs84
> north:      -2571782.5
> south:      -2574924.5
> west:       359153.5
> east:       359525
> nsres:      0.5
> ewres:      0.5
> rows:       6284
> cols:       743
> cells:      4669012
> 
> Let me know how I can help.

The "same" process, that is i.segment on a single Panchromatic band 
(WorldView-1), in a region composed by 4669012 cells, however, with a 
threshold of "=0.5", took 20 minutes to complete successfully.

# exact instruction -- includes memory=13000
i.segment group=pan out=pan_segmented_plantations_region threshold=0.5 
memory=13000

What is positive (maybe too much!) is that i.segment respects memory and CPU 
resources.  Keeping an eye on the process running via KDE's System Activity 
app, the process kept only one core busy at 100% and occupied no more than 
120MB of memory! (?)

I will repeat the above "failed" process with memory=Something and report 
back.

Nikos
Nikos