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

[Nikos Alexandris]

Below kept only timings and number of created segments (from previously posted 
tests as well as a few new ones), just as a reference.

All tests above threshold=0.95 fail to deliver. The extreme instruction 
threshold=0.95 derives 70 segments.  Above this, I think that everything would 
be merged in one segment, a result for which i.segment is not required anyway.

How this is related with the error message... ?

In any case, if wanted, I will try during the weekend to replicate a Huge 
region, as the one Moritz tested with a "rational" threshold (close to zero).

Thank you for this wonderful module!
Nikos


Nikos Alexandris wrote:
 
> # ###################################
> # A series of tests using default RAM
> 
> # threshold 0.1

> Segmentation converged after 11 iterations.
> Writing out segment IDs
> i.segment complete. Number of segments created: 25407
> 
> real    8m9.122s
> user    8m5.582s
> sys     0m0.296s

> # threshold 0.3

> Segmentation converged after 11 iterations.
> Writing out segment IDs
> i.segment complete. Number of segments created: 11684
> 
> real    12m20.273s
> user    12m19.466s
> sys     0m0.256s
> 
> # threshold 0.5
 
> Segmentation converged after 12 iterations.
> Writing out segment IDs
> i.segment complete. Number of segments created: 5495
> 
> real    17m35.330s
> user    17m34.302s
> sys     0m0.264s
> 
> # threshold 0.7

> Segmentation converged after 12 iterations.
> Writing out segment IDs
> i.segment complete. Number of segments created: 4911
> 
> real    18m15.143s
> user    18m11.188s
> sys     0m0.300s
> 
> # threshold 0.9
 
> Segmentation converged after 13 iterations.
> Writing out segment IDs
> i.segment complete. Number of segments created: 1276
> 
> real    30m30.619s
> user    30m29.010s
> sys     0m0.272s

# threshold 0.95
time i.segment group=pan out=pan_segmented_threshold_0.95_memory_30000 
threshold=0.95 memory=30000
..
Segmentation converged after 13 iterations.
Writing out segment IDs
i.segment complete. Number of segments created: 70

real    45m48.901s
user    45m45.064s
sys     0m0.512s

# threshold 0.955 (I guess identical to 0.95)
time i.segment group=pan out=pan_segmented_threshold_0.955_memory_30000 
threshold=0.955 memory=30000
..
Segmentation converged after 13 iterations.
Writing out segment IDs
i.segment complete. Number of segments created: 70

real    45m59.356s
user    45m55.280s
sys     0m0.584s

# threshold 0.96
time i.segment group=pan out=pan_segmented_threshold_0.96_memory_30000 
threshold=0.96 memory=30000
..
Pass 13:
ERROR: Invalid region id 0

real    48m0.629s
user    47m56.724s
sys     0m0.472s

# threshold 0.97
time i.segment group=pan out=pan_segmented_threshold_0.97_memory_30000 
threshold=0.97 memory=30000
..
Pass 11:
  40%   Pass 12:
Pass 13:
ERROR: Invalid region id 0

real    47m58.069s
user    47m53.976s
sys     0m0.628s

# threshold 0.99
time i.segment group=pan out=pan_segmented_threshold_0.99_memory_30000 
threshold=0.99 memory=30000

..
Pass 13:
ERROR: Invalid region id 0

real    37m24.352s
user    37m14.000s
sys     0m0.784s

time i.segment group=pan out=pan_segmented_threshold_0.99_memory_300 
threshold=0.99

..
Pass 13:
ERROR: Invalid region id 0

real    41m42.828s
user    41m39.932s
sys     0m0.680s