[GRASS-dev] i.segment: Invalid region id -1

Nikos Alexandris nik at nikosalexandris.net
Tue Dec 3 02:22:46 PST 2013

Nikos Alexandris wrote:

> >> I've tested this with at least three different similar cases. All work
> >> fine without the seed map! All fail with a seed map supplied. I guess,
> >> the only real difference is time for the processes to complete, right?

> > OK, I've just discovered that I mixed 8-bit (the Pan images) for the seed
> > map and 16-bit (the Multi-Spectral images).  So, seed -> 8-bit, group to
> > be segmented -> 16-bit. Does this play a role?

Markus Metz:

> No, the seed map must be integer (not more than 32 bit int), that's
> the only limitation. The data to be segmented can be anything, integer
> and/or floating point.

Good to know.

> But it does not make sense to use a pan band as seeds when segmenting
> the other bands. Seeds are typically the result of a previous run of
> i.segment or the result of a previous classification of the same data.

Then I have inserted a small mistake in my tests/workflow. Wanted to drive 
"finer objects" (from Pan) in bigger ones (based on MS). Will adjust.

Maybe we can add 1-2 sentences what a seed map is actually. What kind of 
numbers per object for example.

Thanks, N

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