[GRASS-dev] A few additional questions about i.segment

[Moritz Lennert]

As you might have gathered from my other messages on the list, we are 
currently running tests of i.segment in our department. A few questions 
came up (with my attempts at answers).


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> I had a look at the results, they are interesting. Maybe you could also try
> a combination of panchromatic, red and near-infrared bands and leave the
> other bands out. If it is possible to give different weights to the bands,
> then maybe 2 for the pan, 1 for red and 1 for NIR.

I think that is possible, but I have to check how. I imagine you would
work at the resolution of the pan for this...

>
> Regarding the size of the segments, we generally combine different
> segmentations, fine and coarse, depending on the type of objects that we
> have to classify. We also combine different segmentations because then we
> can use the classification of a fine segmentation as attribute for
> classifying a coarse segmentation (e.g. counting trees or houses in a large
> segment). Here we have very small segments and also very large ones together
> in the results, it is a bit different.

So to be able to do what you do now, you would need homogenous segment
sizes, i.e. not only a minsize (which I set fairly low in this first
trial: 2 pixels), but also the equivalent of a maxsize. Then, if you set 
the two fairly close to each other (i.e. minsize=900 and maxsize=1100 to 
get segments of +/- 1000 pixels).

I'll see how that can be achieved with the currently implemented module.
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Any hints on possible answers to these issues ?

Moritz