[GRASS-user] Question to the input seed grid of i.segment

[Raphael Knevels]

Dear GRASS-community,

 

I have to perform a multi-scale, object-oriented analysis on an image with
about 93'535'000 pixels^^ 

 

I'm doing the process on a server, so I need for one simple segmentation
process approximately 700-800 minutes depending on the threshold. The same
process in SAGA takes around 60 minutes with the use of seed points (as grid
pixels). But in SAGA there is no possibility for hierarchical segmentation.
Therefore, I would like to use the seed points of SAGA as Input for GRASS
7.2.0 to speed up i.segment.

 

However, I am not capable to transform the seeds of SAGA to a meaningful
i.segment input. How has to look an optimal input seeds grid for GRASS?

 

- I've already found out is that it must be an integer grid with positive
seed numbers. The float-grid output of SAGA seed contains single pixels
surrounded by no-data values. When I transform the SAGA seed to an integer
grid and into GRASS (by (r)gdal), I have to give no data values a positive
number. Negative values in the seed-grid-input lead to an error in
i.segment.

 

I would be glad for any hint and reply.

 

Best regards

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