i.segment.hierarchical: why is there a mandatory output option

[mlennert]

i.segment.hierarchical has the following parameters (among others):

          output   Name of output segment raster map
  outputs_prefix   Name for output raster maps from segment
                   par défaut: seg__%.2f

I don't really understand the sens of 'output': The whole idea of the module is to create multiple output maps containing the results of hierarchical segmentation. So why would one need one single output map name ?

[zarch]

Replying to mlennert:

i.segment.hierarchical has the following parameters (among others):

          output   Name of output segment raster map
  outputs_prefix   Name for output raster maps from segment
                   par défaut: seg__%.2f

I don't really understand the sens of 'output': The whole idea of the module is to create multiple output maps containing the results of hierarchical segmentation. So why would one need one single output map name ?

Actually I wrote this module to have a single segmented output map! :-)

The idea of the module was to parallelize the i.segment module into cores and nodes in a cluster on single tiles, once the segmentation per tile is done then patch the tiles in a unique map and apply i.segment using the segmented map as seed to obtain as output a large segmented map.

I put also the option outputs_prefix, that probably should be change in "basename" to define the name of the "temporary" segmented tiles.

[mlennert]

Replying to zarch:

Replying to mlennert:

i.segment.hierarchical has the following parameters (among others):

          output   Name of output segment raster map
  outputs_prefix   Name for output raster maps from segment
                   par défaut: seg__%.2f

I don't really understand the sens of 'output': The whole idea of the module is to create multiple output maps containing the results of hierarchical segmentation. So why would one need one single output map name ?

Actually I wrote this module to have a single segmented output map! :-)

Oh, I guess I was fooled by the name. 'hierarchical' evokes several maps for me...

The idea of the module was to parallelize the i.segment module into cores and nodes in a cluster on single tiles, once the segmentation per tile is done then patch the tiles in a unique map and apply i.segment using the segmented map as seed to obtain as output a large segmented map.

Well, it is also very nice to create a series of hierarchically segmented maps, even without using the parallel processing mode (which actually fails for me - see #2902).

I put also the option outputs_prefix, that probably should be change in "basename" to define the name of the "temporary" segmented tiles.

But if you only create one output map, why go through a whole list of thresholds for segmentation ?

In my use case, 'output' is not necessary, 'basename' is. So, at least they should each be optional. BTW, concering this basename, see also #2914. And while you're at it, could you also give your opinion on #2915 ?

[zarch]

Replying to mlennert:

Replying to zarch:

Replying to mlennert: I put also the option outputs_prefix, that probably should be change in "basename" to define the name of the "temporary" segmented tiles.

But if you only create one output map, why go through a whole list of thresholds for segmentation ?

I've used to identify the "best" segment threshold

In my use case, 'output' is not necessary, 'basename' is. So, at least they should each be optional.

Yes, indeed they should be both optionals.

BTW, concering this basename, see also #2914. And while you're at it, could you also give your opinion on #2915 ?

Actually I did this morning but I realize that my replies were losts, let's do it again.

[martinl]

Still relevant?

[martinl]

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