[GRASS-user] i.segment and i.segment.stats errors

[Moritz Lennert]

On 09/10/18 13:48, Jamille Haarloo wrote:
> Hello Moritz,
> 
> First a pop-up came about not finding it, so reinstalled it.
> 
> g.extension r.object.geometry
> WARNING: Extension <r.object.geometry> already installed. Re-installing...
> Downloading precompiled GRASS Addons <r.object.geometry>...
> Updating addons metadata file...
> Installation of <r.object.geometry> successfully finished
> (Mon Oct 08 16:55:04 2018) Command finished (4 sec)
> (Mon Oct 08 16:55:53 2018)
> r.object.geometry SegmW24IDM4DV4 output=test.csv
> Calculating statistics
> Writing output
> (Mon Oct 08 16:56:14 2018) Command finished (21 sec)

Could you provide the first lines of content of test.csv ?

> 
> g.region -p
> projection: 1 (UTM)
> zone:       21
> datum:      wgs84
> ellipsoid:  wgs84
> north:      634826.41313284
> south:      611477.61329757
> west:       775494.11663193
> east:       793630.22784822
> nsres:      0.50000642
> ewres:      0.50000307
> rows:       46697
> cols:       36272
> cells:      1693793584


So you have over 1.5 billion cells. That's quite big, but not impossible 
to handle. Depends on your machine.

> 
> r.info <http://r.info> SegmW24IDM4DV4
>   +----------------------------------------------------------------------------+
>   | Map:      SegmW24IDM4DV4                 Date: Fri Oct 05 23:46:04 
> 2018    |
>   | Mapset:   LUP1                           Login of Creator: haarlooj  
>        |
>   | Location: Cottica_LUP                                                
>        |
>   | DataBase: Z:\GRASS_GIS                                              
>         |
>   | Title:                                                              
>         |
>   | Timestamp: none                                                      
>        |
>   |----------------------------------------------------------------------------|
>   |                                                                      
>        |
>   |   Type of Map:  raster               Number of Categories: 0        
>         |
>   |   Data Type:    CELL                                                
>         |
>   |   Rows:         46697                                                
>        |
>   |   Columns:      36272                                                
>        |
>   |   Total Cells:  ju   


This 'ju' is weird, here.


>         |
>   |        Projection: UTM (zone 21)                                    
>         |
>   |            N: 634826.41313284    S: 611477.61329757   Res: 
> 0.50000642      |
>   |            E: 793630.22784822    W: 775494.11663193   Res: 
> 0.50000307      |
>   |   Range of data:    min = 1  max = 12901                            
>         |
>   |                                                                      
>        |
>   |   Data Description:                                                  
>        |
>   |    generated by i.segment                                            
>        |
>   |                                                                      
>        |
>   |   Comments:                                                          
>        |
>   |    i.segment --overwrite group="DV4 at LUP1,IDM4 at LUP1,W2 at LUP1,W4 at LUP1" 
> out\   |
>   |    put="SegmW24IDM4DV4" threshold=0.25 radius=1.5 
> method="region_growin\   |
>   |    g" similarity="euclidean" minsize=5000 memory=10000 
> seeds="SegW24IDM\   |
>   |    4DV4 at LUP1" goodness="SegmW24IDM4DV4_goodn"


You only have 12901 segments, so an average size of 32822m2 per segment. 
Is this what you aimed for ? As you asked for a minsize of 5000 pixels I 
guess this is deliberate.

You threshold of 0.25 is also very high...

Moritz