[GRASS-user] <i.landsat.trim> -- script to trim Landsat images, make footprints and all-coverage mask

Nikos Alexandris nik at nikosalexandris.net
Thu Dec 20 13:03:32 PST 2012

Alexander Muriy wrote:

> ...shell script <i.landsat.trim>, that trims the "fringe" from the
> borders of Landsat images, for each band separately or with the MASK where
> coverage exists for all bands.
> Usage:
>  i.landsat.trim [-maf] [input=string] [input_base=string]
>    [input_prefix=string] output_prefix=string [rast_buffer=value]
>    [gener_thresh=value] [--verbose] [--quiet]
> Parameters:
>     rast_buffer   Distance for raster buffering (in meters)
>                   default: 300

Hello Alex!

I am testing <i.landsat.trim>.  Nice work!  I do have a question though:

how do we interpret exactly the  "rast_buffer"  parameter?

Testing on a single L5T band, I get strange (to me) results with various buffer 
distances (e.g., 100, 150, 200, 5000, 10000).  Where does the  buffer  start? 
Does it start from the outer non-NULL pixels of the image for example?  Is it 
expected that some distance (e.g. 100) will result in an (almost) empty image?

Any help appreciated in gaining complete control over the module's 

Best regards, Nikos

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