[GRASS-dev] new addon: i.cutlines - Creates semantically meaningful tile borders

Moritz Lennert mlennert at club.worldonline.be
Thu Aug 16 03:26:09 PDT 2018

On 14/08/18 10:13, Moritz Lennert wrote:
> On 13/08/18 15:30, Markus Neteler wrote:
>> Hi Moritz,
>> On Mon, Aug 13, 2018 at 2:04 PM, Moritz Lennert
>> <mlennert at club.worldonline.be> wrote:
>>> On 13/08/18 13:41, Markus Neteler wrote:
>> ...
>>> AFAIK, the only moment where i.cutlines potentially reads the whole image
>>> would be in the edge detection part. That's why there is the tiling option
>>> to avoid just that.
>> I suppose you refer to
>> tile_width=integer
>>      Width of tiles for tiled edge detection (pixels)
>> tile_height=integer
>>      Height of tiles for tiled edge detection (pixels)
>> ?
>>> So, unless I'm forgetting something, you should be able
>>> to work on large images. If you have seen this crash the module, please file
>>> a bug report.

A colleague working with a large dataset > 10e9 pixels) just reported 
that the module does not crash, but that it seems to take "forever" (he 
stopped the process after a day). I guess this is in the r.cost phase.

An option would be to tile (and parallelize) the entire process which 
would mean finding cutlines in the individual tiles, making sure that 
the start and endpoints of these cutlines match the start and endpoints 
on the neighboring tiles...

Any suggestions are welcome.


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