[GRASS-user] Image segmentation

[Giuseppe Amatulli]

Thanks Pedro,
yes I had already tried, but i do not get really what I want. Moreover, the
delineation of watersheds is based on a predefined threshold that can be
quite arbitrary give really different results.

Best Giuseppe


On 18 January 2017 at 14:27, Pedro Venâncio <pedrongvenancio at gmail.com>
wrote:

> Hi Giuseppe,
>
> Maybe you can use r.watershed [0] to get the "basins".
>
> Best regards,
> Pedro Venâncio
>
> [0] https://grass.osgeo.org/grass72/manuals/r.watershed.html
>
> 2017-01-18 19:16 GMT+00:00 Giuseppe Amatulli <giuseppe.amatulli at gmail.com>
> :
>
>> Hi all,
>>
>>
>>
>> I would like to "segment" an image using a sort of Voronoi
>> <https://urldefense.proofpoint.com/v2/url?u=https-3A__en.wikipedia.org_wiki_Voronoi-5Fdiagram&d=CwMFaQ&c=-dg2m7zWuuDZ0MUcV7Sdqw&r=WXcS58IfKIlNshJRe1p51UO4aV2lTPDP2KeAvExEWkM&m=-q05ggwZ7xB31XO6ZJhmFYht4GKQ2nmFojS6li_t2As&s=Cqh6IsnZ5-oxcE2yVMRceyhb4KwTB2q3ihdDv8E4GWg&e=> algorithm
>> on a cost surface instead of distance between point.
>>
>>
>>
>> Below you can see an image where the black pixels identity areas with
>> high cost value. I would like to identify the "valley" between theses black
>> areas.
>>
>>
>>
>> In the second image I draft by hand an ideal solution for few high cost
>> areas.
>>
>>
>>
>> Which grass command can do this kind of delineation?
>>
>>
>>
>> Thanks,
>>
>>
>> Giuseppe
>>
>>
>> [image: Inline images 1]
>>
>> [image: Inline images 2]
>>
>> --
>> Giuseppe Amatulli, Ph.D.
>>
>> Research scientist at
>> Yale School of Forestry & Environmental Studies
>> Yale Center for Research Computing
>> Center for Science and Social Science Information
>> New Haven, 06511
>> Teaching: http://spatial-ecology.org
>> <https://urldefense.proofpoint.com/v2/url?u=http-3A__spatial-2Decology.org&d=CwMFaQ&c=-dg2m7zWuuDZ0MUcV7Sdqw&r=WXcS58IfKIlNshJRe1p51UO4aV2lTPDP2KeAvExEWkM&m=-q05ggwZ7xB31XO6ZJhmFYht4GKQ2nmFojS6li_t2As&s=2WUybjpe6r7Te9PU70VIWSGVIuSPRvgtrQM-Ej6RBuY&e=>
>> Work:  https://environment.yale.edu/profile/giuseppe-amatulli/
>>
>>
>>
>>
>> _______________________________________________
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>> grass-user at lists.osgeo.org
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>>
>
>


-- 
Giuseppe Amatulli, Ph.D.

Research scientist at
Yale School of Forestry & Environmental Studies
Yale Center for Research Computing
Center for Science and Social Science Information
New Haven, 06511
Teaching: http://spatial-ecology.org
Work:  https://environment.yale.edu/profile/giuseppe-amatulli/
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