[GRASS-user] Is Watershed image segmentation program in GRASS GIS?

[Uttam Kumar]

Hi Leonardo,

I went through the paper "
Semi-automated_mapping_of_burned_areas_in_semi-arid_ecosystems_using_MODIS_time-series_imagery
<https://www.researchgate.net/publication/269692754_Semi-automated_mapping_of_burned_areas_in_semi-arid_ecosystems_using_MODIS_time-series_imagery>"
and I am also trying to do something similar except that I want to separate
water bodies.

Is it possible for you to share the GRASS code on segmentation (based on
Pratt,  W.K.,  2001.  Digital  Image  Processing.  NY:
Wiley-Interscience,  New  York,  pp. 491–556.) which you executed as an ad
hoc function in r.mapcalc.

Appreciate any help.

Uttam.

On Wed, Nov 11, 2015 at 8:48 AM, Leonardo Hardtke <leohardtke at gmail.com>
wrote:

> Hi there...
>
> I used r.grow to segment dNBR images to map wildfires. See:
>
>
> https://www.researchgate.net/publication/269692754_Semi-automated_mapping_of_burned_areas_in_semi-arid_ecosystems_using_MODIS_time-series_imagery
>
> Hope it helps...
>
>
> 2015-11-11 3:47 GMT-03:00 Uttam Kumar <uttamsinha09 at gmail.com>:
>
>>
>>
>> Hi All,
>>
>> Is watershed image segmentation program or a similar module available in
>> GRASS GIS?
>>
>> I understand that we have r.watershed, i.segment and r.grow in GRASS GIS.
>> But I do not know which one best suits my problem.
>>
>> The problem is:
>>
>> I have two layers of raster data -
>> 1.) a gradient image (obtained by applying a 3 x 3 sobel filter on a
>> water index using r.mapcalc), and
>> 2.) a seed image of 2 classes labelled as "1" and "2" and remaining
>> pixels as "0".
>>
>> I want to use the seed image and the gradient image (which shows
>> direction of change in intensity) information to perform segmentation using
>> the watershed algorithm and label all "0" pixels as either 1 or 2.
>>
>> r.watershed does not use watershed segmentation algorithm. i.segment is
>> something close but I am not sure.
>>
>> Please suggest.
>>
>> Any comment is appreciated.
>>
>> Uttam.
>>
>>
>>
>> _______________________________________________
>> grass-user mailing list
>> grass-user at lists.osgeo.org
>> http://lists.osgeo.org/mailman/listinfo/grass-user
>>
>
>
>
> --
> Dr. Leonardo A. Hardtke
> Laboratorio de Teledetección y S.I.G.
> Centro Nacional Patagónico (CONICET)
> Bvd. Brown 2825, 9120
> Puerto Madryn, Chubut, Argentina
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/grass-user/attachments/20151120/1352c746/attachment.html>