Re: [GRASS-user] multi-date image segmentation in grass

2010-09-28 Thread Markus Neteler
On Tue, Sep 28, 2010 at 1:12 PM, maning sambale
 wrote:
> Hi,
>
> I have several Landsat (4-7) images from 1990-2002  which will be used
> for change analysis of land cover.  FAO's FRA-RSS [1] developed a
> standard methodology for integrating multi-temporal Landsat into a
> consistent sample tiles. The article [2] outlined the general method
> as:
>  - Image subsetting
>  - Radiometric normalization
>  - Contrast enhancement
>  - Multi-date image segmentation
>
> Most of the processing procedures I was able to do in GRASS GIS,
> except for the last step.  The process combined the multi-date imagery
> where an automated image segmentation was implemented to derive
> preliminary polygons to identify changes.  I believe they used
> ecognition for the segmentation.

We can (start to) recommend r.seg from Addons for this (I will ask
the author to accept inclusion in GRASS 7 as i.segmentation). We
could greatly improve the performance of i.smap by preprocessing
data with r.seg.

>  I've used i.smap for preliminary
> segmentation on separate dates but not for a combined multi-date
> imagery.  Anyone tried this with GRASS? Can i.pca do this or another
> tool?

I didn't try but it sounds interesting also for us (just lack of time). If could
provide me with a small spatial excerpt of all the channels as location,
I would try a few ideas and report.

Markus

> Any idea
>
> [1] http://www.fao.org/forestry/fra/remotesensingsurvey/en/
> [2] 
> http://www.informaworld.com/smpp/content~content=a923063789~db=all~jumptype=rss
>
> --
> cheers,
> maning
> --
> "Freedom is still the most radical idea of all" -N.Branden
> wiki: http://esambale.wikispaces.com/
> blog: http://epsg4253.wordpress.com/
> --
> ___
> grass-user mailing list
> grass-user@lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/grass-user
>
___
grass-user mailing list
grass-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/grass-user


[GRASS-user] multi-date image segmentation in grass

2010-09-28 Thread maning sambale
Hi,

I have several Landsat (4-7) images from 1990-2002  which will be used
for change analysis of land cover.  FAO's FRA-RSS [1] developed a
standard methodology for integrating multi-temporal Landsat into a
consistent sample tiles. The article [2] outlined the general method
as:
 - Image subsetting
 - Radiometric normalization
 - Contrast enhancement
 - Multi-date image segmentation

Most of the processing procedures I was able to do in GRASS GIS,
except for the last step.  The process combined the multi-date imagery
where an automated image segmentation was implemented to derive
preliminary polygons to identify changes.  I believe they used
ecognition for the segmentation.  I've used i.smap for preliminary
segmentation on separate dates but not for a combined multi-date
imagery.  Anyone tried this with GRASS? Can i.pca do this or another
tool?

Any idea

[1] http://www.fao.org/forestry/fra/remotesensingsurvey/en/
[2] 
http://www.informaworld.com/smpp/content~content=a923063789~db=all~jumptype=rss

-- 
cheers,
maning
--
"Freedom is still the most radical idea of all" -N.Branden
wiki: http://esambale.wikispaces.com/
blog: http://epsg4253.wordpress.com/
--
___
grass-user mailing list
grass-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/grass-user