GRASSを用いたオブジェクトベース分類
2017/05/16 Seiya Ishibashi (一部修正)
What is segmentation?
Segmentation is process which make segment based on the spectrum and geographical info.
Segmentation in QGIS.(OTB)
Segmentation in GRASS.
g.region rast=2016_1207_backscatter_latlon.1 i.group group=test_group input=2016_1207_backscatter_latlon.1 # below command is segmentation process. # If you set threshold at lower value, then segmentation is more in detail (and takes much time). i.segment group=ortho_group output=test1_seg threshold=0.02 # Since threshold is lower value, running takes over 30 minutes. # Then, you need to adjust the threshold value by checking the created map.
i.segment group=ortho_group output=test1_seg threshold=0.1 # takes around an hour. i.segment group=ortho_group output=test1_seg threshold=0.2 # takes over 30 minutes. i.segment group=ortho_group output=test1_seg threshold=0.3 # takes over 30 minutes.
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