undef
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s1a-iw-grd-vv-20161212t003045-20161212t003110-014339-0173a0-001_filter
s1a-iw-grd-vh-20161212t003045-20161212t003110-014339-0173a0-002_winddir
s1a-iw-grd-vv-20161212t003045-20161212t003110-014339-0173a0-001_winddir