undef

s1a-iw-grd-vv-20170312t205934-20170312t205959-015664-019c4f-001_filter

s1a-iw-grd-vh-20170312t205934-20170312t205959-015664-019c4f-002_filter

s1a-iw-grd-vv-20170312t205934-20170312t205959-015664-019c4f-001_winddir

s1a-iw-grd-vh-20170312t205934-20170312t205959-015664-019c4f-002_winddir