undef

s1a-iw-grd-vv-20170921t224536-20170921t224601-018480-01f204-001_filter

s1a-iw-grd-vh-20170921t224536-20170921t224601-018480-01f204-002_filter

s1a-iw-grd-vh-20170921t224536-20170921t224601-018480-01f204-002_winddir

s1a-iw-grd-vv-20170921t224536-20170921t224601-018480-01f204-001_winddir